Geological Contacts: Angular Unconformity Kaladgi Basin

 Remotely India Series #12

Through the Proterozoic Eon, beginning around 2 billion years ago,  extensional forces acting on continental crust opened up several sedimentary basins across what is now peninsular India. Crustal blocks subsided along faults and these depressions filled in with sediments deposited in fluvial and shallow marine environments. These basins were long lived, some lasting for more than a billion years. 

Sedimentation was not continuous.  Pulses of sediment deposition were punctuated by long periods of non deposition. Tectonic movements deformed early deposited piles of sediment. They were uplifted and an extensive basin wide erosional surface formed.

There was then a renewed phase of basin development. Sediment of these successor basins were deposited on tilted and folded older strata. Commonly, these younger packages of sediments are relatively undeformed. They are preserved as mesas and plateaus made up of flat lying strata. This discordance in attitude between two sets of strata separated by a widespread erosion surface is known as an angular unconformity.

In this post I will highlight an angular unconformity from the Kaladgi Basin from north Karnataka, south India. I have used high resolution imagery from Indian Space Research Organization's Cartosat.  Imagery is available for browsing and download from ISRO's Bhuvan 2D web maps.

The first image shows the area around Ramdurg village. The multi-stage history of the basin is readily apparent. The light colored strata exposed along narrow ridges are folded, while the rust brown hills are made up of undeformed sediments. The light toned strata are quartzites of the Bagalkot Group. The brown sandstone which rest on the Bagalkot quartzites are the Badami Group. Standard annotations show the varying dip and strike of the folded Bagalkot sediments. The white cross in grey circle denotes horizontal Badami strata. 

Kaladgi Basin history has become clearer based on recent geochronologic work by Shilpa Patil Pillai, Kanchan Pande, and Vivek S.Kale. They infer that basin initiation occurred around 1.4 billion years ago. Sedimentation of the Bagalkot Group terminated by 1.2 billion years ago. Movement along major WNW-ESE and tranverse NNE-SSE to NE-SW trending faults deformed the Bagalkot sediments into a series of folds around 1.1 billion years ago. This was followed by uplift and erosion of these folded sediments. Deformation was accompanied by low grade metamorphism of these rocks.

The basin floor subsided again around 900 million years ago initiating deposition of the Badami Group of sediments. The famous cave temples of Badami have been cut out from the lower part of the Badami sedimentary sequence.

The next imagery is a good example on how to recognize the relative timing of deformation events. Arrows point to fracture sets in the Bagalkot quartzites. These lineaments do not extend into the Badami sediments implying that fracturing occurred during an earlier phase of deformation. 

Let's look at a location that shows the angular discordance between the Bagalkot and Badami sediments. This is near Shirur town, north of Badami.  The lighter toned steeply tilted Bagalkot sediments outcrop as E-W trending narrow ribbons, north of Budanagad village. The brown colored Badami sediments form a more extensive plateau. Since these strata are horizontal, the traces of bedding planes form concentric bands mimicking contour lines. 

The final location is just south of Ramdurg village. The unconformity here is a little harder to decipher, but you can make out the tilt of the light colored Bagalkot quartzites, annotated by the standard notation of strike and dip. The quartzites form triangular facets sloping eastwards. Like the previous example, the concentric bands of brown in the adjacent hill indicates that this is the overlying horizontally disposed Badami sandstone.

Many Proterozoic basins of India contain such unconformity bounded sequences. Some more classic examples come from the Chattisgarh, Cuddapah, and Vindhyan basins. These sequences from different basins were not deposited synchronously. Each basin has it own trajectory of sedimentation, deformation, and erosion. 

Detailed field mapping, supplemented by absolute dating of rocks wherever possible, is elucidating the complex poly-phase history of Indian Proterozoic sedimentary basins in the context of global continental breakup and reassembly. For arm chair geologists and enthusiasts, easily available web mapping technology makes it possible to join in the excitement of teasing out these terrain's many secrets hiding in plain sight.

Maps: India Contours

Once in a while I point readers to interesting and useful web mapping applications. Last week, Raj Bhagat Palanichamy, a specialist in GIS and Remote Sensing,  showcased a contour map on his Twitter feed. Intrigued, I found out that the contour map was from a web based application developed by Axis Maps. A detailed blog post explains how they developed the application and the elevation data sources they used to generate the contours. It is quite easy to use, with some controls to set contour intervals, line color, and to depict relief in color shades. 

I am putting a few examples from different Indian terrains to showcase this utility. It is not meant to be a critical review of the app (map scale is missing!), but a fun exploration of its capabilities, and the insights one can get about topography and other aspects of geomorphology and geology. Each example has a contour map on top and a satellite image of roughly the same area in the lower panel. All contours maps have been created using Contours- Axis Maps.

Western Ghats- Edge of the Deccan Plateau: Ghangad, Tail Baila Mesas

The edge of the Deccan Plateau has been deeply dissected to form some stunning relief. Steep sided ridges, mesas, and pinnacles poke upwards from more gently sloping and flattish surfaces. This step like appearance occurs due to the differing styles in which lava flows of varying hardness weather and erode away.  Towards the left-center of the contour map, where the brown meets the darker green, is what appears to be a sinuous thick brown line. It is really an amalgamation of contours, spaced closely, due to the extremely steep slopes and cliffs that make up the Western Ghat escarpment. There is a sudden fall there from the plateau to the coastal plain. Contour interval is 100 feet. 

Himalaya-Tibetan Plateau

Notice how the closely spaced contours in the lower left of the contour map give way to more openly spaced contours towards the top right of the map. This is the transition from the Gharwal Himalaya in to the Tibetan Plateau. The Himalaya, because it receives more rainfall, has more prominent relief, formed by rivers carving deep valleys, and glaciers gouging out rock faces into steep sided, sharp edged mountains. The Tibetan Plateau, although also standing high at around 4500 meters, is in the rain shadow region. It shows less relief. 

This has impacted the geology too. In the Himalaya, the rapid stripping of rock cover over millions of years has exhumed rocks which were once buried 25 kilometers below the surface. In Tibet, lesser erosion has meant that the surface geology is still dominated by 'supracrustal rocks', either volcanic or sedimentary rocks formed at shallow levels of the crust. Erosion has not dug deep down. Contour interval is 500 feet.

