2009-08-07
Southern Mapping Company partners with the Johannesburg City Council
More than 80 percent of the average local government’s work involves land or geographically related issues. The City of Johannesburg’s Corporate Geo-Informatics (CGIS) Directorate is responsible for providing accurate and relevant geographically referenced spatial and related information for commerce and industry. Geographic information and the associated management systems are an integral part of planning and implementing the City’s vision for infrastructure development and management.The CGIS is in the process of updating their aerial dataset. The company tasked in assisting with this process, Southern Mapping Company (SMC), is responsible for flying the entire City of Johannesburg as well as the Driefontein water treatment works. The company will provide the City Council with a new set of colour digital orthophotos, a Digital Elevation Model (DEM) dataset and contours of the city.
A Geographic Information System (GIS) is a computer technology that is used by local governments to combine geographic data (including both natural and man-made features of a specific surface area) and other information such as street names, zoning, property values and demographics to generate visual maps and reports.
Peter Moir, chief executive of Southern Mapping Company: “Every three years the City council is required to update their aerial datasets. The company had to ensure that we would be able to provide accurate orthophotos within strict timelines. The datasets are critical for planning purposes. They facilitate the CGIS in the analysis of special trends and offers up to date information on new developments on the ground. The new aerial photographs are compared with old photographs in order to investigate where changes have taken place, for example, where informal settlements have developed and the impact this change will have on the city and future infrastructure planning.”
The company utilises Lidar (light detection and ranging laser) technology to survey allocated areas. 2006 was the first year that the CGIS used the Lidar technology. This advanced technology uses laser distance measuring to perform topographic mapping. When combined with a digital camera, a complete high speed mapping system is created.
Peter Moir says: “There are various processes involved when gathering the necessary data. We have to obtain CAMU flight clearance before we start. We then fly over the allocated area, in this case an area of 1938km² needed to be surveyed. The data obtained from the Lidar and digital camera is downloaded and processing begins. Raw images are developed into standard jpg images and orthophotos are then created. The resolution of the pictures ranges from 25cm to 20cm for existing images and will be improved to 15cm this year. This cuts out field work, saving time and resources. The last step in the process is for us to construct a survey report which details all the technical data pertinent to the project.”
The orthophotos and surveys have also proven to be beneficial to the Johannesburg Roads Agency to assess flooding areas, gravel road upgrading, road markings, new route developments and road alignment improvements. It is also being extensively used by Johannesburg Transport for the Bus Rapid Transport project as well as by the Johannesburg Development Agency in the upgrading of the City. The accurate 25cm contours are used in stormwater design and the clear, accurate orthophotos are used to maintain and manage the cities assets.
Probably the biggest advantage GIS and aerial surveying offer to any discipline is to portray vast amounts of complex information through simple visual maps or graphs. For the user, the information is immediately understandable and can be translated into taking the right action or precaution.
Peter Moir says: “We are pleased to have assisted the City Council on this project. The new aerial photographs will add value to the CGIS database. By using the latest available imagery to assist in future planning of the City, it supports the City of Johannesburg’s vision to become a world-class city for 2010 and beyond.”
Southern Mapping Company
SMC provides topographic surveys and mapping for a variety of industries and sectors. These include civil engineering and infrastructure development, mineral explorations and mine management, environmental planning and rehabilitation, and urban and agricultural planning. The company operates worldwide, but specialises throughout Africa. SMC one of the first in Africa to combine Lidar and hyperspectral imaging technology. For more information about Southern Mapping Company please visit http://www.southernmapping.com.Date issued: June 2009
Issued by: Martin Snoek Communications (MSC)
Contact person: Lisa Andersen
E-mail: lisa@martinsnoekcommunications.com
Telephone: (011) 4657652 / (011) 4657652
Fax: 0866841769 Address: P O Box 954, Fourways, 2055
