GIS Portfolio

Subtitle

Python Scripting

I have worked on GIS Projects that involved simple to complex geoprocessing. These projects involving spatial analysis were streamlined using Python Scripting. 

An example of the Scripting Tool that was published on ArcGIS Online is shown below. 

                       Population Potential Index - Script Tool

Summary: - The Population Potential Index is an accessibility measure from a given point. The concept of Population Potential holds very important place in geography and regional science as a basic index of spatial accessibility and relative location. This measure is useful and possibly a determining factor when making an ideal site selection. For example, a sales location for Women’s Clothing or a placing a new Senior Health center. Currently, there is no geoprocessing tool or model available that can calculate this index. The purpose of building this geoprocessing tool is to provide a streamlined approach that utilizes Network Distance not Euclidean Distance to calculate the Population Potential Index for a given point to make the ideal site selection.
About Population Potential Index:-
As described earlier the Population Potential is an accessibility measuring index from a given point. So, mathematically it is,
PIndex = Population (Pi) / Distance (Di)
Where,
Pi = Population in a specified area
Di= Distance from the Population in a specified area to the Given Point – Network Distance
How this tool works and used:-
Please see the following example that explain how this tool works and used. This is a hypothetical example. 
Problem: - After carrying out an initial capital facility analysis the city planning agency realized that there is an area of a city that is under served by particular public facility – Library. The graphic below shows the 1 mile service area polygon for each library in the City of Philadelphia. As you can see there is a region for which there is no coverage for the facility highlighted in the graphic. 




Now, after studying the region which is underserved by the facility, talking to the local stakeholders and city agencies, the city planning came up with possible three sites for the facility (graphic shows on the right). All three sites are identical with not much difference in the overall land acquisition and construction cost. So, which site is the most suitable? City Planning learned about the population potential index and excited to apply this concept to this problem to make sure the new facility is placed in an ideal location with an excellent accessibility.  
Using this tool they can find out the index for all three locations within minutes. Now, the GIS person will input the following required dataset as shown in the screenshot of the tool on the next page,


Following GIS Dataset is required for calculating the Index using this Tool:-
A) Road Network Dataset
B) Polygon Layer (Census Block, Census Block Group, or Census Tracts) with Population Attribute
C) Facility Layer

 
As you can see in the above the screenshot user inputs,
A) The point feature class consisting site layer   
B) Select “SITE A” using SQL expression from the site layer
C) Inputs the Streets Network Dataset
D) The Scratch Workspace 
E) Inputs the Census Blockgroup Layer as a Polygon Layer
F) Selects the Population attribute field from the Census block group layer
G) User Inputs the distance of “1 mile”
H) User Select the distance unit as Miles. The default is feet.
I) User selects the location and the name of the Service Area Analysis layer will be created
J) Lastly, user selects the output Population Potential Layer which is a line feature class connecting the site to the Centroid of the Census block group. Also, the attribute field contains the network distance, population of each Census block group and population index for each Census block group located within 1 mile of the facility. 
After running the analysis for all three sites the GIS user finds that,
Population Potential Index for Site A, Site B and Site C are 9.074, 8.659 and 9.534 respective as shown below in chart,
 

Clearly, the SITE C has the highest index for 1 mile among all the sites. Thus, SITE C an ideal location when considering the Population Potential Index. 
Implementation Details:
This tool is written as a script tool in Python. 
Software Requirements:
ArcGIS 10.0 or later 
ArcView (Basic) license or higher
ArcGIS Network Analyst Extension
Summary: - The Population Potential Index is an accessibility measure from a given point. The concept of Population Potential holds very important place in geography and regional science as a basic index of spatial accessibility and relative location. This measure is useful and possibly a determining factor when making an ideal site selection. For example, a sales location for Women’s Clothing or a placing a new Senior Health center. Currently, there is no geoprocessing tool or model available that can calculate this index. The purpose of building this geoprocessing tool is to provide a streamlined approach that utilizes Network Distance not Euclidean Distance to calculate the Population Potential Index for a given point to make the ideal site selection.
About Population Potential Index:-
As described earlier the Population Potential is an accessibility measuring index from a given point. So, mathematically it is,
PIndex = Population (Pi) / Distance (Di)
Where,
Pi = Population in a specified area
Di= Distance from the Population in a specified area to the Given Point – Network Distance
How this tool works and used:-
Please see the following example that explain how this tool works and used. This is a hypothetical example. 
Problem: - After carrying out an initial capital facility analysis the city planning agency realized that there is an area of a city that is under served by particular public facility – Library. The graphic below shows the 1 mile service area polygon for each library in the City of Philadelphia. As you can see there is a region for which there is no coverage for the facility highlighted in the graphic. 




