Kaveri River - drainage areas in Karnataka and Tamil Nadu

This video shows how I computed sub-basin areas for the Kaveri river in the Indian states of Karnataka (KA) and Tamil Nadu (TN). Data for drainage areas came from AQUASTAT and was processed in QGIS open source software. I then created this video using Flashback Express 5 screen recording software.



Process:

• Intersect layers for administrative boundaries and sub-basin areas to obtain sub-basin areas by state
• Extract sub-basin areas by state layers into two separate layers (KA and TN) 
• Dissolve the two layers to get total area by state

The values I computed for drainage areas: 35462 sq km (KA) and 44422 sq km (TN) India Water Resource Information System (India-WRIS) provides these values for drainage areas: 36240 sq km (KA) and 48730 km2 (TN)

Kaveri River dispute

The recent MLA election in Karnataka obscured pressing issues such as water. I stepped in to create maps of rivers.

Rivers of India

I champion open principles: open data, open software, and open standards.

Natural Earth is a public domain map dataset that provided data layers for shaded relief, internal administrative boundaries (states),water bodies, waterways, and populated places. The datasets are available at 1:10m, 1:50m, and 1:110 million scales. I chose datasets at 1:10 million, the most detailed that Natural Earth provides.

I processed the layers in QGIS, which is built on top of and is Free and Open Source Software (FOSS). QGIS uses the GNU General Public License (GNU GPL).The Free Software Foundation sponsors the GNU Operating System. FOSS software licenses grant the users rights to modify and re-use software product.

At the India extent, I applied labels for the states. Going on the premise that named waterways are more significant than unnamed waterways, I created separate layers for named and unnamed waterways. The named waterways were portrayed with a thicker line, while the unnamed waterways were portrayed in a lighter blue color and a thinner line. 

I also created separate layers for rivers with a specified width and rivers with an unspecified width.  Those rivers that had a specified width were deemed more important than those that didn't: likewise, they had a thicker line.

Kaveri River

I then selected administrative boundaries for Goa,Karnataka, and Tamil Nadu; saved them to a new layer; and zoomed in on the layer.In addition to labeling the states, I labeled populated places. Natural Earth favors regional significance over population census in selecting populated places. I also selected segments for the Kaveri River (waterways named Kaveri), saved them to a new layer, and styled the layer with a thick blue line.

Sources:

Front Page - Free Software Foundation - working together for free software. (n.d.). Retrieved May 16, 2018, from https://www.fsf.org/

GNU Operating System. (n.d.). Retrieved May 16, 2018, from http://www.gnu.org/

Natural Earth. (n.d.). Retrieved May 16, 2018, from http://www.naturalearthdata.com/

QGIS. (n.d.). Retrieved May 16, 2018, from https://www.qgis.org/en/site/