Nallamalai Fold Belt- Andhra Pradesh

This map shows the folded ridges of sedimentary rocks formed in the Cuddapah Basin around 1500-1600 million years ago. A fine example of topographic expression giving away the geologic structure of the rocks. Contour interval is 200 feet. 

I would urge those readers who are on Twitter to follow Raj Bhagat Palanichamy's excellent account (@rajbhagatt). He is a mapper par excellence.

Field Photos: Glacial Deposits Of The Darma Valley, Kumaon Himalaya

During my recent trek to the Panchachuli Glacier in the Kumaon Himalaya, I obsessed about observing changes in metamorphic grade of the Greater Himalayan Sequence on the trek route and also about finding the South Tibetan Detachment fault system. I wrote about this in an earlier post.

But there were other interesting geological observations too. The Panchachuli Glacier has left a thick record of glacial deposits. The river Dhauliganga originates from this glacier. Along this river valley, glacial deposits can be observed to a distance of at least 5 kilometers downstream of the present location of the snout of the glacier, indicating that the glacier was much more extensive in the past. Tributary glaciers flowing out of the ranges east of the Dhauliganga have also left an extensive record in the form of thick fluvio-glacial deposits. These can be observed as far south as the village of Baaling.

We heard anecdotes in village Dugtu about how this glacier was much bigger in living memory and how it has been receding rapidly in the past few decades. On one level such stories are believable because studies of Himalayan glaciers have shown that many of them have been shrinking over the past few decades (ref). This is partly due to anthropogenic global warming, but glacial response to warming may be varied due to local variations in topography, precipitation and wind conditions. Some glaciers don't show retreat while some are actually seen to be expanding. Overall though, there a substantial ice loss observed across the Himalaya. Exactly how much of that is due to recent global warming and how much, as some scientists caution, due to natural factors is still being studied. Sustained warming though will cause these glacier to shrink further over the next century.

There is also a longer geological story of glacial advance and retreat written in these deposits.

I've embedded below an annotated interactive map of the glacial deposits of the Dhauliganga river valley in the Panchachuli Glacier area. This will enable readers to zoom in and recognize the various glacial landforms present in the valley. You can also access it via this Permanent Link.



The annotations depict:

a) The dark blue lines are the snout of the glacier.
b) The light blue lines are the recent terminal moriane fields.
c) The pink lines are older lateral moraines.
d) The yellow lines are outlines of older fluvio-glacial deposits
e) Numbers 1 -12 mark the locations of glacial deposits.

I have mapped only a few representative examples of each of the feature types. Readers can use these to explore similar features scattered throughout the valley. 

Location 1: This is the snout of the glacier. It is a mass of ice and frozen mud. The river Dhauliganga emerges out of an ice cave.

Location 2: Taken from near the snout of the glacier looking downstream. Ridges of the terminal moraine can be seen in the foreground. The arrows in the background outline a ridge of an older lateral moraine. Notice how the ridge decreases in elevation downstream suggesting that the terminus of this older glacial phase in somewhere nearby downstream.

Location 3: The older lateral moraine can be clearly seen as a sharp ridge line (arrow) separated from the valley wall by a depression. 

This moraine top is a few hundred meters above the valley floor implying that the glacier was thicker in the past. When was this lateral moraine deposited? It may be at least a few hundred years old. In the Garhwal Himalaya, similar older lateral moraines close to the glacier has been dated to be several hundred years old. They have been interpreted to be a result of glacial growth and deposition during the Little Ice Age, a period of earth cooling and climate instability that lasted from around the 1300's to the mid 1800's (for more on this climatic episode, I recommend Brian Fagan's book The Little Ice Age: How Climate Made History 1300-1850).

Location 4: A view of the glacier and an older lateral moraine (arrow) on the other side of the valley.

Location 5: Further downstream are thick glacial deposits. The river has incised or cut through these sediments. As a result the deposits form flattish plateaus or terraces that hug the mountain slopes. Village Dugtu, where we stayed, has been built on top of one such glacial terrace. The arrow in the top picture points to an exposure of these glacial deposits. A close up of this deposit is seen in the bottom picture. Notice the extremely ill sorted texture. Such ill sorted sediment deposited by glaciers is called Till. Large boulders are mixed in with  gravel, pebbles and much finer sized rock flour (the light to brown colored matrix).

Location 6: Another exposure of a glacial deposit near Dugtu. Again, notice the ill sorted deposit. However, at the top is a well sorted pebbly layer. This suggests deposition in more vigorous flowing water. Glacial retreat from time to time would have resulted in the establishment of a fluvial regime and deposition in these streams. These deposits may be a few hundred to several thousand years old.

Location 7: The glacial terrace on which village Dugtu is built is seen in the lower right corner. Farther away is village Philam built on the thick fluvio-glacial deposits of a tributary glacier originating in the range east of Dugtu. At village Dugtu, the east flowing river Dhauliganga makes a sharp southerly turn. The river has cut through these deposits and the slopes of the valley are thickly forested suggesting the great antiquity of these deposits.

Location 8: A nice view of glacial deposits south of village Baun along a smaller tributary of the  Dhauliganga. Notice the waterfall!

Location 9: A walk right through these thick fluvio-glacial deposits along a forested section of the valley slope. Again, notice the ill sorted nature of the deposits. Glacier are viscous and cannot sort sedimentary particles like water or air can. The result is a jumble of boulder, gravel and rock flour.

Location 10: Another cliff made up of fluvio-glacial deposits. I'm calling the deposits east of Dugtu as fluvio-glacial, since I observed intervals which show layering. This suggest deposition in water, either in streams or in melt water lakes and ponds that form in front of glaciers.

Location 11: A thick sequence of fluvio-glacial deposits along the Dhauliganga river. If you zoom and pan the satellite image you can recognize these terraces  southwards almost up to the village of Baaling.

I did not observe such deposits south of Baaling. However, there are smaller glaciers, such as the Naagling glacier, originating in the ranges on either side of the Dhauliganga. There would be smaller deposits scattered in these tributary valleys.

I have been vague about how old these deposits could be. If we assume that the Panchachuli glacier would have attained its maximum extent in the Pleistocene during the Last Glacial Maximum about 20,000 years ago, then the deposits furthest away from the present location of the glacier would be the oldest. As the glacier recedes one should find younger and younger deposits closer to the active glacier.