Now, after studying the region which is underserved by the facility, talking to the local stakeholders and city agencies, the city planning came up with possible three sites for the facility (graphic shows on the right). All three sites are identical with not much difference in the overall land acquisition and construction cost. So, which site is the most suitable? City Planning learned about the population potential index and excited to apply this concept to this problem to make sure the new facility is placed in an ideal location with an excellent accessibility.  
Using this tool they can find out the index for all three locations within minutes. Now, the GIS person will input the following required dataset as shown in the screenshot of the tool on the next page,


Following GIS Dataset is required for calculating the Index using this Tool:-
A) Road Network Dataset
B) Polygon Layer (Census Block, Census Block Group, or Census Tracts) with Population Attribute
C) Facility Layer

 
As you can see in the above the screenshot user inputs,
A) The point feature class consisting site layer   
B) Select “SITE A” using SQL expression from the site layer
C) Inputs the Streets Network Dataset
D) The Scratch Workspace 
E) Inputs the Census Blockgroup Layer as a Polygon Layer
F) Selects the Population attribute field from the Census block group layer
G) User Inputs the distance of “1 mile”
H) User Select the distance unit as Miles. The default is feet.
I) User selects the location and the name of the Service Area Analysis layer will be created
J) Lastly, user selects the output Population Potential Layer which is a line feature class connecting the site to the Centroid of the Census block group. Also, the attribute field contains the network distance, population of each Census block group and population index for each Census block group located within 1 mile of the facility. 
After running the analysis for all three sites the GIS user finds that,
Population Potential Index for Site A, Site B and Site C are 9.074, 8.659 and 9.534 respective as shown below in chart,
 

Clearly, the SITE C has the highest index for 1 mile among all the sites. Thus, SITE C an ideal location when considering the Population Potential Index. 
Implementation Details:
This tool is written as a script tool in Python. 
Software Requirements:
ArcGIS 10.0 or later 
ArcView (Basic) license or higher
ArcGIS Network Analyst Extension

 

Name of the Tool: - Population Potential Index

This tool is published on arcgis.com :- 

http://www.arcgis.com/home/item.html?id=aa1517232ee04870915a9222fac7e7c9

Summary: - The Population Potential Index is an accessibility measure from a given point. The concept of Population Potential holds very important place in geography and regional science as a basic index of spatial accessibility and relative location. This measure is useful and possibly a determining factor when making an ideal site selection. For example, a sales location for Women’s Clothing or a placing a new Senior Health center. Currently, there is no geoprocessing tool or model available that can calculate this index. The purpose of building this geoprocessing tool is to provide a streamlined approach that utilizes Network Distance not Euclidean Distance to calculate the Population Potential Index for a given point to make the ideal site selection.

About Population Potential Index:-

As described earlier the Population Potential is an accessibility measuring index from a given point. So, mathematically it is,

PIndex = Population (Pi) / Distance (Di)

Where,

Pi = Population in a specified area

Di= Distance from the Population in a specified area to the Given Point – Network Distance

How this tool works and used:-

Please see the following example that explain how this tool works and used. This is a hypothetical example. 

 

Problem: - After carrying out an initial capital facility analysis the city planning agency realized that there is an area of a city that is under served by particular public facility – Library. The graphic above shows the 1 mile service area polygon for each library in the City of Philadelphia. As you can see there is a region for which there is no coverage for the facility. 

 

Now, after studying the region which is under-served by the facility, talking to the local stakeholders and city agencies, the city planning came up with possible three sites for the facility (graphic shown above). All three sites are identical with not much difference in the overall land acquisition and construction cost. So, which site is the most suitable? City Planning learned about the population potential index and excited to apply this concept to this problem to make sure the new facility is placed in an ideal location with an excellent accessibility.  

Using this tool they can find out the index for all three locations within minutes. Now, the GIS person will input the following required dataset as shown below the screenshot of the tool,

Following GIS Dataset is required for calculating the Index using this Tool:-

A) Road Network Dataset

B) Polygon Layer (Census Block, Census Block Group, or Census Tracts) with Population Attribute

C) Facility Layer

 

 As you can see in the above the screenshot user inputs,

A) The point feature class consisting site layer   

B) Select “SITE A” using SQL expression from the site layer

C) Inputs the Streets Network Dataset

D) The Scratch Workspace

E) Inputs the Census Blockgroup Layer as a Polygon Layer

F) Selects the Population attribute field from the Census block group layer

G) User Inputs the distance of “1 mile”

H) User Select the distance unit as Miles. The default is feet.

I) User selects the location and the name of the Service Area Analysis layer will be created

J) Lastly, user selects the output Population Potential Layer which is a line feature class connecting the site to the Centroid of the Census block group. Also, the attribute field contains the network distance, population of each Census block group and population index for each Census block group located within 1 mile of the facility.

After running the analysis for all three sites the GIS user finds that,

Population Potential Index for Site A, Site B and Site C are 9.074, 8.659 and 9.534 respective as shown below in chart,

Clearly, the SITE C has the highest index for 1 mile among all the sites. Thus, SITE C an ideal location when considering the Population Potential Index.

Implementation Details:
This tool is written as a script tool in Python.

Software Requirements:

ArcGIS 10.0 or later 

ArcView (Basic) license or higher

ArcGIS Network Analyst Extension