Thursday, February 19, 2015

Thursday Thoughts: VMAP0 shapefiles for Chile?

Presently, I'm working on creating some GIS-based analyses of Chilean rivers and river ecology. However, Chile being Chile, a lot of the data (both GIS data layers and river ecology data) are not readily available. Therefore, in order to get GIS data, I have to find whatever publicly available GIS data are online and use those.

I spent the last week developing a hydrology layer from a relatively high quality DEM, and - happily - the results of deriving hydrology from a DEM were generally confirmed by lower-quality GIS layers of water courses. (I used these lower-quality layers to assess the quality of the DEM-derived layer).

Now, though, I have encountered the problem of not being able to find a good surficial geology layer for the watershed I'm studying. I'm sure that there must be something out there, but I can't find it. I'll have a talk with some people in the lab once the summer break is over, but I wanted to start on something today. Well, after a rummage around, I found nothing usable, and so I turned back to the central source of GIS data layers that I used for my master's research: VMAP0.

Although it's somewhat old (and that's an understatement), VMAP0 does provide a decent (if somewhat coarse-resolution) data source for those data layers that don't change too quickly over time (like geology). One thing that I had forgotten was that VMAP0 is in a file format that I can't use in QGIS (which is the GIS program I'm using while I wait for the summer break to be over and I can get someone from IT to set up a remote connection to the university's license server).

Well, after a couple of searches, I found that someone had already converted all the VMAP0 regions into "shapefile" format. Harasho to the guys at GIS-lab!

EDIT: ... and it turns out that VMAP0 actually doesn't have geology layers. Darn. Well, back to the search.

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