Post 3: Gathering Data

Introduction
The goal of this lab was to become familiar with a few sources for collecting data and to determine accuracy of the data collected. The data collected was for Trempealeau County, Wisconsin. A map of Trempealeau County was created using the land cover, crop cover and digital elevation model data gathered from these different resources (Figure 1). In addition, a table was created to display all the information about each dataset that was available to determine the accuracy of the data.

Methods
The data for this map were collected from various sources:

US Department of Transportation-Bureau of Transportation Statistics:https://www.rita.dot.gov/bts/sites/rita.dot.gov.bts/files/publications/national_transportation_atlas_database/index.html

United States Geological Survey-National Map Viewer: http://nationalmap.gov/about.html

USDA Geospatial Data Gateway:http://datagateway.nrcs.usda.gov/

Trempealeau County Land Records: http://www.tremplocounty.com/tchome/landrecords

USDA NRCS Web Soil Survey:http://websoilsurvey.sc.egov.usda.gov/App/HomePage.htm

SSURGO data from the USDA NRCS Web Soil Survey was not compatible with ArcGIS, so the data tables were reformatted in Microsoft Access and imported into the geodatabase created for this map. Once the Trempealeau County geodatabase was put into a folder titled 'Sub' the desired rasters were clipped and reprojected to the shape of Trempealeau County using Python scripting. The script is displayed in a previous blog.

Data Accuracy

Below is a table (Table 1) that information about various attributes of the different datasets used to create the map. Many of the attributes were not included in the metadata of each dataset.

Table 1. Data Accuracy table.

Results

Below is the map (Figure 1) that was created using the various sources of data collected above. The trails feature class was added from the Trempealeau County geodatabase. The maps weren't created for any purpose other than displaying the collected data.

Figure 1. This map was created to demonstrate the use of data gathered from different sources.

Conclusion

The collection of data was difficult considering each source had different ways of downloading the data. This lab helped to get the GIS class used to retrieving information and that this class was extremely helpful in getting our feet wet. Assessing data accuracy was even more difficult, because not every data source openly displayed the necessary information for this lab. It was very frustrating trying to find the information for every field. It is important and necessary to assess the accuracy of data and this lab showed it.