Contours

Contours are essential for many applications, including contruction planning, hydrological modelling and environmental management. Geosmart Space provides contour data with 50cm vertical invterval spacing for anywhere in South Africa. Other intervals (e.g. 1m, 2m, 5m) can also be provided. The contours can be converted to a range of formats, including those compatible with engineering software such as CAD and ModelBuilder. 

Below is an example of countours for a construction site. The high resolution aerial photography (or satellite imagery) shown in the background can also be provided (in most cases at no additional cost). 

 

Product Details:

Vertical interval 50cm, 1m, 2m, 3m, 5m 
Vertical accuracy 50cm
Horizontal accuracy 1m
Format Shape, Geodatabase, DXF, and many more
Price See pricelist below

 

IMPORTANT: The contours are derived from the DEMSA2, which is a digital surface model (DSM), not a digital terrain model (DTM). In other words the contours represet the bare earth elevation as well as the heights of objects (e.g. trees, buildings) on the earth's surface. See the conceptual difference between a DSM and a DTM in this image:

 

It is possible to convert the DEMSA2 to a DTM and then extract contours from the resulting DTM. Using a process called DSM2DTM conversion one can infer the heights of the bare earth. We call the resulting DTM the DEMSA2_t product. However, it should be noted that DSM2DTM conversion is never perfect and we cannot guarentee quality conversions. In some areas (e.g. forested landscapes) it is impossible to infer the bare earth terrain (because the bare earth is not visible), which causes gross errors and artefacts.

 

Pricelist

Order size Price
< 100 km2 R7500 *
100 - 300 km2 R15 000 *
> 300km2, per square km R50.00 / km2 *+
Per 1:50 000 map sheet (e.g. 3318dd) R25,000.00 / sheet +
Per quarter degree square (e.g. 3318d) R75,000.00 / square +
National R5,000,000.00

* Areas of interest must be rectangular, with a minimum width of 1km.

+Substantial discounts (up to 50%) are offered on large orders. Please enquire.

DSM2DTM conversion is available on request. DEMSA2_t (see above) prices vary between 150% and 200% of the listed prices.

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