Module 9 - Working with Rasters

This assignment taught us to work with rasters using Python. We worked with 2 rasters, elevation and landcover, to create a Python script is a single raster image with the following criteria: 1) Forest landcover classification; 2) slope between 5 and 20 degrees; and 3) aspect between 150 and 270 degrees.

It is becoming almost habit to start off by importing the necessary modules needed for the script and to set the overwrite output to true. For this assignment, I attempted to create the output in a .tif format, but I got several errors, so I went with the optional part and created a file geodatabase. For the rest of the script, the module exercise was extremely helpful and relevant to the assignment. I created a conditional statement so the script would only run if the Spatial Analyst extension was available. Further down toward the end of the script, there is an else statement printing a message if it is not available. Within the if statement is where the bulk of the script is located, as I only want it to run if the spatial analyst module is available. I used the remap value and reclassify tools to reclassify the landcover raster so that only the forested areas are given a value of "1". I assigned the elevation raster to a variable and used the slope and aspect functions to create temporary rasters of those types. I was impressed with how user friendly the map algebra commands are when used in Python, so performing the slope and aspect calculations weren't an issue. I created temporary rasters based on the 3 criteria listed above and using "less than" and greater than" statements in the script. I combined the 5 rasters (four slope and aspect rasters and the reclassified landcover raster), and saved it to make it a permanent raster. Below is a screenshot of the raster, with the "0" (reddish-brown in color) signifying areas of the landcover raster not classified as forest and areas labeled as "1" (the green areas) showing areas that are forest land cover.

This assignment was far less stressful for me than last week's assignment. I feel I have a greater understanding of this concept, and the exercise was extremely helpful, so if I had a syntax error I could look at the exercise (and the textbook) to determine if I was missing a parentheses or whatever the error was. The only issue I had dealt with the file geodatabase I created. Even setting the overwrite output to true does not allow you to overwrite the geodatabase, which I suppose makes sense. The geodatabase has files within it, and you usually can't overwrite a non-empty folder. I was unable to find any workaround, so after running the program once, you still have to go into the Results folder and delete the geodatabase. I didn't do this as it just occurred to me while writing this, but I wonder if it's possible to have the code delete the files within the geodatabase at the end of the script, and then have Python overwrite the empty geodatabase. I liked working with rasters in this assignment and I was impressed that Python almost seems to be made to work with some of the map algebra operators. I like that a relatively short and simple code can do this much geoprocessing. On another note, the ELearning site appears to be down, so I chose to email the instructor the relevant deliverables.