A study by Dirk Scherler and colleagues in the Garhwal Himalaya found such a pattern. They studied deposits of the prominent Jaundhar Glacier and the Bandarpunch Glacier in the Tons Valley. I've posted below a map showing the interpreted ages of deposition of glacial sediments.

 Source: Scherler et. al. 2010

Notice how the oldest deposits are further away from the present location of the glaciers (eastern most extremity of the map). These oldest deposits point to the maximum extent of the glacier that was reached in the Pleistocene during the Last Glacial Maximum.  However, the decreasing ages of the deposits upstream aren't the result of a uniform recession of the glacier. Instead, they point to several glacial episodes during which the glacier advanced, then receded, and then advanced again during the Holocene. Their data shows five such episodes of glacial growth dated to approximately 16 ka (ka = thousand years ago), 11-12 ka, 8-9 ka, 5 ka and less than 1 ka.


It turns out that the climate history of the Holocene is not one of uniform warming since the end of the last glacial period. The earth has gone through several minor cooling phases during the Holocene. The well known Younger Dryas Event around 12.9 -11.7 ka is one example.  Some studies suggest cooling episodes around 8.2 ka  and around 4.2 ka . And there is the Little Ice Age during the last millennium.

Another climate dynamic is fluctuating monsoon strength through the Holocene. The authors don't favor the explanation that these periods of glacial growth were triggered by global cooling events.  They argue that glacial growth corresponds to small phases of increased monsoon strength interrupting a longer trend of decreasing monsoon strength. More moisture means more snow and glacial growth. Since the long term trend in this part of the world is one of decreasing monsoon strength, every successive phase of glacial growth was smaller than the previous, resulting in younger and younger deposits upstream. The Little Ice Age deposits (which were likely driven by global cooling and not necessarily increased precipitation) mark the last major phase of glacial growth.

How are these deposits dated? Scherler and colleagues use a technique known as cosmogenic nuclide dating. This technique is one way to date the timing of surface exposure. Glaciers carry rock debris. These form a layer below the moving ice. When the glacier recedes the rock debris is deposited as a moraine or as an erratic boulder. It is exposed to the atmosphere and starts getting bombarded by cosmic rays. Energetic cosmic ray neutrons falling on atoms of minerals like quartz results in spallation reactions. This means that the collision of neutrons is energetic enough to fragment the nucleus. Oxygen bound up with silicon in the mineral quartz gets converted to an isotope of Beryllium (10Be). The amount of nuclides generated this way is proportional to the length of exposure. By measuring the amount of 10Be and comparing it with other isotopes, an 'exposure age' is estimated. This is essentially the age of glacial recession and the deposition of glacial sediment.

Samples have to been selected carefully for this method to give a true estimate of surface exposure and deposition. Care must be taken to avoid sampling rocks that have been repeatedly buried and exposed. Rocks which show signs of being subjected to prolonged glacial erosion are selected since  erosion will remove outer shells of material that may have accumulated nuclides during an earlier period of exposure.  Debris with a polished surface or with striations and grooves generally suggest subglacial transport and prolonged glacial erosion and are preferred samples.

 The figure below taken from the same study shows the reconstructed glacial extents using exposure dates of the moraine sequences in the upper Tons Valley.

Source: Scherler et. al. 2010

Such dating of glacial deposits at other locations in the Garhwal Himalaya (ref) tell a similar story of glacial growth and decay over the Holocene. And what about the Pleistocene? Is there evidence of older glacial cycles in the Himalaya? There are many studies that have identified glacial phases during the Pleistocene as well. For example, in northwest Garhwal, the Bhagirathi Glacial Stage has been dated to 63 ka (ref). And in the Ladakh Himalaya the oldest glacial stage has been dated to 430 ka (ref). Pleistocene ice ages have impacted glacial dynamics in the Himalaya too although more work needs to be done to understand the specific mechanisms of glaciation.

Location 12: Its back to the Dhauliganga valley floor. This moraine ridge (arrows) may be the remnant of an older terminal moraine. It is located about 2 kilometers downstream of the glacier.

The Panchachuli and other glaciers in the Kumaon region to the east of the Garhwal will also have their own history of past glory and recession. How much of the retreat of the Panchachuli and other Kumaon glaciers due to recent global warming?  And what is its fate? Hopefully, someone will study them with more precision in the future.

Exploring India's Paleogeography And Fossils Using The Paleobiology Database Navigator

I was directed to the Paleobiology Navigator by a tweet from @avinashtn .

Great fun! The Paleobiology Database is being maintained by an international non-governmental group of paleontologists. Contributing members add to it fossil occurrences from scientific publications.  The Paleobiology Database Navigator is a web mapping application managed by the University of Wisconsin-Madison that allows you to explore the geographic context of these fossil locations. You can filter the data based on age, taxonomy and geography. You can also generate diversity trends for the selected set.

I played around a bit with India specific fossil locations.

Paleozoic versus Mesozoic Basins

The figure below shows the distribution of fossil localities for the Paleozoic Era. India is shown as it is today and in its Paleozoic geography.

Source: Paleobiology Navigator

You can clearly see that fossils in Peninsular India are predominantly located in one narrow band in the center and east of the country. These are the Permian Gondwana basins. They are, starting from the westernmost and going eastwards, Satpura Basin, Son Valley Basin, Damodar Valley Basin and the Ranjganj Basin.  These are continental interior basins comprising river, lake and swamp environments. Most of India's coal deposits come from these basins. These basins are rich in plant fossils, and reptile and amphibians remains.

Now take a look at India's geographic position (arrow) during the Permian (298-252 million years ago). Peninsular India occupies an interior location within Gondwanaland, far away from any ocean. Tectonic stability through most of the Paleozoic meant lack of crustal movements. During this time, peninsular India was an erosional landscape until the Permian basin formation in the east.

The one Paleozoic fossil location in Rajasthan shown here represents early Permian marine sediments formed by the flooding of the western region by an arm of the Tethys sea.

And this database has still not added one important fossil location. This is the early Cambrian age locality near Jodhpur where sediments of the Nagaur Group are exposed. They contain trilobite trace fossils.  No basin development and sedimentation took place in Peninsular India from Mid-Cambrian to Permian times (530 million years to 298 million years). 

In contrast, look at the northern edge of India, where the Himalaya stand today. That margin was submerged under the Tethyan ocean. A thick pile of marine sediment accumulated right through the Paleozoic, forming the fossil rich Tethyan Sedimenary Sequence of the Himalaya.

