Calmap is web-mapping application that we developed for the CERES group at the Resources Agency of the State of California. Calmap was developed as a support application for the State's Prop40 and Prop50 grant program for water conservation and development--project applicants document their projects via a web application of which Calmap is part of. Specifically, Calmap lets users define their project boundaries; users can select from pre-existing data (e.g., county boundaries, Calwater watershed boundaries), edit these and digitize new boundaries. In support of these functions, Calmap provides users with smooth panning and zooming controls and layer selection tools to select from a number of backdrop map sources including USGS maps, air photos, satellite images and locally stored vector data; and Calmap provides users with a simple set of editing tools to create and delete points, lines and polygons.

Calmap is designed to be simple to maintain. Calmap lives on Linux servers. Calmap uses entirely open-source web technology; it is a Javascript/perl application utilizing University of Minnesota Mapserver and Postgres/PostGIS and other OpenGIS technologies. There's only a small amount of locally stored backdrop data (limited to a few boundary and place name shapefiles) and most data (DRG map images, satellite imagery, air photos) is obtained in real time from other servers via the OpenGIS WMS protocol. Edit data--data utilized in the boundary creation--is stored in a PostGIS database. Data management is entirely accomplished with SQL. We find that PostGIS offers a rich collection of spatial functions with great potential to support future web GIS applications.

Calmap is also easy on the user. It is a pure DHTML (Javascript) application; users do not need to install plugins or other software--any contemporary Web browser will do.

Calmap is customizable and extensible. We have developed supporting gazetteer and text search tools. Being open source and part of the Mapserver community, Calmap is easily adapted to take advantage of the ever-expanding set of spatial applications developed by this community.

Contacts

Geographic Information Science Center, UCB (GISC)
Project manager: Howard Foster Ph.D. (hfoster@gisc.berkeley.edu)
Programmer: Eric Zhang (eric@gisc.berkeley.edu)

Screenshot

Editing features with the Calmap application...

Sample zoomed view of northern California.