Aim of module

Merging multi raster files with different resolutions and accuracies into one continuous file.

General description

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

See also: Module GridMerge

Parameter description

-inFileinput grid files

Type: opals::Vector<opals::Path>
Remarks: mandatory
TO COME

-outFilemerged output file

Type: opals::Path
Remarks: mandatory
Path of output grid file in GDAL supported format.
Estimation rule: The current directory and the name (body) of the input file are used as file name basis.

-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...).

-gridSizegrid width x/y

Type: opals::Vector<double>
Remarks: mandatory
Size of output grid cell in x- and y-direction. Estimation rule: output grid size = grid size of 1st inFile

-sigmaApriorisigma of input grids

Type: opals::Vector<double>
Remarks: optional
Sigma values can be optionally defined for appropriate weighting input data sets based on their accuracy. The number of specific values have to match the number of input data sets. Nevertheless, it is also possible to force equal weighting by specifying a single value. If no sigma values are provided, the module uses 'natural' priority weighting, where the remainder to 1 of current weight is used as factor for all subsequent data sets.

-mergeWidthmerge width

Type: double
Remarks: optional
This value in coordinate units defines the width of the merge band in which the input raster are merged/blended into the continuous output grid raster. Make sure that value covers serval pixels of input raster with the largest grid cell.Note: If this value is omitted or less equal 0, only necessary distance transform raster are computed and the actual merging stage is skipped.

-mergeFuncmerge formula

Type: opals::String
Remarks: default=SIGW:8
An algebraic formula in generic filter syntax for converting a (normalised) distance into a merging/blending weight (has to be 0 at x=0 and 1 at x=1). The provided distance x is normalised by the merge width. Beside arbitrary user defined function, the module supports two predefined functions: LW....... linear weigthing (i.e., x))
SIGW:i... sigmoid weigthing with slant i ( i.e., 1/(1+exp(i*(-x+0.5)))

-nonOverlapMergeUse a non-overlap merge algortihm

Type: bool
Remarks: default=0
When activated, it is possible to vertical align non-overlapping dataset. More Details to come

-activateBorderMergeFlag for merging at grid borders

Type: bool
Remarks: default=0
If flag is activated the module also merges along the limit borders, in case the input files have the same limits. If the limits of the input files larger than the output limits plus the mergeWidth, the flag doesn't affect the final output raster.

-limit2D clipping window

Type: opals::MultiGridLimit
Remarks: optional
If -limit is skipped, the common area (intersection) of all input datasets is used.
MultiGridLimit: Defines xy-limits for output grid/raster datasets, either explicitly or depending on the limits of input datasets. The limit coordinates explicitly specified by left/lower/right/upper either refer to pixel centers (default) or corners, and may optionally get rounded to multiples of the grid size. 'intersect' and 'union' choose the intersection/union of limits of all inputs. dataset:i chooses the extents of the i'th dataset, with i in [0;nInputs).
Syntax: ['center'|'corner']['round']['intersect'|'union'|'dataset:'i|'('left lower right upper')']

-resamplinggrid resampling method.

Type: opals::ResamplingMethod
Remarks: default=bilinear

Possible values:  
  weightedAverage .... weighted average (low pass filter)
  simpleAverage ...... simple average (low pass filter)
  nearestNeighbour ... nearest neighbour
  bilinear ........... bi-linear interpolation
  bicubic ............ bi-cubic interpolation
  never .............. indicator avoiding resampling

Method to be used for resampling the input grids to the specified grid structure of the output grid.

-byproductIGroup: Options for optional byproducts

These parameters are used for creating option output files for better analysing the merging process.

.processStructureoptional process structure shape file

Type: opals::Path
Remarks: optional
Creates a polygon shape file that represents the internal processing structure.

.weightingoptional weight file

Type: opals::Path
Remarks: optional
The weights of each input data is represented as band within this raster file. The grid size corresponds to the merged output file.

.deviationoptional deviation file

Type: opals::Path
Remarks: optional
The absolute maximum deviation and the deviation of each input file to the final output raster in the merge band region is written to this multiband file.

Short examples

Examples

Running the command

opalsGridMerge

prints the usage screen.

References

Author: jo

Date: 13.09.2022