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National Geographic Information System |
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By: Mónica Ruano and Miriam Aguilera.
During recent years,
Guatemala has experienced an increased demand for reliable geographic and
cartographic information covering social, economic and natural features, among others, to
assist in the development of the country, especially in what concerns public investments.
For such reason, a
Commission to coordinate the Information System for Geographic Modernization (CCMSIG) was
created in 1996. This commission was a Presidential initiative to strengthen,
standardize and modernize the country’s geographic information. Conforming the
commission were a Presidential delegate, a representative from the National
Geographic Institute, one from the Secretariat of Planning and Programming for the
Presidency (SEGEPLAN), consultants from the United States Agency for International
Development (USAID), consultants from the World Bank, representatives from the Registry of
Property, the National Institute of Statistics (INE), and the Ministry of
Defense.
At the time, the
objectives of the commission were to promote institutional integration, to decide upon standards
for geographical information and to provide guidelines to develop the
national cadastre, in order to enable all the participating organizations to work
with the same standards, concepts and technical specifications.
In 1998, the first
results from international cooperation (Canada, Sweden, France and Japan) became evident
through the implementation of the several projects that intend to modernize the
National System of Geographical Information.
The next step, in
May of 1999, was the creation of the Interinstitutional Unit. The Unit began to
produce the National Geographic Database, UNISNIG, whose duties would
involve coordination, promotion and organization of the National Geographic
Information System. During 1999, the National Geographic Institute (IGN), worked
coordinated with the Secretariat of Planning and Programming for the Presidency
(SEGEPLAN), and other government agencies, a cartographic project of most importance: The SISTEMA
UNIFICADO DE INFORMACION NACIONAL "SUNIL" (National Unified
Information System).
The SUNIL project, a
cartographic and information experience, is the very first at a national level of
organization which enables access to completely digitized geographic
information in record time.
The Guatemalan
government and its agencies, as well as all international organizations, will be able to
access through Intranet. SUNIL is a unique reference for all projects, for the planning
and monitoring of several programs and is a valuable aid in the decision-making process
for public investments.
Scanning of the sources: upon getting the sources ready, the next step is scanning. Scanned sources were: roads, drainage, contour lines, and administrative division layers. As an additional reference information, the geographic coordinates of every topographic sheet were also included.
Cleaning of the raster images: scanning produces raster format images. The scanning process causes spots in the images. The spots are therefore erased using appropriate software.
Installing raster images in the computer: first, the images are installed in the workstation, taking as reference the four vertices in each image that contain the geographic coordinates. The software generates an automatic process which converts these coordinates into UTM (Universal Transverse Mercator), used for rectifying and georeferencing the image.
Digitalizing and Vectorizing: we used ARC INFO 7.1.2 for both processes. Some programming in AML was required to automate frequently used commands and tasks.
Attributes Setting: attributes were set depending on the nature of the layers. E.g., the roads network (rca) uses a classification (Central American, national or state), a condition (all-weather, hard surface, all-weather loose surface, dry loose surface, track) and the number of classification (CA-1,10).
Quality Control: after digitation and vectorization of each layer are completed, a partial print is produced to confront the digitized information against the sources of information. If any errors are found, they are corrected.
Joining adjacent sheets: next step after verifying the information of the 13 sheets, is to join adjacent sheets in order to obtain layers for the total Guatemalan territory.
Quality Control: the work would not be finished if the quality of the final information is not verified. First, the information per sheet was viewed in ARC VIEW 3.1, then it was printed and verified again against the information sources.
Database Integration: this is the last step of the technical process. All the digitalized information is integrated. The geographic information is ready to be used for developing applications or for a final print.
National Geographic Institute of Guatemala (IGN) http://www.ign.gob.gt
Secretariat of Planning and Programming for the Presidency (SEGEPLAN) http://www.segeplan.gob.gt
National Institute of Statistics (INE) http://www.ine.gob.gt
Del Valle University http://www.uvg.edu.gt
* Interinstitutional Unit
* United States Agency for International Development (US-AID)
* National Geographic Institute - France
International (IGN-FI)