Continental configurations changed in the Mesozoic (252 million to 66 million years ago). The figure below shows Mesozoic fossil locations and the Cretaceous paleogeography of India.

Source: Paleobiology Navigator

There is now a wide swath of fossil localities across Peninsular India. The dotted lines trace important linear depressions where sediments were deposited. The east west oriented Narmada rift zone (NRZ; Jurassic and Cretaceous) and the NW-SE oriented Pranhita Godavari zone (PGR; Triassic to Cretaceous) are important fossil repositories.  The eastern India basins continued accumulating sediment. To the west are the basins which formed in Gujarat and Rajasthan (Jurassic and Cretaceous). The Kutch rift (KR) is outline by dotted lines. And to the south east in Tamil Nadu, marine flooding of the eastern continental margin in the Cretaceous resulted in the deposition of richly fossiliferous sedimentary sequences.

All these basins ultimately owe their origin to the forces exerted on the crust as India pulled away (arrow) from Gondwanaland.  Seaways formed along these rifts and crustal depressions. The Mesozoic, especially the Jurassic and Cretaceous, was a time of global high sea levels. The western margin saw marine incursions from the nascent Indian Ocean, while the eastern margin was submerged by the waters of the newly formed Bay of Bengal.  River and lake systems also developed in more continental interior locations. The northern margin (Himalaya) was mostly a marine environment through the Mesozoic.

Marine versus Continental Interior Basins in Mesozoic Central India

The distribution of terrestrial organisms versus marine organisms can tell us about the extent of marine flooding into Peninsular Central India in the Mesozoic.

I created these maps by using localities of dinosaur fossils (above) to map the distribution of terrestrial sedimentary environments. I used localities of invertebrate marine organisms, namely,  brachiopods, echinoderms and ammonoids  to delimit the extent of marine environments along the Central Indian basins (below).

 Source: Paleobiology Navigator

You can see that terrestrial environments were present right across the Narmada rift zone, the Pranhita Godavari rift basin and in the western Indian basins also. In the western basins, some of the dinosaur fossils have been found in marginal marine settings comprising coastal and estuarine environments.

Deeper water marine environments as evidenced by brachiopod, echinoderm and ammonoid localities are however restricted to Gujarat, Rajasthan and western Madhya Pradesh. The Cretaceous Bagh Beds in Madhya Pradesh is the eastern most limit of Mesozoic marine flooding into Central India. Seaways did not extend into eastern parts of the Narmada rift basins.

Global and Indian Dinosaur Diversity Patterns

I used the Stats tool to create graphs of dinosaur diversity. The number of Genus per Stage is being used as a measure of diversity. Geologic time is subdivided in to bins. An Age is a bin spanning a few million years. Stage represents rock layers deposited in an Age. So, a diversity measure has been created by counting the number of dinosaur genus reported from successive bundles of rock layers, each representing a few million years of time.

Source: Paleobiology Navigator

The global diversity pattern shows episodes of diversification and decline in the Triassic, Jurassic and the Cretaceous. There appears to be a trend of increasing diversity through time with peak diversity in the Mid-Late Cretaceous. The Late Cretaceous extinction of dinosaurs forms the right side boundary.

The diversity measures in India show some differences with global trends. The number of Genus sampled are less. This is due to regional versus global sample. A smaller locale will generally have less of the total observed variation. The trends in diversity with time also is different from the global trajectories. There are a couple of reasons for this. First, this is a preservation artifact. Mesozoic terrestrial basins in India were receiving sediment only episodically. Depositional phases were interrupted by erosional hiatuses. Rock sections thus have been removed as well.   There was little to no sedimentation from Mid-Jurassic to Mid-Cretaceous in the Narmada rift basins. Hence, no fossils either. The lost diversity from this interval is irretrievable.

The second reason gives more hope. A couple of years ago, Dr. Dhananjay Mohabey of the Geological Survey of India gave a talk in Pune on Late Cretaceous dinosaurs of India. He mentioned that there are roomful of dinosaur fossils in government archives that are yet to be studied and catalogued. There is scope then to enhance our understanding of at least late Cretaceous dinosaur diversity of India.

I have barely scratched the surface. There are many more stories and patterns and trends in the Indian fossil record waiting to be teased out from this database. Dive in!

Free Download- Cartosat 1 India 1 Arc Sec Digital Elevation Model

I've been writing periodic updates on Bhuvan and have been critical about some of its features before. Today I sing its praise.

Bhuvan is the Indian Space Research Organization's web mapping portal. It was  launched with much hype in 2009, touted by the media as a Google Earth killer.  That it hasn't turned out to be. Google Earth /Maps is still the most used application for browsing imagery and exploring the world's surface.

This need not have been portrayed by the media as a Google versus Bhuvan competition. I always felt Bhuvan would offer real value by making available India specific natural resources and earth science datasets to overlay imagery. That in fact is the direction Bhuvan has been evolving for the past few years.

Bhuvan now offers a variety of  India datasets for overlay, analysis and download. I have been playing around with the Digital Elevation Model (DEM) derived from Cartosat 1 stereo imagery. The DEM is available as 1 degree tile corresponding to the Survey of India topo map sheets. The interface  to  select and download the DEM is easy to use. Technical documentation of the DEM is also available. Spatial resolution is 1 Arc Sec, which corresponds to around 30 meters. The vertical margin of  error is about 8 meters. Analysis shows that the Cartosat DEM compares well with other widely used DEM such as SRTM (90 m res) and ASTER (30 m res).

Below is  a Digital Elevation Model of the Nallamalai Hills in Andhra Pradesh with a 0.5 deg graticule overlain. I've generated this representation in Manifold GIS. The geological terrain is part of the Proterozoic Cuddapah Basin. Remember, the color scheme assigned to the DEM is not demarcating different rock types but elevation ranges. However, as a nod to the prominent geological feature that I wanted to highlight, I have assigned a color of the common rock in outcrop. These are the Bairenkonda Quartzites and Sandstones of the Nallamalai Group which form folded ridges, part of the Nallamalai fold belt. The green low relief areas are mostly underlain by shales and limestones.

