Where can I get the coordinates datasets of water bodies of a country?

Question

I'm in need of acquiring the coordinates of the outlines of all the water bodies inside a country, with the exception of "Sea" or "Ocean" water. Right now, I'm manually outlining the lakes and rivers but it is not a sustainable solution for the magnitude of the research I'm doing.

Even if I can only obtain the data of Lakes or Rivers, that would be a great start. I'm specifically interested in the countries of Malaysia, Brazil, and the Dominican Republic.

My situation brings me to the question of, where does Google Maps obtain its data? Are these data sets available?

Answer 1

I don't know of any sites where you'll find pre-existing lists or databases with coordinates for the shapes of water bodies. Most gazetteers will only give you coordinate centroids, or bounding boxes at most. However, it's relatively easy to generate this data from shapefiles or KML files using desktop GIS software. There's a lot involved with learning GIS, but if this operation was all you need to do it's straightforward.

You can download an open source desktop package like QGIS: http://qgis.org/en/site/ and then as another post suggested, you can download shapefiles for water features from a site like Natural Earth. The shapefiles consist of geometry - strings of coordinates stored in a specific format - so they can be represented visually in the software. If you add the water shapefile to the GIS software, you can export the shapefile out as a CSV and generate the underlying coordinates for each feature out into a text format.

Essentially:

1. Download and unzip the shapefile
2. Launch QGIS and add the shapefile as a vector file
3. Select it in the layer list, right-click, save as
4. In the Save As menu, save it as a CSV, and under layer options, Geometry, select AS_WKT
5. Hit OK - if prompted select WGS 84 as the coordinate system (assuming the file is from Natural Earth)

There are a number of posts on the GIS stack exchange like this one: https://gis.stackexchange.com/questions/8844/get-list-of-coordinates-for-points-in-a-layer that also show how you can accomplish this.

Answer 2

Have you checked out Natural Earth? They have some shapefiles for rivers, lakes, and reservoirs:

http://www.naturalearthdata.com/downloads/10m-physical-vectors/

Answer 3

See the other GIS Stackexchange where you might find very useful

https://gis.stackexchange.com/questions/182944/where-to-find-a-polygon-shapefile-of-countries-states-and-islands/182961#182961