🎯 Learning Objectives
- Georeference a scanned paper map or aerial image to align it with the real world.
- Create empty Vector Datasets (Shapefiles/Feature Classes) with specific attribute fields.
- Digitize points, lines, and polygons by tracing features.
- Understand Snapping to ensure topological connectivity.
📂 Scenario: The Historic Campus
The University Archives has provided a scanned map of the campus from 1950. It is just a JPEG image with no coordinates. Your task is to align it to the modern satellite basemap and digitize the footprints of the original buildings to calculate how much the campus has expanded.
lab03_digitizing.zip
Contains: campus_1950.jpg (Unreferenced Image)
🛠️ Step-by-Step Instructions
Select your preferred GIS platform to view instructions:
Georeferencing
1. Add campus_1950.jpg to the map. It will ask to "Build Pyramids" (Yes).
2. Go to Imagery tab > Georeference.
3. Use the "Fit to Display" tool to bring the image roughly into view.
4. Add Control Points: Click a building corner on the JPEG, then click the same building corner on the Basemap.
5. Add at least 4 points. Click Save to burn in the coordinates.
Create Feature Class
1. In the Catalog Pane, right-click your Geodatabase > New > Feature Class.
2. Name: Historic_Buildings. Type: Polygon.
3. Add a Text field called Building_Name.
4. Click Finish.
Digitizing & Snapping
1. Go to Edit tab > Create.
2. Enable Snapping (the magnet icon).
3. Select the "Polygon" construction tool.
4. Trace the buildings from the 1950 map. Double-click to finish a shape.
5. Open the Attribute Table and type the names.
✅ Submission & Assessment
To complete this lab, you must submit:
- Screenshot 1: Your Georeferenced 1950 map overlaid on the modern basemap (set transparency to 50% to show alignment).
- Screenshot 2: Your digitized polygons with a label showing the "Building_Name".
- Bonus: Calculate the area of the "Old Main" building in square feet.