Volume 1, Number 4—October 1995
News and Notes
Building a Geographic Information Systems (GIS) Public Health Infrastructure for Research and Control of Tropical Diseases
A course on the use of Atlas GIS and associated peripherals, such as digitizing tablets and global positioning systems (GPS), to build a GIS public health infrastructure in Latin American countries was taught August 7 to 18, 1995, at the Centers for Disease Control field station in Guatemala City, which includes the Medical Entomology Research Training Unit housed at the Universidad del Valle de Guatemala. The course was funded by the Special Programme on Research and Training in Tropical Diseases and presented by the Latin American Tropical Disease Research Training Consortium. Course instructors included statisticians and epidemiologists from the Division of Parasitic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention in Atlanta, Ga., USA, and in Guatemala City, Guatemala, and staff from the National Aeronautics and Space Administration, Center for Health Application of Aerospace Related Technologies, Ames Research Center, Sunnyvale, Calif., USA.
Objectives of the training included mastery of the principles and general concepts of all GIS systems; use of Atlas GIS/DOS to associate map files with databases to produce thematic maps, manipulate various layers (rivers, highways, village locations) of the map files to produce customized maps, create buffers around geographic features, and use them in simple analyses; designing georeferenced data files that can be read by the GIS; digitizing paper maps to acquire new data for building a GIS; use of GPS to obtain latitudes, longitudes, and elevations of villages and other major landmarks and use this information in the GIS; and mastery of importing/exporting databases and map files.
The course was designed to enable participants to set up and use a GIS for research, planning, or operational purposes. Participating were institutions from Mexico (two teams), Colombia (two), Puerto Rico, Costa Rica, Venezuela, Guatemala (two), Ecuador, and Brazil. Each team came to the course with ideas, maps, and data pertaining to an existing project that would be continued at their home institution. Student project areas included onchocerciasis, malaria, water sanitation, leishmaniasis, and public health and natural resource utilization/preservation. The students were taught digitizing and were asked to use Guinea worm surveillance data to create their own GIS.
A full day was devoted to geographic analyses. Topics covered included aggregating data from one geographic layer to another, combining geographic features with common database values, and combining selected features to form new map layers. A workshop on remote sensing, GIS, and image classification explained that satellite imagery and remotely sensed data are obtained by measuring reflectance on seven spectral frequencies and that ground cover can be partially deduced by the amount of reflectance at each band. Field exercises to practice GPS use in the Lake Atitlan area followed. Another workshop covered advanced digitizing and gave each team a good start on the digitizing part of their projects. Individual instructions were given on how to import map files from other GIS programs into Atlas GIS. Lastly, the Guatemalan onchocerciasis GIS system was presented as a case study.
In addition to the 2 weeks of training, each participating institution received a copy of all lecture notes, and the following software, complete with documentation: Atlas GIS/DOS, Import-Export, and Arcview 2 the critical hardware needed to continue the project at home. An onging Internet-based discussion group made up of class organizers and participants, as well as other interested parties, is being planned.