CEEn 414 - Civil Engineering Applications of GIS

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Learning ArcGIS Spatial Analyst - 2

For this assignment you are to download a 1 arc-second degree DEM data for the area of your choice (or use the same one you downloaded for the previous assignment). I want you to experiment and learn on your own how to use a few additional features (with a few hints).

You need to first delineate a watershed using the hydrology tools in the Spatial Analyst. The order of processing to delineate a watershed is as follows:

1. Fill the original DEM
2. Create a flow direction grid from the filled DEM
3. Create a flow accumulation grid from the flow direction grid
4. Create a new point shape file and then use the editing tools to create a "pour point" or watershed outlet using the flow accumulation grid as a guide to show you where your streams are.
5. Create a watershed grid from the flow direction grid and the pour point shape file.
6. Convert your watershed raster to a polygon shapefile (not really necessary but the review is good). You might also try converting your flow accumulation grid to a line shape file to create streams.

Now with your watershed polygon I want you to calculate "zonal" statistics, which just means using the watershed boundary as a computational domain, for the following:

1. Elevations
2. Slopes
3. Not sure how this will work but do Aspect and Curvature (I really don't know what kind of values are used for these so taking their statistics may not make sense).

Finally using your pour point shape file create another point (or two) and create viewsheds somewhere in your watershed I believe it will create a viewshed for each point, but you might try selecting points and see if it only creates the viewshed for the selected point(s). Overlay it with a hillshade and see if it makes sense

Create a web page using pictures (layouts) to describe what you have discovered.

Email the TA when you are finished and include a link to your assignment.

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