A set of software tools for processing DEMs (digital elevation models). Uses GDAL api, includes:
1) DEM Downloader,
where user specifies horizontal position and radius, and required DEM resolutions. Metadata are then retrieved using USGS-documented web API, processed, and finally DEMs are downloaded from remote server, with degenerate tiles further processed and/or merged.
2) DEM Processor,
which transforms from one datum (horizontal and/or vertical) to another, and/or from one projection to another, and then re-samples and/or re-tiles the resulting DEM rasters.
3) DEM Post-processor,
which runs on-line with navigation solution. It selects, from DEM Processor mosaic, those tiles that cover the area-of-interest, and forms a new mosaic. See RAM Wrapper Extension for further details.
4) DEM Validator,
which quantifies relative DEM errors (incl. non-topographic variability) and detects numerical artefacts in DEMs. It includes computation of histograms, information entropy, detection of boundary discontinuities via gradient approximation, detection of structure / periodicities / noise with 2D DFT (detrending, FFT, radial averaging of PSD, identification of spectral peaks).
