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1

1) you don't need to export a shapefile. With the Python module GDAL (osgeo) you can read directly the layer from the GRASS folders hierarchy (look at GRASS 6 terminology) from osgeo import ogr # open the Grass layer shape1 ds = ogr.Open('/Users/grassdata/geol/MNT/vector/shape1/head') layer = ds.GetLayer(0) ... 2) If you want to read the shapefile, you ...


3

Your main question title indicates you're looking at sea level and coastal areas. But we'll start at the bottom of your question and work backward. Consider lakes and rivers. Many of them may be significantly above sea level, even their bottoms, thus relying on elevation alone in the DEM cannot tell you if an area is water or not. Plus in a DEM large water ...


0

This answer is probably a little late, but hopefully better than never. William Huber came up with an answer a couple years ago and I implemented it as a model in Model Builder. See the following tool - http://www.arcgis.com/home/item.html?id=40d33968c44e4c9395c9c1ff1edd2bbe and blog post - ...


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I've got a sinuosity and gradient toolbox that you may end up wanting to take a look at - http://www.arcgis.com/home/item.html?id=c8eb4ce1384e45258ccba1b33cd4e3cb


2

Watershed straight edge is usually clear indication of processing extent being not large enough. I guess that dams extent affected result shown. Output of watershed tool http://resources.arcgis.com/EN/HELP/MAIN/10.2/index.html#/Watershed/009z00000059000000/ depends on correct value of extent. It is a good idea to set your extent to DEM extent, set cellsize ...


5

In the world of hydrology and geomorphology, there is indeed a metric that we use to classify/quantify the "curviness" of a river......sinuosity. Sinuosity is simply a measure of the actual path length of the river divided by the shortest path length (straight line distance). So, you could measure the sinuosity of the river as a whole (actual path length ...


2

I'm not a hydrologist, so I'm not aware of any metrics/heuristics that should likely govern your methods, but here's a stream-of-consciousness response for something that would be fun to try. Interpolate points along the line: First, I'd interpolate points along the line with an equal-length, short spacing according to a minimal granularity where the ...



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