Module 5: Exploring & Manipulating Data

 

*Click to enhance*

• Start → (Oval) "Begin Script"
• Set Workspace → (Rectangle) "Define workspace & enable overwrite output"
• Create File Geodatabase → (Rectangle) "Create Mod5A_SKulik.gdb in Results folder"
• List Feature Classes → (Parallelogram) "Retrieve and print all feature classes"
• Copy Feature Classes to Geodatabase → (Rectangle) "Loop through feature classes and copy to Mod5A_SKulik.gdb"
• Verify 'cities' Feature Class Exists → (Rectangle) "Use ListFeatureClasses() to check if 'cities' exists"
• Print Debugging Info → (Parallelogram) "Print message confirming 'cities' layer existence"
• Use Search Cursor → (Rectangle) "Extract city names and populations for 'County Seat'"
• Print Extracted Data → (Parallelogram) "Print city names and population values"
• Create Empty Dictionary → (Rectangle) "Initialize county_seats dictionary"
• Reinitialize Cursor → (Rectangle) "Ensure fresh cursor for storing data"
• Populate Dictionary → (Rectangle) "Store city names as keys and populations as values"
• Print Dictionary Contents → (Parallelogram) "Display county_seats dictionary output"
• End → (Oval) "Script Complete"

This week's lab focused on Python scripting in ArcGIS Pro, specifically working with Search Cursors to filter and extract data from attribute tables. We explored concepts like setting up the workspace environment, enabling overwrite outputs, formatting SQL queries correctly, and structuring dictionaries to store extracted values.

One key takeaway was the importance of properly managing cursors. Since Search Cursors cannot be reused after iteration, reinitializing them when needed was crucial for ensuring data retrieval worked correctly. Additionally, using AddFieldDelimiters() helped avoid syntax errors when filtering the "County Seat" feature.

Another important lesson was verifying data before running operations. Listing feature classes in a geodatabase confirmed whether the "cities" layer was available, preventing errors before executing queries.

Some notes from this lab include:

• Workspace paths must be correctly set to access feature classes.
• SQL syntax in ArcPy requires special attention to quotation marks.
• Search Cursors do not refresh automatically—reinitialize them if needed.
• Debugging step-by-step helps identify where errors originate.
• Printing intermediate results can confirm that data is being processed correctly.

Overall, this lab reinforced the importance of structured scripting, careful SQL formatting, and proper cursor management in ArcGIS Pro. These skills will be valuable in future GIS programming tasks.