The dataset may be used for the following applications:
A DSM is a raster elevation model of the first surface terrain features such as buildings, vegetation and other cultural features. It provides a spatially referenced layer over which other data layers can be draped. The accuracy values provided are for measurements made in unobstructed areas with slopes less than 10°. Accuracy will degrade on slopes greater than 10°.
A Tropical DTM is a pseudo bare earth raster elevation model that has had some of the vegetation, buildings and other cultural features digitally removed. The Tropical DTM has been derived from the Digital Surface Model. The accuracy values provided are for measurements made in open, unobstructed areas with slopes less than 10°. Accuracy will degrade on slopes greater than 10°.
The Tropical DTM will meet the following accuracies in clear open areas located in areas of slopes less than 10°:1.0 meter RMSE
When determining obstructed areas please take into consideration that the areas are adjacent to obstructions are also obstructed due to the viewing geometry (local incidence angles 30° to 60°). A DTM generated from the DSM in obstructed areas is completely dependent on operator’s ability to estimate where the terrain is below the obstruction. Intermap does not provide an accuracy statement for DTM or contours generated in obstructed areas.
Intermap will edit the first surface elevation data to ground level to the best of our ability, but due to the lack of good ancillary data, larger areas of vegetation (greater than 100m across) may not achieve our target vertical accuracy for bare earth elevations.
Tropical DTM is not a standard or core product and is not detailed in the Product Handbook.
An ORI is a uniform and seamless grayscale image of the earth’s surface that is spatially referenced to the DSM and DTM products. It is similar to a black-and-white aerial photograph but provides a means of viewing the earth’s surface in a way that accentuates features differently than with aerial photography.
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