For a change, this is not a subject-specific post, but a more general catchup on things mappy and not-so-mappy that we’ve been doing. In brief, the three of us who run this blog are all now wearing different hats from the ones we had a few months ago. The massive change in our lifestyles is that we’ve gotten official grown-up jobs, which is one of the reasons this blog’s been a bit quiet in the recent past. We can but hope that that will change as we get settled into our new jobs.

Sajjad is now with Mapbox in Bangalore, Sumandro is Research Director with the Centre for Internet and Society, in Bangalore and Delhi, and I’m Coordinator for GIS and Spatial Analysis at WWF-India. These are, to be honest, rather predictable roles; we started this blog because, other than the fact that we get on rather well, we thought that our shared interest in all things spatial, informed as it was by our different backgrounds in programming*, social policy research* and conservation, would make for an interesting collaboration.

I’ll let the other two talk about their day-to-day work with maps; for now, I’m going write a bit about the work I do. I’m part of the Species and Landscapes team at WWF-India, which consists of ten landscapes across India. As part of the team in Delhi, I’m helping coordinate the spatial information needs for all the landscapes. I’ve been actively involved with a couple of the teams before (the Western Himalayan and Western Arunachal Landscapes), and am looking forward both to meeting old friends and visiting new regions.

Today, I’m working on analysing some human-wildlife conflict data for villages near Ranthambore Tiger Reserve, cleaning up a subset of the recently released 1-arcsecond SRTM data (which is very nice but has voids that need filling) and collecting data on an infrastructure project in Uttar Pradesh that may affect wildlife corridors in the Terai region.

I’m planning a few posts over the next couple of months; one, which has been pending for a while, is a descriptive piece regarding a balloon-mapping aerial photography project I conducted with the Cambridge University Spaceflight Society. Another’s on the connection between the Indian Forest Department’s administrative boundaries and their hierarchy, and there’s also a long-pending post on Indian administrative boundaries, where strange animals like the tehsil and taluk are to be found. Finally, I have the beginnings of a blogpost about the importance of high-quality vector files of protected areas. And this list is only mine; Riju and Sajjad have their own set of blogposts to write.

Speaking of which, both of them will be at the OpenDataCamp in Bangalore next week; I’m not going to be there (since I have work!) but it’s been a great experience with really interesting people every year so far, so if you’re interested in maps and data, you should go too!

*Riju, Sajjad: I wasn’t sure how else to describe your respective interests in 3 words or less, so please feel free to (choose one: edit/get me to buy you a drink) when we meet next.

I’ve had Nanda Devi and the Sanctuary surrounding her in my thoughts for a very long time, and she seemed like a fitting first attempt to bring spatial data out of the digital world and into reality. For the uninitiated, Nanda Devi is a mountain in the Indian Himalaya, and she’s always referred to as she: the goddess in the clouds. Surrounded by a protective ring of mountains, she towers over them all, and this space between the ring and the central peak is known as the Nanda Devi Sanctuary. Due to this ring, the first entry into the Sanctuary was only made in 1934, by Shipton and Tilman and their three porters, who entered via the gorge of the Rishi Ganga; the mountain herself was first summited in 1936 (see- Nanda Devi: Exploration and Ascent, by Shipton and Tilman).

The geography of the region is fascinating ( and the history as well; there’s a nuclear-powered CIA device somewhere inside the Sanctuary!) and the heights and depths of the various relief features make it a joy to visualise. In this post, I’m going to describe, in brief, the steps I used to get from the data to the final model in wood. While I’m sure most of this can be done using open-source tools, as a result of my current University of Cambridge student status and my @cammakespace membership, I have access to (extremely expensive) ESRI and Vectric software, which I’ve used liberally.Relief map of the Nanda Devi Sanctuary and the Rishi Ganga gorge (dark->light = low->high)

I have a repository of digital elevation data collected by the Space Shuttle Endeavour in 2000 (STS-99; Shuttle Radar Topography Mission). It’s freely available from CGAIR-CSI (http://srtm.csi.cgiar.org/) and is not difficult to use. In QGIS, it was cut and trimmed down to my area of interest around Nanda Devi; I was looking for a rough crop that would include the peak, the ring and the Rishi Ganga gorge. This relief map was exported as a GeoTIFF, and opened up in ArcScene, which is ESRI’s 3D cartography/analysis workhorse. ArcScene allowed me to convert the raster image into a multipoint file; as the tool description states, it “converts raster cell centers into multipoint features whose Z values reflect the raster cell value.” For some reason, this required a lot of tweaking to accurately represent the Z-values, but I finally got the point cloud to look the way I wanted it to in ArcScene.

The point cloud (red dots), overlaid on the relief map in ESRI ArcScene

I then exported the 3D model of the point cloud in the .wrl format (wrl for ‘world’) which is the only 3D format ArcScene knows, and used MeshLab, which is an open source Swiss-knife type tool for 3D formats, to convert the .wrl file into a stereolithographic (.stl) file which the next tool in the workflow, Vectric Cut3D, was very happy with. As a side note, Makerware was also satisfied with the .stl file, so it is 3D-print ready.

The CNC router-ready model in Vectric Cut3D

More tweaking in Cut3D to get the appearance right, and the toolpaths in order, and I was ready to actually begin machining. After an abortive first attempt where the router pulled up my workpiece and ate it, I spent some more time on the clamping for my second attempt. First, I used the router to cut out a pocket in a piece of scrap plywood to act as my job clamp; this pocket matched the dimensions of my workpiece exactly. After a bit of drilling, I had my workpiece securely attached to the job clamp, which was screwed into the spoilboard on the router.

The CNC router doing its thing

For the actual routing itself, I used two tools; a 4mm ballnose mill and a 2mm endmill for the roughing and finishing respectively. It took about 45 minutes for the CNC router to create this piece. I love the machine, and am very grateful to the Cambridge Makespace for the access I have to it.

The final product

In the near future, I’m going to try and use different CNC router tools and types of woods to make the final product look neater; specifically, a 1mm ballnose tool for the finishing toolpath would be very nice! I’m also going to try and make relief models of a few other interesting physical features. While I am happy with this initial representation of Nanda Devi, if you have any suggestions as to improvements for future work, I’d be very happy to hear about them! I’d especially like to know if there are any open-source tools out there that can replicate the steps I needed to use ArcScene and Cut3D for.