Exercise 5 - Data Gathering

Introduction - This exercise was focusing on gathering data and we used land cover data for Trempealeau County as an example. There were four steps to this process; downloading the data, importing and joining the data, and then writing a script to project and clip the data.

Data gathering – We downloaded the data from multiple websites:

-          Rail line feature classes from the US Department of Transportation website.

-          An elevation map from the USGS National Map site.

-          An agricultural use map from the USDA Geospatial Data Gateway.

-          Trempealeau County land records from the Trempealeau County Land Records site.

-          Soil information from the USDA NRCS Web Soil Survey.

The websites all gave the data in zipped files and I then extracted them into a common folder. Next I needed to join the attribute tables from the soil survey and the Trempealeau County geodatabase in order to normalize the projection and join the soil information into the land use record. I imported SSURGO data from Microsoft Access in order to join the tables which included a common key for the data to join correctly.

To put the data into a neat map I wrote a Python script which can be seen in the Python scripting blog post under exercise 5. This clipped the data into just the county of Trempealeau and projected the data into the correct projection. It also loaded the finalized feature class into the Trempealeau geodatabase. The resulting map is shown below, incorporating all of the downloaded data into one poster.

Data Accuracy – The table below shows parameters from the metadata for each of the separate data records that were downloaded.

Record	Scale	Effective Resolution	Minimum Mapping Unit	Lineage	Temporal Accuracy
Rail Lines	1:24000	30m	30m	US Department of Transportation	2014
NLCD	1:24000	30m	30m	USGS	2011
DEM	1:100000	10m	10m	USGS	2013
NASS	1:100000	30m	30m	USGS	2013
Trempealeau	1:24000	30m	30m	Trepealeau County Land Records	2014

(See Python Blog Post for Python potion of this exercise.)

Sources:

US Department of Transportation Bureau of Transportation Statisics Link

USGS National Map Viewer Link

USDA Geospatial Data Gateway Link

Trempealeau County Land Records Link

USDA NRCS Web Soil Survey Link