GIS 520 Spatial Problem Solving

Data Cardinality



Working for a state commerce agency, you are asked to report the number of jobs created in each Senate and House district. You are given recent data from an industrial extension jobs survey to complete this task. The problem is centered around how to get the data you need from several different resources when the relationship between data are not always singular, i.e. one-to-many or many-to-one with tabular or spatial joins.

Analysis Procedures

First you need to look for what information/fields you need from each data set and see what kind of object identifier is present. Go through and select only the data you need using select by attribute, eliminating any data outside of NC. You then have to decide the best way to join the data with the Senate and House district shapefiles. For this problem, a spatial join was used.




















Senate Job Creation Map                                     House Job Creation Map
















Problem Description

More sweet potatoes are grown in NC than in any other state. The client wants to know the number of sweet potato farms located in each county in NC and which of these farms are located in voluntary agriculture districts (VAD).

Data Needed

Industry data from the Bureau of Labor Statistics, counties of NC shapefile and voluntary agriculture districts of NC Shapefile.

Analysis Procedures

The first thing you need to do is limit your geographic area to NC. In case some of the districts go over state lines, you need to clip the area to NC only. When looking at sweet potato growers in NC, the BLS data is calculated by the number of growers per county. This data should be converted to a point file based on address. Once this has been done you need to figure out what kind of join you'd need with the  NC /VAD shapefile. In this case a spatial join would be proper.