This week's module focused on accuracy assessment. We were tasked to analyze the completeness of two Oregon road networks, one sourced from Jackson County GIS, and the other sourced from the U.S. Census Bureau's TIGER shapefile. This module defines completeness as the measure of the lack of data and the comprehensiveness of the dataset in representing real-world objects (Haklay, 2010).
In order to perform the completeness analysis, I first used the clip tool on the centerline shapefiles in order to remove any road segments outside of the county grid. Then I used the Summarize Within tool to calculate the centerline length totals by grid. This tool allowed for the total lengths to be calculated for road segments contained within their respective grid polygons.
Positive % difference indicates that the Jackson County GIS dataset had a greater coverage, whereas a negative % difference indicates that the TIGER dataset had the greater road network coverage.
Afterwards, I used the Table to Excel tool to export the summarized grid features in order to calculate a numerical summary of the results. I used the Calculate Geometry tool to obtain the area of a grid cell.
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