Geoprocessing

This week we started to apply our python knowledge within ArcGIS itself.  Using scripting can make doing actions much faster and less monotonous than doing everything manually.

In the first part of the lab, we used ArcPro's model builder to create a multistep process that outputs a shapefile.  With the model builder you can drag and drop files and tools and combine them to preform actions in a certain order.  For our lab we made a clipping of all the soils within the extent of a basin.  Then simultaneously used the select tool to pick out all the soils that were classified as "not prime farmland" with a SQL query.  Lastly, we used the generated not prime farmland shapefile to erase from the soils within the file clipped from the basin.  This created a final product where all the good farmland within the basin area remained.

For the second part of the lab, we shifted gears and used the Spyder IDE.  There were three primary goals of the program I wrote: assign XY coordinates to a hospitals shapefile, create a 1000m buffer around those hospitals, and create a dissolved 1000m buffer around the hospitals.  This entailed importing the arcpy module to the freshly created script.  Then I set the workspace environment and set it so it was possible to overwrite output files which made it much easier to re-run scripts over and over while tweaking them.

Adding the XY coordinates to the hospitals was a matter of just running the appropriate module with the correct shapefile fed into the parameter.  The buffers were somewhat more involved since they take more parameters.  The first buffer needed three parameters: the file to create the buffer around, the path of the output file, and the size of the buffer itself.  The dissolved buffer took and extra three parameters, two of which were left blank since they don't apply to this situation and the last one set to 'ALL' so that the buffers would dissolve.  A dissolved buffer is were any overlap between buffers is combined so that the outputted polygons and melded together.

Lastly, I used the GetMessages module with stated the start time of each procedure, if it was successful, and how long each method took.  This shows that the program ran correctly, though I also double checked in ArcPro itself.

The program that gave the hospitals shapefile XY coordinates and also created the buffer layers successfully running.

Overall, I thought scripting would be much more intimidating for someone with a minimal computer science background.  I see how even fairly straightforward applications of Python can make doing operations in ArcGIS much easier as well as faster and I look forward to learning more applications.