Talk:Digital elevation model
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For a draft of the article, see #Article draft.
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From Liu & Mason 2010 [1] DGM's are a subgroup of Surface models (should there be an own category?) and can be obtained by
Related articles already existing in this wiki are:
Article draft
- DEM stands for Digital elevation model. It can be represented as a regular grid of points or as a Triangular irregular network of points. DEMs are the basis for digitally produced relief maps.
Digital elevation models are sets of data representing the estimated height of a surface above a certain level, i.e. a Geodetic datum. It may represent the elevation of the bare earth, or include objects as buildings or tree canopies [1].
Types of DEMs
There are no official Definitions of different subgroups of digital elevation models, but the probably most used terms are Digital surface model (DSM) and Digital terrain model (DTM); the first model may quantify the height of the earth including objects on it's surface, while the latter models the elevation of the mere ground. Still, sometimes both terms are used to describe bare-earth models, leaving the original Digital elevation model term for models including objects above ground level[1].
Creation of DEMs
Photogrammetry
- Main article Photogrammetry
Digital elevation models may be obtained by aerial photography and spaceborne instruments such as ASTER, IKONOS or SPOT. The basic principle of photogrammetry is the retrieval of photographs from at least two different positions, which makes the measurement of object heights possible.
Laser Altimetry
- Main article Laser altimetry
SAR interferometry
- Main article SAR interferometry
DEMs in forestry
Related articles
References
- ↑ 1.0 1.1 1.2 Liu, J. G. & Mason, P. Essential Image Processing and GIS for Remote Sensing. (John Wiley & Sons, 2010).
