1. Designing a Spatial/GIS Project
2/10/2017

2. Research Question Does your question involve a geographic element?
How is spatiality part of your RQ?
Data source v variable in itself?
Demographic data v how boundaries impact population
What are you trying to study?
Avoid ecological fallacies
A visual representation of geographic data extracted for a typical research project

3. Scope of Study and Unit of Analysis
Consider what type of data you need
(Vector) Point, line or polygon data?
Points useful for events/counts, distance calculations
Points are discrete and have zero dimensions
Polygons are 2D, represent areas, basic unit for census variables (i.e. demographics by county)
At what level do you need the data?
Usually best to go with small units; not always possible
Different levels have different info and precision
Balance efficiency and info available

4. Factors to Consider/Philosophize
How were the boundaries created?
Some boundaries created at random others with purpose
Boundaries drawn at random have similar populations separated by arbitrary line
Good use for Regression Discontinuity Design
Boundaries with purpose will have similar observations within, endogeneity
Use a multi-level model, random effects, robust clustered errors

5. Extracting Data Organized by Geography
Might simply need demographic info organized by geography
Can acquire these data a number of ways;
Use dbf in R (via foreign pkg; read.dbf(“name.dbf”)
Export data as txt or xls file in ArcGIS
Via copyrows or Table to Excel commands
Simply download it from a site that has the info (i.e. social explorer)

6. Obstacles: Switching Between Levels
Might have data points that you would like as part of polygons, or polygons that should be points
For event point data, join onto polygons
For polygon-> points, use a random point generator
(Switch to ArcMaps)
Remember, random generators use a uniform distribution
To acquire the polygons to export, simply insert the 2 relevant layers. Then go to select by location, click the target layer as the layer you would like to export, and the source layer as what is dictating the selection.
To merge points on to polygons, use the spatial join feature. The path of which is:
Analysis tools > Overlay > Spatial join
For fields, target feature is the field one wants to keep as the unit of analysis, join features the point data that will be counted. In the new dataset, “Join_Count” are the number of points per polygon
For random points, file path is:
“Data Management Tools > Feature Class > Create Random Points”
Need to save to gdb; constraining class keeps points inside polygons, click field to generate points per field
Map’s point data entirely generated at random by census block group

7. Analysis Use appropriate methods as has been discussed to date
I.E. Controls for multilevel models, spatial clustering, etc.
Might present primary dependent and independent variables on maps
Do not clutter map too much; every variable adds a new dimension