1. GIS Topics and Applications
GIS Modeling
GIS Topics and Applications

2. 5 Ms of GIS
Mapping
Measurement
Monitoring
Modeling
Management

3. Geoprocessing
When we perform geoprocessing tasks on our data, we are developing the components of a GIS model.
We perform geoprocessing every time we:
Use a tool interactively in ArcMap
Use tools from ArcToolbox
Execute commands using the command line
Connect tools in ModelBuilder
Use functions in a script (like Python)

4. Static and Dynamic
Static modeling is the series of steps required to achieve some final result.
Available land for development of a nursery
Siting of cell towers
Dynamic modeling is performed in a similar fashion, but has additional parameters requiring several iterations of the model.
Disease outbreak modeling
Real-time traffic analysis
Spread of wildfires, heavy rain, etc.

5. Why Model?
Developing a model for a GIS analysis allows for repeat testing of a hypothesis using different data.
The model can be coded into a GIS application, so that the steps are performed automatically.
Easier reproduction of results.
Simplification of workflow.
Informs the computer how to conduct a series of steps that would be impractical for you to do manually.

6. Reproducibility
In performing an analysis, you must have your workflow clearly defined.
This ensures that you are performing the steps in the correct order using the appropriate tools.
Missteps are easy, especially when there can be hours of computer processing between steps.
The GIS model can be exported as a graphic flowchart or a modeling data structure.

7. Workflow Efficiency
There are many repetitive steps you will take in your daily workflow.
Streamlining the process saves you time.
If you always start working in a File Geodatabase with specific resolution and projection information, a model for generating your specialized GDB can be created.

8. Human Inefficiency
You physically cannot perform the steps as fast as GIS can produce the results.
Certain steps, such as iteration through a feature set would be prohibitively time consuming.
You must perform the same steps 21 times to clip data to each individual NJ county.
Rail use analysis: 200+ stations
Minimize the amount of time spent “babysitting” GIS to perform complex analyses.

9. How do we model?
ArcGIS has a drag-and-drop interface to ArcToolbox called ModelBuilder allowing you to develop a flow chart of your GIS workflow.
This flowchart is then run step by step to perform your analysis.
ArcGIS allows for custom scripting that can be added to ArcToolbox, introducing greater functionality.
Custom export scripts, specialized versions of existing tools, develop tools not available in ArcToolbox.

10. ModelBuilder

11. Introduction to ModelBuilder
Over the past semester, we've performed several geoprocessing tasks
We have used geoprocessing tools in sequence to analyze GIS data
ArcGIS allows you to link tools together to create a workflow

12. Homework Flashbacks
You have a set of points, that you want to clip to a county, then find the count of points that fall within each municipality
You have a statewide layer you want to clip to a specific feature, then dissolve
ModelBuilder will allow you to select features, perform tasks like clip, spatial join, merge, etc…

13. Inside ArcToolbox

14. Inside ArcToolbox
Models and Scripts are added to custom toolboxes you create in ArcToolbox.
Toolbox
Toolset
Script
Model

15. Creating a New Toolbox
Creating your own Toolbox is not just for organizational purposes. It allows you to share your models with others.
If you will be sharing your model and using relative addresses, you need to plan the folder location of your New Toolbox carefully.
Default location for a New Toolbox created inside ArcToolbox is: C:\Documents and Settings\<user profile>\Application Data\ESRI\ArcToolbox\My Toolboxes.
Create a new Toolbox by right clicking in ArcCatalog and selecting New Toolbox.

16. How ModelBuilder Works
Drag layers you want to participate into the model
Drag tools you want to use into the model
Output layers, tables, objects shown in green
Connect the features using arrows
Order matters to certain tools (Clip)

17. Revisiting Assignment #3
In this assignment, we selected the municipalities in Gloucester County
We then selected the KCS within the Gloucester County municipalities
Finally, we performed a spatial join on the two layers to find a count of KCS within each of the municipalities

18. Getting Started Let's make a new Toolbox to store our models
Make a new model inside the Toolbox
Edit the model

19. Drag and Drop Interface

20. Order Matters

21. Order Matters 1 2

22. Order Matters 2 1

23. Final Model

24. Multiple workflows in one Model
reclassed road distance
non-floodprone layer
residential and wetlands plus buffer

25. Additional Functionality
The Model can be expanded further, with more data and tools
The Model can be exported into a scripting language, allowing for greater modeling capabilities.

26. Additional Functionality
Python is the default (and recommended) scripting language for ModelBuilder
Cursor-based analysis: For each individual feature in a layer, perform some analysis
For each "vacant" polygon, is it surrounded by environmentally sensitive features?
Count each feature's vertices, rings
Internet access: automatically download data, then analyze

27. Going Further A ModelBuilder Overview Available on ESRI's support page
Getting Started Writing Geoprocessing Scripts Available on ESRI's support page
Dive Into Python
Learning Python, 3rd Edition