And check out the drainage in color black (lowest elevation). You can make out the drainage divide between the Godavari and Krishna basins. In the upper right part of the image, streams are draining north towards the Godavari river. In the left lower part of the DEM, streams are flowing south towards the Krishna river.

Source: Cartosat 1 DEM, National Remote Sensing Centre, ISRO

I'm planning to tell more stories about Indian geology using these DEM 's. For that I  have to thank ISRO for making this dataset available.

Paranoia Over Google Mapping Tools Persists In Indian Officialdom

sigh... I keep writing about this only partly as comedy.. but mostly in frustration...

From an article in the Hindu about the recently held "mapathon"contest organized by Google.

As Delhi Police investigates whether Google violated rules in holding a competition that asked users to add information about their local areas for its online map, the U.S. Internet giant on Saturday said it had responded to queries raised by Survey of India more than 10 days back and hasn’t heard from it yet. (emphasis mine)

Apparently, the Survey of India and the Defence establishment is worried that such initiatives will have grave security repercussions.  The problem is that Google has been asking users to add information about their local areas for its online map for several years now. I just don't comprehend how a mapping contest wherein lots of enthusiasts add places of interest on a map within a short span of time becomes a greater security threat than an individual using Google Maps on any other day of the year.

more from this article in the Economic Times... But on behalf of the Surveyor General of India Swarna Subba Rao, his deputy major general R C Padhi told the three ministries that Mapathon was "not in accordance with the national Mapping Policy 2005 and map restriction policies issued by the defence ministry from time to time", sources said.

Added a senior defence officer, "Such activities can have serious security repercussions in case mapping of restricted areas is undertaken by members of the general public."

The words "general public" come out of the mouths of our officials with such contempt and suspicion. These archaic mapping policies which restrict the "general public" from mapping certain areas have long been rendered meaningless by the many roving eyes that hover above the earth. I am sure the government understands this.. but relinquishing control over anything has always been hard for Indian officialdom.

The exceedingly vast majority of people using Google applications to map India don't want to harm India.

Those who do... might I remind the Indian Government that the terrorists who attacked Mumbai on November 26 2008 did not wait for a mapping contest to survey the city.

ISRO Plans New High Resolution Remote Sensing Satellite

...but will the public have easy access to the data?

Something this article does not address. India's remote sensing program is no doubt a great science and technology success and the imagery and digital data is being used by scientists for research and natural resource management.

Where India and ISRO are falling short is the continued denial of the best quality images to the public at large.  Bhuvan - ISRO's  answer to Google Maps - launched a few years ago is still serving images of India which are frustratingly inadequate for users who have by now become accustomed to razor sharp quality images of their cities and countryside from Google Maps and Google Earth.

The remote sensing satellite Cartosat-2 series has been imaging India using a panchromatic sensor at a 0.8 meter resolution since 2007.  In July 2011 India announced a new Remote Sensing data policy which allowed distribution of 1 meter resolution imagery without additional security checks. The previous policy did not allow unrestricted access to imagery finer than 5.8 meters. The policy change should ideally have resulted in image streaming applications like Bhuvan to present much sharper images of India. Almost two years since we are still getting a grainy view of India from Bhuvan.  Is the new policy not extendable to open access image streaming applications? If so, why not? Pointing to reasons of national security does not make sense since fine resolution imagery is already available through applications like Google Maps to users in India.

The image below of a portion of Pune city is the best resolution available via Bhuvan and it means that tens of millions of potential users will stay away and use Google instead.

U.S. Shale Basins Map On GeoCommons

GeoCommons, the public mapping site run by FortiusOne Inc. has added a map of shale basins of the United States to its database. Go here for the metadata and to create your own map. You can also download this data either as a kml file or a shape file or as a text file.

Since I last visited the site, Geocommons has brought more analytical capabilities into the public domain. Users can now select from a list of spatial analytical tasks like data merging, data aggregation, buffer, intersection, clip. A lot of the familiar GIS spatial functions are now available from the cloud.

You can search for geology and other data sets and can also subscribe to the feed to keep track of new additions. This is really a great open access mapping tool with a very attractive interface and plenty of options to thematically display your map attributes. You can also contribute data. Uploads can be in kml, shape or text format. You can also import data available through a web URL i.e. you can import say a kml file from another server or data that can be shared through a WMS (Web Map Service) which is a protocol for streaming map images over the internet. This way you are linking to data that is stored somewhere else. Your display will automatically update when the primary data changes.

Its really worth your time browsing through this site exploring their data collection and experimenting with making maps.

Bhuvan Continues To Be A Mixed Bag As A Citizen Mapping Tool

After my last post on the use of Google Earth to identify illegal mining in Goa, I was curious to find out if I could replicate the same in Bhuvan, India's public mapping portal.

I was disappointed:

1)  There is no historical imagery available, or at least none that I could find.  So I could not pull out older imagery to verify claims made about the presence /absence of mining before a certain date.  This is not due to a lack of older imagery. The Indian Space Research Organization has had a remote sensing satellite program since the late 1980's and imagery  of at least 23 m resolution is available for  the last couple of decades and imagery of 5.8 meter resolution is available for the last 12 years or so (IRS - 1D). The 5.8 m resolution images are fine grained enough to identify large features like open pit mines.

2) I could not find the open pit mines using "search by name". In Google Earth I could zoom onto the area of the open pit mines by searching for the nearest settlement "Maina" which was mentioned in the article on the Goa mining scam by the newspaper Herald.   In Bhuvan, the search by name database works best for towns and cities. The village level data is still incomplete. Even when a small village is present in the database the imagery does not always zoom to that area, nor is the village annotated to allow easy navigation to it. These are the basics of interactive map navigation design and Bhuvan is falling short.

On a general note, its been close to three months since the government announced that 1 meter resolution data will now be available without need for security clearances. Yet Bhuvan still is not streaming imagery finer than 5.8 meter resolution.

On the data download front, elevation data of CartoDEM 1 arc second (Digital Elevation Model derived from Cartosat 1 imagery- 1 arc second corresponds to roughly 30 meters) and Resourcesat-1: AWiFS imagery (56m) of the Indian region can be downloaded from the NRSC Open EO Data Archive. You can choose the product and the area of interest from the Bhuvan interface. The DEM download is a welcome addition. You could previously download 1 km resolution DEM of India from the USGS and also 30 m relative DEM generated from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) from NASA.

