Geographical Information Systems
What is GIS?
Geographical Information Systems (GIS) can be basically regarded as the high-tech equivalent of the map. It is a computer-based system for the storage, management and analysis of geographic information and associated data.
Perhaps its most important characteristic is that is allows a wide variety of data to be integrated and combined in a formal, logical manner on the basis of spatial relationships. There are four basic categories of geographic data (both two and three dimensional landscape representations) which create layers of information, which a GIS can integrate:
• Images (aerial photos, scanned maps, satellite imagery, screen captures etc.)
• Lines, points and areas (roads, lakes, county boundaries, topographic lines etc.)
• Elevations (terrain heights of study area)
• Spatial databases (census data, resource inventory data, spatial event data etc.)
The user can then map, explore, analyse and model this data in different ways through the integration, interrogation and manipulation of these different information layers. Therefore GIS provides the facility to extract different sets of data to produce a map or data table which exactly meets the needs of the user. This has advantages over the traditional manual maps which are static and cannot be updated, statistical techniques or tabular computer map databases, which at most are digital versions of paper maps and although are easier to edit, lack analytical and integrative functions.
Basically there are two different modes of true GIS: Raster and Vector.
• Raster systems – in which the world is divided into a 2D grid of cells, each receiving a value. Remote sensing data comes in this format, so the system is essential for processing satellite images. Although this system has limited functions, especially when it comes to relational database design as each spatial feature must be represented as a large number of cells rather than a single feature; it is simpler to write programs for custom and in-house GISs.
• Vector systems – in which the world is divided into 3D polygons. This system is generally a better platform for complex spatial and statistical analysis as each spatial feature is represented as a single feature and various relationships are easier to represent. Recent release software systems integrate both modelling capabilities.
GIS is the first analytical tool that allows us to directly implement the ecological view of events and to achieve a holistic information management capability. It therefore holds promise in the struggle to solve difficult biological and management problems.
(Adapted from the Conservation GIS Starter Kit from the Conservation GIS Consortium - http://www.conservationgis.com)
Conservation applications of GIS
Documentation of world’s biodiversity.
• Document species. Basic inventory GIS coupled with remote sensing data, allow a crude classification and a rapid overall view of a large area. This view can then be used to focus field efforts into those areas most threatened. The occurrence of wildlife species can be predicted on the basis of habitat, putative species lists for little-known areas to help guide field efforts can be drawn up or the alarm sounded if an endangered species might be likely to occur in a little-known area threatened with destruction.
• Basic maps of flora and fauna. Used simply as a map management tool, GIS can help to organise a large collection of spatially referenced paper data. As a next step, tabular data on each species characteristics, requirements and status can be collected into the database and linked with the GIS to digitised maps. The relational power of the GIS allows data to be specifically maintained about each species at each site, such as its population and protection status, in addition to separate tables giving the overall global characteristics of a species such as biomass and life history. Once these links are made, it is then possible to produce maps from queries.
• Rapid inventory methods. GIS can combine physical data (rainfall, soil, elevation) or use remote sensing data to plot out draft habitat maps that can be field edited and verified more rapidly than a ground mapping program starting from scratch.
Ecological fieldwork and research with integrated interdisciplinary approaches.
All the efforts detailed below will rely extensively upon the integrative and modelling abilities of GIS. The success of these efforts will depend mostly on the quality of the data obtained and the thoroughness of the database design.
• Habitat dependencies, effects of habitat loss, population fragmentation, interactions between species, habitats and humans. Such GIS research must be based on a thorough knowledge of the species life history and natural history to have any relevance.
• Explore the factors determining a species range. Maps of actual species occurrence overlaid with present and former extent of suitable habitat form the basis of such analysis. Maps of human history, human activity, agriculture, other species and physical environment factors are all useful.
Management
• Define the relative environmental sensitivity of areas. Various measures of rarity, threat and proximity can be combined in order to produce maps of environmental sensitivity.
• Determine which species and habitats are protected. Once species and habitat maps are combined with protected areas and human pressure maps, selection operations within the linked databases will reveal the percentage of range under threat for each species.
• Identify sites for protection. Modelling would be used as in the above examples to flexibly reflect the criteria for site protection.
• Manage the sites. A GIS used to manage baseline data can model different management scenarios to explore alternative strategies to help guide the search for ideal management strategies.
• To explore resource use by local communities. The ability of a GIS to combine data form different sources (vegetation to demographic maps) enables analysis of local economies in ecological or bioregional terms. Patterns of local livelihoods and their impact on local environment can be discerned and used as a guide in management plans.
Monitoring
Large complex spatial databases would be impossible without the database management tools of GIS. Most important of these is tiling, the ability to break up large databases into smaller manageable pieces linked together in a common spatial structure and a common database definition. GIS allows users to monitor the changes in many variables including diversity, deforestation, climate change, resource use, land-use and pollution over large areas, and collate information on current status and trends to support policy.
