Goal
The goal of this assignment was to become familiar with the process of downloading data from different sources on the internet, importing the data to ArcGIS, joining the data, projecting the data from these different sources into one coordinate system and building and designing a geodatabase to store the data. Finally, create maps showing our results of our python script that we wrote to accomplish the previous actions.
Methods
In this assignment, data collection was a huge section. The first half of the assignment was going out to different sources on the internet and downloading data sets from them. These were all government sites, so we know that they are all trusted data sources. Before we started downloading data, I went ahead and set up my data management. I made sure that I had an exercise 5 folder and a working folder inside of that. The TEMP folder on the university computer was used to hold the initial downloaded zip files. From there, they were extracted and put into our working folder which was further broken down into folders for each website where data was downloaded from.
The first site that we visited was the US Department of Transportation. They supplied a transportation data set. In that data set were things from railway and road files. The AOI that was used was Trempealeau County. The next site that provided data was the USGS National Map Viewer. This provided data for the land cover of the Trempealeau County area. The two DEM rasters that resulted in one of our final maps was from this site. The next site was the USDA Geospatial Data Gateway. From this site, I obtained information on Trempealeau Counties cropland data layer. The source of data was directly form the Trempealeau County land records them self. This was probably the most important piece of data. It contained an entire geodatabase of the county and all of its relevant data. The last site that was used was the USDA NRCS web soil survey. This site provided another of the rasters that will be shown in the results.
After the collection of data, it was time to import the SSURGO Data that we got from the soil survey. These were a large collection of tables. To import it, we used Microsoft Access. It imported it to a format that could be used in ArcMap. Next, I created a python script that was used to project, clip, and load all the data into the geodatabase. The script brought in all of the rasters that we gathered from the data sources, put them all in an appropriate coordinate system and then clipped them to the shape of the Trempealeau County border. Figure 1 below is a screenshot of the script that was run.
figure 1. Python script used to project clip and load collected rasters into the geodatabase.
Data Accuracy
Final Maps
Conclusion
After completion of this assignment, I think that I have gotten a much better idea of how gathering data can be both extremely helpful and sometimes very frustrating. I am glad that we got to experience going out on the internet and gathering real data from different government sources. The use of python for basically the first time also shined a light on the many different ways to accomplish tasks in ArcMap and GIS in general.
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