During Module 3, we worked on an assignment which focused on assessing the completeness of two road networks in Jackson County, Oregon. We were provided with TIGER roads and Centerline road files for analysis. TIGER or Topologically Integrated Geographic Encoding and Referencing has been an important part of the United States' spatial data framework since the 1980s. TIGER has had accuracy challenges over the years, but has been steadily improving. For example, in the "Positional Accuracy of TIGER 2000 and 2009 Road Networks" research article authored by Zandbergen, Ignizio et al., TIGER 2009 was more accurate when it came to urban locations by a factor of two, when compared to rural areas.
When conducting an initial assessment of the length of both road networks for the Module 3 Lab, it appeared that TIGER roads are more complete. We were also provided with a grid for the entire county and asked to determine how many segments from TIGER Roads and Centerlines are contained within each grid. Then we were required to determine the length differences between the two road sets for each grid polygon. Although I figured out how to this inside of ArcGIS, I utilized Excel to manually validate my calculations. My calculations showed that the Center_Lines actually had more segments per grid, than TIGER roads.
No comments:
Post a Comment