Application and Advocacy
For environmental information to be useful and effective among decision makers, it needs to be obtained in a form that can be easily integrated with the rest of their activities. The dual ability of a GIS to produce information in a map form or linked tabular form gives flexibility. Maps are among the most useful of formats for information since they represent spatial patterns directly and unambiguously. In this sense GIS has greatly simplified the preparation of integrated biodiversity conservation strategies with local, national and international bodies.
Points to consider in using GIS for conservation
1) Database design and analysis. Specialist consultants and analysts are often needed to carry this out. This of course depends on the complexity of GIS required, but GIS cannot reach its fullest potential for integration, data sharing and analysis without a solid design. This can be costly but there are many non-profit consultants, resources or training courses available to make GIS a feasible option. Consultants teaching users how to solve their own GIS problems rather than trying to build databases or conduct analysis for them is fundamental to the philosophy of a successful and self-sustaining GIS.
2) Time-frame. Adoption of a GIS takes a minimum of six months if you are familiar with computers, database management programs and paper maps, otherwise a year is reasonable. This is based of one person working full-time in remote circumstances with limited help. This time can be shortened with training or one-site help.
3) Hardware. For a functioning GIS the following are required: as much computer power and memory that can be afforded or accessed, colour printer, high resolution scanner or digitising scanner, optional GPS unit. It is usually possible to meet all hardware needs through donations. However, this is time-consuming to organise, can take up to nine months to wait for delivery and depends on the country focus of the donation programs.
4) Software.
• ArcInfo software ($3,500), developed by ESRI (Environmental Systems Research Institute, http://www.esri.com) is the most widely used and requested GIS software among conservation and planning groups. Although it is often criticised for being too complex due to its 3,000 commands and great flexibility, it can be used to enter, edit and output maps with only 20 basic commands. It also has the ability to keep up with the most complex and demanding tasks an advanced user might require. A modern PC is required for running this software.
• Arc/View software ($1,500) requires no formal training requirement and allows a separate community of data users to exist. It is completely graphic in operation and easy to use with no typed commands. Novices can make maps in one hour. Indris software is similar in specifications (. This software can be run from a laptop.
• The Internet offers many free tools and resources for making maps, by collating GIS data and using GPS data. Many are free and fully functional, while some may be trial versions or offer additional features after payment of a registration fee.
• There are ten basic features to look in GIS software. Does the software:
1. Offer spatial data analysis and connect to external databases?
2. Utilise digital aerial photographs and other imagery?
3. Import a wide range of vector data and export products for use in other GIS programs?
4. Remove distortions from scanned photos or maps and geo-reference the images?
5. Mix images and vector drawings that originate in a variety of projections and coordinate systems?
6. Feature easy-to-use drawing tools for building maps?
7. Integrate the Global Positioning System (GPS)?
8. Visualise 3D terrains and surfaces?
9. Provide quality graphics for printed maps and reports or digital media?
10. Have good organisation and clear, simple instructions?
5) Difficulties in getting a GIS into remote and developing country environment. Three main difficulties are faced: local politics, getting the required hardware and devices to work together and getting dedicated GIS staff and computer programmers so field staff can remain in the field.
6) Constraints of representational transformations. Modelling within GIS involves ‘forcing’ ecological data into arbitrary spaces whose boundaries do not necessarily coincide with real boundaries. Species are unlikely to perceive these boundaries and they may not represent the functioning ecosystem.
7) Data collection in the field. All data must be coded by geographical location so a reliable base map or geo-referenced image is required. Two methods are available: 1) Features marked and a corresponding GPS location obtained using a transparent grid overlay. This is more time consuming as data should be edited before importing them manually into a GIS, or 2) Field data collected with a PDA, laptop or tablet PC with the appropriate GIS software (ArcPad).
8) Reality. Potential costs and drawbacks of GIS must be carefully weighed, but in reality even small conservation groups can easily develop a GIS with minimal costs and greatly enhance their effectiveness. Before starting a GIS, public agencies and other conservation agencies should be contacted to see what has already been developed and what is available for adoption, to avoid duplication in effort.
Important websites
• GIS.com. This is an excellent portal to GIS information on the web and was created by ESRI a leading GIS software developer. Visit http://www.gis.com
• Excellent web-based tutorial for using INDRISI GIS software from the University of Salzberg. Visit http://www.sbg.ac.at/geo/idrisi/wwwtutor/tuthome.htm
• Biological conservation and GIS e-mail list run by the Conservation GIS Consortium. Visit http://pete.uri.edu/archives/consgis.html
• Book and web-based training resources. “Geographic Information Systems and Science” by P.A. Longley, 1999 and “Geographical Information Systems and Science” by P.A. Longley, 2001 (visit Wiley publishers at http://www.wiley.co.uk) and the Virtual Campus from ESRI (visit http://campus.esri.com). These three learning resources will provide an excellent package for your GIS needs.
• Clark Labs with United Nations Institute for Training and Research – Meeting the challenges for environmental decision making with GIS. An excellent online workshop for GIS training. Visit http://www.clarklabs.org
Background and further reading
Conservation Technology Support Program. GIS Planning Tutorial