Resource Mapping

Wednesday, March 28, 2007

GIS 2007 Assignment 4


Maps are visualizations of knowledge of a certain space. They can either be used for orientation (geographical maps) or for illustrating local information [1].
Most printed maps are geographic maps and used for orientaion. They are widespread and part of everybody’s daily life. Maptrix was designed for schools to teach the general use of maps and the information extraction out of geographical maps. It is available in hard copy and as a computer program [3]. The SANBI Biodiversity GIS is a free online programme that provides access to biodiversity information of South Africa in order to be used for conservation and land use planning [4].

The maps are made for different purposes and presented through a different medium. So, they differ in layout, information provided and application.
Paper is the medium used for most geographic maps. Geographic maps are two-dimensional projections of landscape and infrastructure. They are available in different scales and for nearly every place on earth [2]. Because only a limited area can be shown, several maps are often collected in atlases. The use of scales at a certain ratio (e.g. 1: 25,000) allows the calculation of distances whereas information about longitude and latitude together with a reticule gives information about the position [1]. The advantage of paper maps is their independence of any technical equipment.
The electronic version of Maptrix works with the type of geographic maps described above but presented on a computer. There are 52 5’x 5’ map extractions of 1’x1’ boundary boxes of certain places in South Africa available using a scale of 1:50,000. The extractions were carefully chosen to fit one of the four topics, rural settlement, urban settlement, transport and landscape. The maps are visible in a window smaller than the whole map and a mouse is required to move to the place of interest on the map [3].
Today, seamless electronic maps with a limited zoom function are available. With a printout of these maps the advantages of conventional printed maps can be combined with the choice of the center and zoom.
The Web Map Service SANBI Biodiversity GIS is a freely online available map service for South Africa. Sixty-four maps that show different aspects of biodiversity can be loaded up. Among them are maps that illustrate protected areas, habitat information, ecosystem status and future plans for protection, sometimes specified on certain areas. Additional information can be added in the form of different layers such as the information provided from a conventional geographic map (“base layers”) and the information from all the other provided maps. Beside the different layers, users can also add personal information for example: landmarks, polygons, lines and names. Other advantages are the provided zoom function and the seamless projection. All these different possiblities of adding and removing information makes the SANBI Biodiversity GIS a customizable web map service that can be used to show all relevant information for someone’s purpose. A GIS is not only used to create customized images. Information extraction is another big issue, for example measurement of distances and calculation areas to mention only two of them. Because of the many different available functions, a tutorial for the program is offered on the homepage [4].

GIS programs can provide the most recent information because it can be easily updated in parts (e.g. different layers). Printed maps and electronic maps often do not contain the most recent information. Electronic maps can be updated from time to time whereas printed maps can’t be changed once printed and published.

The information in the form of different features in printed maps and electronic maps is all summarized in a legend. Information beyond the identity of the different features is only seldom available. A GIS like the SANBI Biodiversity GIS offers in addition metadata, downloads, information about the projects shown in the maps, and contact data for more biodiversity information for certain areas. This is necessary to understand and to use the illustrated data.

Maps are a two-dimensional projection of our three-dimensional world and therefore either an equal area, an equal distance or an equal angle illustration [1]. Distortion in one of these geometrical features can’t be avoided. Beside these general map limitations, each of the different types of maps has some specific limitations.
Printed maps and elctronic maps like Maptrix have a fixed zoom level and can contain more or less details than required or show a to big or rather small area. They are not seamless and the area of interest is often not central. Customizable functions such as the use of different layers or addition of data don’t exist. Although the calculation of distances and areas is possible it is often complicated and not more than a rough estimation.
Electronic maps and the GIS require a computer or similar technological equipment, which is not accessible everywhere and to everybody. Some of the electronic programs are in addition very expensive. The GIS programs especially are often difficult to use and the preparation of data is still very complex so they are not yet commonly used. The SANBI Biodiversity GIS is an exception in view of its free accessibility and the tutorial that makes its use easier.

The computer-based technologies will replace the printed maps more and more especially if the prices decrease in the next few years. Navigation is already dominated by electronic technologies such as the navigation systems in cars. Although there is a constant trend towards digitalization, printouts will never become obsolete. The required technology might not always be available and a peace of paper is often still lighter than the navigation systems produced at the moment.
The GIS programs are less important for personal use than for bigger organizations, e.g. industry, universities or politics. These services for data processing and visualizations will grow in the next few years. Today the most GIS are still specified on certain topics like the SANBI Biodiversity GIS. Some topic spanning services will perhaps soon be provided.

*Geographic Information System


[1] Internet source: Accessed on 18 March 07

[2] Internet source: Accessed on 18 March 07

[3] Maptrix:
Electronic version

[4] SANBI Biodiversity GIS: Accessed on 18 March 07


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