However, regarding imagery the government's all too cautious approach is perplexing. If 5.8 meter resolution and 1 meter resolution data are available and now cleared for access to all users without further security checks, why not let users download that data too?

Catching Illegal Mining In Goa Using Google Earth

Ogle Earth points to the use of open access tools like Google Earth to alert us to the possibility of illegal mining. From their blog:

There is a juicy scandal unfolding in India’s smallest and richest state, Goa, where the State Assembly’s Public Accounts Committee (PAC) has prepared a report indicting ruling Congress Party politicians for benefiting from illegal mining in the state. Illegal mining is estimated (by the Hindustan Times) to have cost Goa over USD 600 million over the past five years in lost tax revenues, turning this into a whopper of a story.....

...India’s national Directorate of Mines and Geology has now also taken an interest in the mine, ordering it to immediately cease production until it is investigated. An article by Goa’s Herald spells it out for us:

Tarcar has cheated the government by avoiding huge amounts of export duty by under-invoicing of his exports.

When presented with evidence of massive ore dumps that could not have been produced within quota, his mining company contended that these were from earlier activities. Google Earth’s imagery from 2003 effectively catches the company in a lie.

Check out the imagery here. No open pit mines in 2003. The 2011 imagery shows large open pit mines.

These ores are part of the rich iron ore belt of Goa. They are Precambrian Banded Iron Formations generally thought to be of sedimentary origin and are associated with medium and high grade meta-sedimentary rocks of the Archean schist terrain that makes up large portions of south India.

Online Interactive Geological Map Of India

I keep tabs on the India Biodiversity Portal, one of the best India based open access web mapping applications focusing on natural resources.

They have online now an interactive geological layer created by digitizing likely 1 : 1 million scale Geological Survey Of India geology maps. The contributor is R. Ravindranath of the Foundation of Ecological Security. You can click on geological units and get a description of the unit. You can also thematically style the geology based on Geological Age and Lithology. And you can control transparency so as to get an idea of the relationship between say physiography and geology. The physiography layer is one of the Google base layers available for display.

Other geology related overlay layers are India Aquifers, India Soils, India Geomorphology and India River Basins. I wish they had different display styles like transparent cross hatch, dots, symbols and lines and so on to choose from to enable easy visualization of multiple themes but perhaps that is something for the future. Unfortunately none of these geology layers are available as downloads. Government owned vector data is still not being distributed freely in digital format. I hope there is a change in policy on that soon.

But this is an important and growing resource for geology and biodiversity data. You can register and contribute layers to the natural resources database. Most Layers not under government control are downloadable (as shape files, GML and text) but contributors are free to choose the level of restrictions they want under a Creative Commons license.

Mapping India: Another National GIS Effort Launched

From a trickle to a flood; the number of government backed initiatives to develop map based applications intended to reach and involve citizens to help manage India's natural and urban resources have increased over the last decade.

The latest as reported by the Economic Times is the National GIS, what appears to be a massive effort to standardize available spatial data and build resource management applications, served out over the web to different users.

I don't have enough details to comment on the particulars, but some thoughts -

The effort is touted as something of a brand new venture, although I suspect that existing applications and ongoing efforts will be grafted onto this new entity. For example, Bhoosampada (new link) allows users to browse and search for landuse and landcover data. And the National Urban GIS Mapping Mission which has promised to build standardized urban data sets is supposed to be underway to map urban areas and develop applications to aid urban governance.

My hope is that the new National GIS is not a massive duplication of efforts and that these older intiatives with some improvements will be brought within a wider umbrella effort.

There is going to a citizen layer in this application which will allow citizens to geo-tag their complaints. The principle is admirable but better governance is more hostage to a mindset than it is to technology. Today, I can either email or call or put up a status on the Pune Municipal Corporation or Pune Traffic Facebook page about a particular grievience, but the response rate is abysmal. Unless a method of personal accountability is tied up with the complaint workflow, I don't see how the citizen layer will lead to a better government -citizen partnership.

Still, it is something of a wonder that more and more government data locked up previously is making its way into the public domain. ...slowly..but that counts for progress nevertheless.

Does The Indian Govt Prefer Google Over Bhuvan?

From a note in Geospatial World I learn that the Election Commission (EC) of India might be using Google satellite images as a background layer on which to placemark the locations of polling booths along with relevant information. The project will be initiated in the state of Bengal.

If this report of using Google is true, I am curious to know why the EC chose Google over Bhuvan which also serves out satellite images and is advertised by the Indian Space Research Organization (ISRO) to be customizable to incorporate the kind of functionality the EC wants.

Is it because - a) the EC was not aware of Bhuvan and its capabilities? In that case, ISRO has not done a good job of educating potential users about Bhuvan.

Or is it because - b) the Application Programming Interface i.e. the programming tools that allow developers to customize the application is not good enough?

Or is it because - c) Data policy restricts even government departments from accessing very high resolution imagery (1 meter) from Indian satellites for web applications, even internal ones like the proposed polling booth app. Government users may obtain without clearances high res images of a pre-defined extent i.e. images of one particular geographic area, but is a high res seamless image stream available to them through  Bhuvan?

Currently the data policy allows only imagery of resolution 5.8 meters and coarser to be released free of clearances in the public domain. Due to this policy Bhuvan can only stream images of 5.8 meters and coarser to the general public. The policy is supposed to be up for a review this year.

Whatever the reasons, it's a shame that Bhuvan and high resolution imagery captured by Indian satellites is being kept away from being utilized in innovative applications.

The government and ISRO need to introspect.

United States Water Usage Maps Through Geocommons

Just a pointer that GeoCommons, a public domain web mapping application by Fortiusone Inc has a growing collection of geology and natural resources data.

I've been having fun last couple of days downloading some U.S. water use datasets, importing them in Manifold GIS, making them map ready and then uploading them back on Geocommons. Using the Map Maker I have then presented the results in a couple of maps.

The first shows the total ground water usage by state in millions of gallons per day (colored states) and also ground water use as percent of total water use (graduated dots). Orange blocks as urban centres with population greater than fifty thousand. You can see the east west divide in water use type. The east relies a lot more on surface water. The central and western areas along with Florida in the south east rely on ground water more than the eastern states. The importance of the Ogallala or High Plains Aquifer is clearly seen in the central states as is the importance of the Central Valley Aquifer in California.

