Raster Map Analysis

Steve Henderson



Straight Line Distance Analysis


A straight line distance analysis shows concentric circles that are of equal distance from the closest high school.


Straight Line Distance


Straight Line Distance Allocation

A straight line distance allocation divides the county into four reigions and assigns every location in the county to the nearest high school.  The straight line allocation is fairly close to the actual districts boundaries shown in red, but the actual districts are influenced by the layout of major roads through the county.


Straight Line Distance Allocation





Road Cost Weighted Raster


A road cost weighted raster was created from existing Local Road and Major Road line files by converting each to raster files, in this case using ObjectID for the value field.  The actual values in the new raster were not important as long as the cells containing a road had a value, since each file was to have its values reclassified.  The Major Road file was  reclassifed into one class all having a value of 1, and all of the null values were changed to 100.  The Local Road values were similarly reclassified to 2 for non-null and 100 for null values.


Weighted Raster


To create a single raster the following raster calculation was used:  WeightRoad = min ( MajRoad , LocalRoad ),

where WeightRoad is the new raster to be created from MajRoad and LocalRoad.  This created new raster file, WeightRoad, shown above consisting of the minimum value available from the other two raster files.  This files was used to create the cost weighted allocation districts below.






Cost Weighted Distance Allocation

The cost weighted distance allocation created from the road analysis created an allocation map very similar to the actual districts.  The actual districts vary only somewhat from the cost weighted allocation because the districts are created from the aggregation of exsiting township and borough boundaries.


Weighted Distance Allocation







Student Age Population Analysis


A school age population estimate was created by converting the point data file to a raster and then using zonal statistics to calculate the number of school age students in each exiting school district.  The map below shows a kernal density estimation crated from this raster point file to get a feel for the high density student population locations and my proposed new high school location in red.  The estimation is as follows:

District Name Estimated Number of Students
Bald Eagle Area School District 2181
Bellefonte Area School District 3487
Penns Valley Area School District 2236
State College Area School District 8484


Student Density


Proposed new High School and Districts

Since the population analysis above showed that the State College Area School District already had more than twice the number of students in it than the other districts and the kernal density estimation above showed that most of the students were in a dense area near the middle of the district, the logical choice was to split the existing district and not to disrupt the other districts at all.  Another restriction on the district boundaries requires the new district to consist of contiguous existing township and borough boundaries, severly limiting the options available.  

I recommend splitting the existing State College Area School District district as shown below into the blue and red districts with the new high school (shown in red) located near the high density student population, probably somewhere near Circleville Road or Valley Vista Drive, major roads that would provide easy access from the other two dense clusters to the west.  The existing school can serve the high density central core of the district and what appear to be growing subburbs to the east.


Proposed New High School


Information on where new subdivisions are being constructed would help in determining the best location of the new school, the high growth areas may not relate directly to areas that currently have high density school age populations.  Also, more information on the capacity of the existing schools might affect the decision, if the State College Area High School has enough capacity, you might want to move the new school to help another school that does not.