Education had a light-hearted sidekick when the City’s corporate geo-informatics (CGIS) directorate hosted the annual GIS Day at the Metro Centre in Braamfontein.
CGIS used the global event, on 17 November, as an exciting way of teaching the public about what it does and how it does it. CGIS staff and their offices were dressed up according to the theme, which was “Four seasons … all year round”. Each season represented a specific area of expertise within the department.
Using GIS
GIS (geographic information systems) is a computer technology that combines geographic data such as the locations of natural and man-made features on the Earth’s surface, with other data like values and classifications, to analyse, manipulate and present maps and reports.
CGIS uses this technology to specialise in data capturing and maintenance, mapping, property information, database development and administration and internet map site development, which deals with updating the maps people have access to on the website.
This, to the uninitiated, is meaningless jargon, which is the primary reason behind GIS Day. The use of themes also enables visitors to associate fun with a technical field, and this year’s seasons invited people in with a melody of colour.
Walking through the doors meant jumping into autumn, where the information counter took pride of place. Exuberant staff in luminescent green and purple “GIS navigator” T-shirts beckoned through to a playground of reds and yellows and explained how enquiries were dealt with. The information counter deals with the administrative side of the directorate, and provides property information to individuals.
Autumn quickly turned into a winter wonderland, with the projects section coming into focus. Its most prominent function is the use of different maps to display information to clients. It uses cadastral maps, which illustrate boundaries and ownership of land, in addition to other maps, and also implements aerial photographs for each of the seven regions of Johannesburg. It is also possible to buy a CD of the regional maps for R350, which works hand-in-hand with the eServices website.
Mapping
Spring blossomed with data administration and mapping taking centre stage. This section uses ARC and IMS software, with information coming from the Deeds Office.
Sihle Zulu, a GIS specialist, explained: “We capture the data with co-ordinates because it is precise, and then turn them into maps and diagrams.” These are then used for property descriptions such as stand numbers. This department is also responsible for the Land Information System database, which was introduced two years ago.
Next, summer made its joyful appearance, where maintenance and aerial photography were explained and illustrated. Maintenance of the CGIS databases and the web applications that the specialists use is carried out here.
Senior GIS specialist Deena Naidoo explained the aerial photography feature. “The aerial photographs are only taken every three years because of the cost, but every time we improve on each data set,” she said. For instance, the 2006 photographs were 20cm pixel resolution, while the 2009 images were 15cm pixel resolution.
This resource can be used in a number of ways, such as viewing locations from different angles, and is particularly useful to property valuers who can use the functions in their line of business.
GIS Day was well-attended and after a whirlwind tour through the four seasons, it was evident that visitors were carrying away with them more than the free goodies they had received, which included a cold drink, a sweet, a pen and a Space Brief CD. Every year, CGIS hosts GIS Day events to showcase what it does, and to encourage people to take an interest in the uses of GIS technology.
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Autor(en)/Author(s): Lynley Main
Quelle/Source: Joburg, 18.11.2010
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