Module DtmAccuracy

Table of Contents

• Aim of module
• General description
• Parameter description
• Examples
• References

See also

opals::IDtmAccuracy

Aim of module

Derives a spatially variable DTM accuracy measure based on the local point height accuracy, point density, and curvature.

General description

TODO: More details on opalsDtmAccuracy with much more words, possibly on several lines.

See also

Module DtmAccuracy

Parameter description

-inFileinput ODM file

Type: opals::Path
Remarks: mandatory
ODM FIle containing the data points/lines used for the DTM interpolation.

-gridFileDTM grid file

Type: opals::Path
Remarks: mandatory
DTM grid file in GDAL supported format for which the local accuarcy should be calculated.

-outFileoutput accuracy gridfile name

Type: opals::Path
Remarks: estimable
Path of output grid file receiving local accuracy file in GDAL supported format.
Estimation rule: The current path and name (body) of the input DTM file are used as file name basis. Additionally, "_acc" and the default extension of the output format are appended.

-oFormatgrid file format [GTiff,AAIGrid,USGSDEM,SCOP...]

Type: opals::String
Remarks: estimable
Use GDAL driver names like GTiff, AAIGrid, USGSDEM, SCOP... .
Estimation rule: The output format is estimated based on the extension of the output file (*.tif->GTiff, *.dem->USGSDEM, *.dtm->SCOP...).

-neighboursnr of nearest neighbours used for grid point interpolation

Type: int32
Remarks: default=8
Defines the number of neighbouring points around each grid point used for the estimation of the local grid point accuracy.

-searchRadiusmaximum search radius for point selection

Type: double
Remarks: estimable
Only points within the given search radius are considered for the accuracy estimation of a single grid post. If the search area contains too few points for successful accuracy estimation, the respective grid point is omitted (void).
Estimation rule: searchRadius = 3 * DTM grid size .

-selModedata selection mode

Type: opals::SelectionMode
Remarks: default=nearest

Possible values:  
  nearest .... pure nearest neighbour (nn) selection 
  quadrant ... quadrant-wise nn selection, ie. nn per quadrant, then 2nd nn per quadrant, ...
  octant ..... octant-wise nn selection, ie. nn per octant, then 2nd nn per octant, ...

Please note that quadrant wise data selection on the one hand reduces extrapolation effects, but on the other hand decreases the processing performance

-filtermodify the input using a (tree of) filter(s)

Type: opals::String
Remarks: optional
A filter string in EBNF syntax as described in section 'Filter syntax' can be passed to restrict the set of input points (e.g. to consider ground points only).

-noDatanodata value indicating void pixels

Type: double
Remarks: default=9999
Value representing an undefined accuracy value in the output grid model.

Examples

Running the command

opalsDtmAccuracy

prints the usage screen.

References

Author

gm

Date

18.3.2015