Friday, 14 May 2010

Arunachal Pradesh: 3km and above

I've been working on some maps of Arunachal Pradesh; working with ArcGIS is NOT fun. However, ArcGIS together with some file-handling tools (Belvedere), basic Python scripting and ERDAS Imagine makes life a little easier. Not much, but a little:)

This particular set of maps was generated to identify high-elevation regions that may benefit from protected status. In this case, all regions above 3000m in altitude, in Arunachal Pradesh, were identified based on SRTM data. This information was then used to mask a composite Landsat image, which is my intended product.

This is a simple SRTM altitude map of the state.

This is a false-colour Landsat composite of bands 7,5 and 4. The Landsat scenes that comprise this image have been taken in the winter months of 1999, 2000 and 2001.

I've segregated the altitudes into two bands to create a mask; the red indicates areas that are above my target elevation of 3000m, while black indicates areas with an elevation below 3000m.

Finally, I've overlaid the altitude mask on my Landsat imagery and adjusted its transparency and colour so that areas above 3000m now show up very clearly. On the basis of pixel ratios, I estimate that these high-altitude regions make up slightly under 25% of Arunachal Pradesh's total land area.

1 comment:

  1. These maps look interesting. What resolution was the SRTM used at?