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Help Articles are product support tips and information straight from the NV5 Geospatial Technical Support team developed to help you use our products to their fullest potential.



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How does the DEM Extraction module calculate post spacing?

If I have a QuickBird image at 4m spatial resolution and compute a level 6 DEM, what would the "post spacing" be relative to the resolution?

Post spacing (the DEM posts obtained during the matching process) may be estimated based on the following formula:

post_spacing = 2^(N-L) * GS * RF

where:
N is the highest terrain detail level
L is the terrain detail level that user selects
GS is the input stereopair image resolution
RF is the epipolar reduction factor

So if level 6 is the highest terrain detail available and you set the epipolar reduction factor to 1, then post spacing will be 4m, regardless of the output DEM pixel size.


Review on 12/31/2013 MM

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