GIS Portfolio: Ross Wygmans

Rasters are one of the two primary data models used in GIS. While vectors use points and line segments to identify locations on Earth, rasters define space using a matrix of equally sized cells. Two modules included within the ArcPy package allow access to many geoprocessing tools designed to work with raster data and imagery, which is a specific type of raster data. These modules are the Spatial Analyst ( arcpy.sa ) and Image Analyst ( arcpy.ia) modules.  Our task for this week's lab was to write a script that creates an output raster layer identifying areas that fall within a given set of parameters regarding slope, aspect, and land cover class. More specifically, the output layer had to identify areas with the following characteristics:  Forest land cover (classifications 41, 42, and 43) Slope between 5°and 20° Aspect between 150°and 270° Below is a flowchart which outlines the various steps of the script. One challenge I had while writing the script was trying to assign b...

Points, lines, and polygons are all examples of geometry objects. Each of these geometries consist of one or more vertices, or pairs of x,y coordinates. Understanding how to read existing geometry objects and how to create new geometry objects using the ArcPy package within Python provides detailed manipulation of features and the vertices of which they are composed.  Our task for this week's lab was to write a script that creates a .txt file and writes to it the Object ID, Vertex ID, x - y coordinates, and the name of the feature associated with each vertices contained within a shapefile called "rivers.shp".   Pseudocode is a plain language description of the steps within a program or algorithm. Writing out the pseudocode before attempting to write the actual script can be helpful in developing and understanding the structure or outline of the script. Below is an example of pseudocode for the script in this week's lab.  Start           ...

Two of the most common methods for exploring data are through the Describe() function and the ListFeatureClasses() function within the arcpy package. The  Describe() function allows one to explore the properties of a particular dataset, such as data type, file path, base name, etc., and  the  ListFeatureClasses()  function creates a list of all feature classes within the current workspace. Tabular and spatial data can be manipulated with the use of cursors, which allow one to iterate over the records in a table or insert new records. There are three types of cursors, namely search cursors, insert cursors, and update cursors.  In this weeks lab, we used the  ListFeatureClasses()  and  Describe()  functions to copy all the features in our Module 4 Data folder into a new file geodatabase. We then used a search cursor to locate all the county seats of New Mexico within the "cities" feature class and printed the name, population, and featu...

One of our tasks for this week's lab was to write a Python script using the Spyder IDE to execute the following geoprocessing objectives on the provided hospitals shapefile :  Add XY Coordinates to the hospitals shapefile Create a 1000 meter buffer around the hospital feature Dissolve the hospital buffers into a separate, single feature My thought process for completing these objectives is outlined in the following steps:  First, I imported the ArcyPy package, set the workspace environment to my Data folder within the Module 3 folder (S:/GISProgramming/Module3/Data), and enabled geoprocessing outputs to be overwritten. For adding the XY coordinates to the hospitals shapefile, I ran the AddXY_management() tool using the hospitals shapefile as the input parameter. I then used the GetMessages() function to print out the messages from this tool.  For adding the 1000 meter buffer around the hospitals, I ran the Buffer_analysis() tool using the hospitals shapefile as the input...