View full map

You can drill down and bring out other dimensions of this data. For example in the map below I've plotted one of these dimensions, the ground water usage for irrigation in millions of gallons per day in the High Plains counties. The High Plains Aquifer is outlined.

View full map

This is not a full "cloud GIS" yet in terms of users borrowing or leasing the full range of GIS functionality from a remote computer. I had to follow a hybrid approach as did other data donors in terms of using a personal GIS to process the data to certain specifications before uploading it to this online service. Still such services are gaining importance and functionality and they give users who don't own software an inexpensive tool to actively engage with spatial data.

A New Version Of Bhuvan Has Been Released

The Indian Space Research Organization has released a new beta version of Bhuvan a web mapping tool which serves images of India and the rest of the world taken from various Indian remote sensing satellites. It is available in 2D and 3D versions.

The new versions looks a little slicker and cleaner than its predecessor. But 5.8 meters is the highest resolution imagery available via Bhuvan while Google Maps and Google Earth both have long started serving 1 meter or so images of Indian cities and hinterland.

In case you are wondering why, here is the Remote Sensing data policy of the Government of India:

Government prescribes the following guidelines to be adopted for dissemination of satellite remote sensing data in India:

All data of resolutions up to 5.8 m shall be distributed on a nondiscriminatory basis and on “as requested basis”.

With a view to protect national security interests, all data of 5.8 m and better than 5.8 m resolution images will be screened by the appropriate agency before distribution so that images of sensitive areas are excluded.
           
a. Data of 5.8m and up to 1m resolution can be distributed to users after screening and ensuring that the sensitive areas are excluded.

b. Data of 1m resolution and better will also be screened as above and the following procedure will be followed for its distribution.
                 
i. Government users can obtain the data without any further clearance.
                
ii. Private sector agencies, recommended by at least one Government agency for use of 1 m and better resolution data for supporting development activities, can obtain it without any further clearance.
                
iii. Private, foreign and other users can obtain the data after further clearance from an inter-agency High Resolution Image Clearance Committee (HRC).
                 
iv. Specific requests for data of sensitive areas, by any user, can be distributed only after obtaining clearance from HRC.
                
v. Specific sale/non-disclosure agreements to be concluded between NRSC and users for data of 1 m resolution and better.

What this means is that under the current policy scenario, high resolution (1 meter or so) images collected from Indian satellites will not be available via open access free web mapping tools like Bhuvan. The only users of this high res imagery will be those who have obtained clearances for images of pre-defined geographic extent to be viewed in specialized GIS and Remote Sensing software.

This will severely limit the user base of Bhuvan and Indian imagery:

For example-

1) That means despite a developer API for Bhuvan being available there will likely be few takers especially for designers of urban applications.

2) And Bhuvan for the mobile market?... all those location apps, business listings, navigation already available via Google..?... forget it.. can't be done when your street and neighborhood looks like an undifferentiated granular blob.

3) Additional India specific thematic layers..?... many already  available at other free web mapping apps like Geocommons, India Biodiversity Portal,  Bhoosampada, and  Census India Web Mapping.

unless there is a policy shift with regards to availability of high resolution images... I don't see the point of Bhuvan..

The Passionate Saga Of India's Spatial Data Infrastructure

Why passionate?.... feel free to scroll to the bottom of the post for that tidbit..

I've been having an email conversation with a reader about India's National Spatial Data Infrastructure (NSDI), the promised digital gateway to spatial data on the country's natural resources, urban infrastructure, demographic information and so on.

To summarize the technological components that need to be built for the NSDI to become functional -

1) Contributing agencies have to get their data digitized and metadata available to NSDI standards.

2) Contributing agencies have to develop web map applications to view and query this data.

3) The NSDI portal will be a centralized gateway to this data and applications and also provide additional mapping applications at various levels of user access.

Right now all this is still something of a mirage. The web portal is up but not quite functional, since all contributing agencies have yet to make available data and applications to access and query this data. Still the NSDI portal is an interesting place to visit if only to get a glimpse of its immense potential. A list of and links to the contributing agencies are available.

To those frustrated users of spatial data, conditioned by the stifling bureaucracy to filling out forms and waiting for months to get security clearances to use data, the prospect of a one click access to spatial data is a wish too good to be true and cannot come soon enough.

Some of this one click nirvana is already a reality with individual government and non-government initiatives publishing their data via web maps. I made a quick list of available services:

1) Bhoosampada- Indian government initiative to share land use land cover data

2) Bhuvan- Touted as a Google Earth killer, shares satellite images and some natural resources layers

3) Census India Maps: Indian government initiative to share census data.

4) The Indian Bioresources Information Network: Indian government initiative to share biodiversity and forest data. I have not been able to register as a user at the time of writing.

5) Central Ground Water Board Map Service: Government released data on groundwater. I have not been able to register to this at the time of writing.

6) Wasteland Information System: Government data on wastelands. This as yet appears to be an internal application, not released in to the public domain.

7) India Biodiversity Portal- Non-Government initiative to distribute natural resources and census data.

Besides these, no doubt there are plenty of internal applications being used by various government agencies. Eventually all these services will be absorbed under the NSDI umbrella along with the already named contributors and other new interested parties who want to part of this national data service.

I have been showering praise on government efforts so far. Now its time to turn around and give a sharp kick in the buttocks.

I have tried to register to a couple of these applications and have got no response from the contact personnel assigned to deal with this. A more friendly and responsive interface with potential and existing users must develop. Also all these above government applications need to be rethought from a design perspective. Users are becoming more aware of location based services and the slick interfaces through which such services are being rendered on their PC's and mobiles. The clunky interfaces of these government applications might turn away lots of users... and thirdly... usability...usability..usability... that should be the mantra. As of now the data structure, the menus and the query design...all assume specialist users. For the curious citizen not trained in navigating map services and not used to looking at underlying data,  it will be a tough slog to extract any useful information. The interfaces need to be simplified...

Finally, coming to the passionate part of this saga, I noticed a link on the lower right side of the NSDI portal titled "NSDI A Passionate Saga". Curious, I downloaded the document and found out it was a personal account of the building of the NSDI from concept to its as yet be fully realized status written by the people involved.

It was a bit like the documentaries you see on HBO these days about Hollywood movies.. "The Making Of...such and such"...

but keeping with Indian government policy...without the coy references to the sex scenes.

