GEOG323-3 Exercise - Adding a New Georeferenced Image Basemap Layer

GEOG323-3 Exercise - Adding a New Georeferenced Image Basemap Layer

Synopsis: Students will modify, tile and uplaod a new base map for or

Possible Course: 323
or 328 ( or other advanced cartography or GIS course)

Learning Outcomes: (1) Students will become explore projection transformations and the tiling systems used by Google Maps API for large images. (2) They will contribute to a campus-wide
participatory planning process - asset mapping.

Background: Just about any georeferenced image can be used as as a base map for the UVic Community Green Map ( Currently, we have three options: Google's standard maps, a 2007 UVic Aerial Photo, or a UVic Thematic Map (2007).In this exercise, students will learn how to take a new Aerial Photo and tile it and then upload it to the web map server.

Suggested Readings

Suggested Instructions

We are going to use a Python script that calls GDAL (a translator library for raster geospatial data formats) and PROJ.4 (a cartographic projections library) within the FW Tools shell.

Step 1. Down load FW Tools from:

Step 2. Install and then double-click on the FWTools Shell link on your desktop.

Step 3. Download gdal2tiles python script python script
Right-click and save...

Step 4. From the FWTools shell, look at the gdal2tiles arguments...
> python c:/

Step 5. From the FWTools shell, run the gdal2tiles python script with you image file and output directory listed...
> python c:/ -title "UVic Aerial Photo 2008" -v D:/PROJECTS/UVicGreenMap/AerialPhotos/2008/Uvic2008.TIF D:/PROJECTS/UVicGreenMap/AerialPhotos/2008/tiles08

Step 6. Zip the tiles folder and move it to the server (you will need your TA's help here). The TA will unzip the folder into the correct place on the server (HERE).

Step 7. Login to or

Step 8. Go to and click on the Base Maps tab.

Step 9. Click add New Base Map [Tile Cache]

Step 10. Add the following (add your own values):

  • Name: My New Layer ("2000 Aerial Photo")
  • Display Name: "2008 Photo"
  • Path to tiles: "files/tiles_2008" (must match where teh TA has put your zipped files)
  • Max and Min Tile Zoom - experiment with these