GEOG 5222 Project 1

Decision Support with a GIS

by Tom Wells -  July 2003

The first class project provides a data set and instruction for locating a "Jen and Barry's Ice Cream" business.  The site selection exercise begins with 48 cities in the area of interest covering 43 counties.  ESRI's ArcView 8.3 is used with the following attribute and geospatial criteria to select some of the cities for further consideration: 

1. Business Criteria

   1. Greater than 500 farms for milk production

   2. A labor pool of at least 25,000 individuals between the ages of 18 and 64 years

   3. An interstate within 20 miles
      

2. Quality of Life Criteria

   1. A low crime index (less than or equal to 0.02)

   2. At least one recreation area within 10 miles

   3. A population of less than 150 individuals per square mile

   4. A location near a university or college

 The first data cut can be made with the County layer based on the following attribute criteria: 

Criteria A.1;  NO_FARMS87 > 500, and
Criteria B.3;  POP_SQMILE < 150, and
Criteria A.2;  AGE_18_64 >= 25000

Only 11 counties out of the 43 meet the above criteria.  Just about any data query tool could process this simple single table, three criteria query.  However, a GIS is required to determine which of the 48 cities fall within the 11 counties (because the county boundaries are irregular polygons).  ArcView 8.3 was installed for this class, a state-of-the-art GIS with both attribute and geospatial based data selection capabilities.  Note: 17 of the 48 cities fall within the 11 counties (as saved as layer CitiesQuery1).  

The second data cut can be made with the city attribute data table:

Criteria B.4;  UNIVERSITY = 1
Criteria B.1;  CRIME_IND <= 0.02

Just 9 of the 17 remaining cities meet these two criteria (CitiesQuery2).

Criteria A.3 also requires a GIS spatial query.  Just 7 of the 9 remaining cities are within 20 miles of an interstate (CitiesQuery3).  Note: this is NOT the same as being within 20 miles of an interstate interchange.  Toll roads (like the Pennsylvania Turnpike) often have a very limited number of access points.

The remaining criteria, B.2; "at least one recreation area with 10 miles", is a spatial query.  Only 4 of cities make the final cut (CandidateCities) as shown in figure 1 via the large stars.

Project 1 required deliverable showing 4 cities that meet the specified criteria.  Note: The relatively straight southern boundary of the mapped area is approximately 220 miles long.

Optional Material

Two additional data layers, hydrology and landmarks, are added to the data set for further consideration.  The following geospatial criteria are selected to narrow the list of potential cities to those.

• Within 10 miles of a river or lake, and

• Within 40 miles of a landmark

Figure 1 does not include any data selection subsets in that selected data is saved as new layers and layers are either totally on or off.  Conversely, the following figure shows two data subsets within two layers; Hydrology and CandidateCities.  The hydrology data set is restricted to rivers and lakes as shown by the bright turquoise highlighting that thickens the hydrology features.  (The un-highlighted hydrology features are mostly "streams".)  

All of the 48 cities in all 43 counties are also shown in Figure 2.  Most of the cities are indicated by dark blue squares.  Based on the two additional criteria, only one city of the four CandidateCities meets all of the selection criteria.

Figure 3:

Only one of the four Candidate Cities meet the extra Hydrology and Landmark criteria.

GEOG 5222 CD-R, WCGIS\Lesson1\ Dataset 

Hydrology and Landmark data set, www.e-education.psu.edu/courses/geog5222/zips/exp1files.zip,  Downloaded 6 July 2003