OneGeology Portal For Viewing Country Geology Maps

Here is a useful tool to explore over the weekend. A reader pointed me to the OneGeology Portal, a web map application that serves out 1 million plus scale (mostly) geology maps, country wise.

The portal is an initiative by various geological survey's to share digital geological data via a common web platform. The data is housed in contributing countries data servers and shared via a distributed web service.

Here is what the interface looks like.

It is very easy to navigate. You can't directly download actual spatial data..for that you have to contact the data owners. But you can save a KML file and then import that in some other web service like Google Earth. Or you can save a Web Map Context - which saves pointers to the layers you have displayed as an XML file - and import that as an overlay the next time you go online. That way the configuration of layers you have opened in one session can be saved. You can also copy and share the URL of the data server to use in some other mapping application like Google Earth or NASA World Wind. That allows you to mix your geological map with other non-geological data you may have stored elsewhere.

..sigh...... India has not contributed.. Afghanistan and Yemen have their data up but India doesn't. The Geological Survey Of India (GSI) has digitized geological data but is not.. how shall I put it... "into" data sharing as proactively as it should. For those interested, India geology data is available for viewing through the India Biodiversity Web Mapping application which I rank as the best public domain natural resources web mapping app in India. Someone has gone through the trouble to collate, digitize and upload that data, curiously with the permission of the GSI..one hopes the GSI takes a cue and develops its own data sharing infrastructure soon.

The OneGeology program is being administered by the British Geological Survey while the web mapping service is being hosted by the French Geological Survey.

Updated California Fault Map Released

The California Geological Survey on its 150th anniversary has released an updated version of a fault map along with an updated version of a rock and soil map.

The maps are available as interactive Google Maps.... dare I say ...mashups?

The idea is that knowledge of the location and types of faults will guide decisions on where to build and on construction standards.

You can view the fault map here and the geological map here.

Tip: NYTimes

Mapping India: Can The RTI Be Extended To The NSDI

A clarion call seems to have been issued by the high priests of Indian government spatial data--

Resistance is futile...join the collective.

The Borg in this case is the National Spatial Data Infrastructure (NSDI), an ambitious, much needed, slowly being built but yet to be fully realized vision to enable easy open and quick access to public domain spatial data.

The latest  to join this collective is another web mapping application, this time developed by the Central Ground Water Board. I began this post wanting to review it, but found it agonizingly slow the few times I tried to use it.

Instead I started thinking about the NSDI and what it could potentially do to facilitate a better engagement of civil society with government...more specifically..

can the mechanism of acquiring information through the Right To Information Act (RTI) be extended and modified to these web mapping applications under the umbrella of the NSDI?

Traditionally users of spatial information in India fall into two extreme categories. There are those "lightweight" users who go on the excellent mapping services of Google, Yahoo..so on and use the images to locate items of interest, find directions, distances and create custom maps by putting placemarks and routes. The image quality is excellent but the apps have no serious analytical capability.

At the other pole are "serious" GIS users who access spatial data from heavyweight GIS and image processing packages with extended analytical and mapping capabilities. These users are spatial data professionals working in both the public and private sector.

The NSDI will create a third kind of a user....someone who may not formally work in GIS, may not have access to or afford access to a GIS, but nevertheless may want access to spatial data and may want to ask sophisticated spatial questions. The web mapping applications that owners of public domain spatial data must create, will provide a gateway to such user aspirations.

This opens up exciting possibilities for civic groups, NGO's and curious citizens..the third user group.. so to speak, who want to examine and question government on the status of natural resources, urban planning and developmental projects..all areas where spatial reasoning is critical.

Entering a web mapping app via the NSDI it would be possible for example to ask:

1) For a particular area..show me the locations of ground water wells with contaminants above a specified quantity, within a specified distance of a known point pollution source...potentially through the CGWB web app

2)  For Ward X of city Y...prepare a map of lakes and streams and encroachments within these green zones...potentially through the Urban Mapping Mission websites.

3) ...For district X prepare a map of forest land with various levels of legal protection and the location of planned developmental projects within and near these forests...potentially through the Ministry of Environment and Forest website.

There will be some limitations to this kind of approach to information access:

1) The type of information a user may want is not included as a spatial layer in that particular web app.

2) The web app is not equipped with a query engine capable of performing the analysis.

3) The user knows what (s)he wants but does not have the expertise to perform the analysis.

4) The query might encompass a very large area and might run into bandwidth and application performance issues.

..so..  why not bypass these limitations which are sure to crop up and enable the user via the mapping application to compose a question, not using the formal query engine but ...in plain language like the ones above... and send them to a designated Spatial Information Officer. That officer - and each public domain web mapping application will have one -  will process the query using a GIS and if required gather information from other sources and send the compiled answer within a specified time line.

The answers would be sent as a map in an image format and associated attribute data could be sent as an excel or a database file. Administrative costs can be charged through online credit card payments or can be sent via a check.

In effect the RTI will be extended to include these public domain web mapping sites as an official application counter for information. 

At present the NSDI and each of the associated agencies do have an RTI officer. But you have to apply to a central office for information. That central office may not have developed the needed synergy and cooperation with its GIS office to efficiently process your query.

I am thinking in terms of a decentralized mechanism wherein queries are sent directly through individual web mapping applications to the spatial information officer in charge of that application and answers to these queries are generated by processing the spatial databases underlying the web mapping app.

I have a feeling that something along these line must be put in place if the NSDI wants to fulfill its promise of open access to data. The first few web mapping sites I have come across do not have truly dynamic query engines that would enable a user to perform sophisticated analysis. Besides, the government may choose to present the pubic with only a limited view of the total data set.

Placing these web mapping sites within the ambit of the RTI would mean that all the information sitting in the underlying databases and not just the subset view presented via the mapping applications will be open to and can be accessed by the public.

Moreover, the spatial layers and associated databases if correctly attributed and structured,  will give results to queries potentially within a few minutes.  So this method will have a huge advantage over a traditional RTI query, the answer to which will have to put together painstakingly from disparate files  which may not yield very well to spatial queries.

Mapping applications under the NSDI will allow citizens to view, browse and query public domain data with a geographic context. Sorting through data this way..thinking of spatial relationships between objects... may inspire citizens to think of new questions to ask and in to new ways of analyzing information. A more productive and open relationship between citizen and government can be forged if the NSDI opens up to these possibilities.

See: Mapping India