At the University of Hawai‘i Campus Arboretum, with use open source and free software for both practical and philosophical reasons. A combination of tools lets us create a variety of custom maps for public use (e.g. http://manoa.hawaii.edu/landscaping/plantmap.php ) and for our own management needs.

We make these maps more legible by showing the canopy area of the trees, color-coded by type, as well as points for the 6000+ trees on the map. (Searches retain the entire canopy but only the dots for the selected plants.) In order to create the canopy shapes, polygons were digitized from aerial photos, using either QGIS or GoogleEarth. We used QGIS to create the points (as centroids of the polygons), or to create polygons from point locations by buffering.

Once we have trees mapped, we join their locations to attribute data, and map them online using Google Fusion Tables, which enables us to merge that map with a table of species information that we can update independently. Using the Fusion Tables Wizard and some basic copy-and-paste html code, students created the custom map interface which allows users to search for plants by taxonomic, biogeographic, or use criteria.

Being able to set up our maps with free software has meant that we can extend or export this to other campuses or groups that might not have any budget for software or licensing. (We'll probably do some training workshops on this later in the year.) And we found that while there is an initial bump in the learning curve in setting this up, we've ended up with more control than we would have in an out-of-the-box mapping solution.

We continue to experiment with map design, adding features and integrating information, so I'm looking forward to seeing what other solutions people have found, and ways that we might think about making tree maps work together.

David Strauch
Curator, Campus Arboretum