set the scale values for a VRT_x object

Set the Scale XML tag for a VRT_x object. This information is preserved in derived VRT and GeoTIFF files.

Usage

vrt_set_scale(x, scale_value, band_idx)

Arguments

x

A VRT_x object

scale_value

a numeric vector of length 1 or equal to the number of bands in the VRT_x object.

band_idx

numeric; the target band position(s) to set the scale value for. If NULL, The scale_value will be set for all bands.

Examples

s2files <- fs::dir_ls(system.file("s2-data", package = "vrtility"))
ex_collect <- vrt_collect(s2files)
ex_sc1 <- vrt_set_scale(
  ex_collect,
  scale_value = 1e-4
)
print(ex_sc1[[1]][[1]], xml = TRUE)
#> → <VRT Block>
#> VRT XML: 
#> 
#> <?xml version="1.0" encoding="UTF-8"?>
#> <VRTDataset rasterXSize="354" rasterYSize="334">
#>   <SRS dataAxisToSRSAxisMapping="1,2">PROJCS["unknown",GEOGCS["unknown",DATUM["Unknown based on WGS 84 ellipsoid",SPHEROID["WGS 84",6378137,298.257223563,AUTHORITY["EPSG","7030"]]],PRIMEM["Greenwich",0],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]]],PROJECTION["Lambert_Azimuthal_Equal_Area"],PARAMETER["latitude_of_center",50.72],PARAMETER["longitude_of_center",-3.51],PARAMETER["false_easting",0],PARAMETER["false_northing",0],UNIT["metre",1],AXIS["Easting",EAST],AXIS["Northing",NORTH]]</SRS>
#>   <GeoTransform> -3.5400000000000000e+03,  2.0000000000000000e+01,  0.0000000000000000e+00,  3.3400000000000000e+03,  0.0000000000000000e+00, -2.0000000000000000e+01</GeoTransform>
#>   <VRTRasterBand dataType="UInt16" band="1">
#>     <NoDataValue>0</NoDataValue>
#>     <ColorInterp>Gray</ColorInterp>
#>     <ComplexSource>
#>       <SourceFilename relativeToVRT="0">/home/runner/work/_temp/Library/vrtility/s2-data/exe_2024-06-02_12-21-19.tif</SourceFilename>
#>       <SourceBand>1</SourceBand>
#>       <SourceProperties RasterXSize="354" RasterYSize="334" DataType="UInt16" BlockXSize="256" BlockYSize="256"/>
#>       <SrcRect xOff="0" yOff="0" xSize="354" ySize="334"/>
#>       <DstRect xOff="0" yOff="0" xSize="354" ySize="334"/>
#>       <NODATA>0</NODATA>
#>     </ComplexSource>
#>     <Description>B02</Description>
#>     <Scale>0.0001</Scale>
#>   </VRTRasterBand>
#>   <VRTRasterBand dataType="UInt16" band="2">
#>     <NoDataValue>0</NoDataValue>
#>     <ComplexSource>
#>       <SourceFilename relativeToVRT="0">/home/runner/work/_temp/Library/vrtility/s2-data/exe_2024-06-02_12-21-19.tif</SourceFilename>
#>       <SourceBand>2</SourceBand>
#>       <SourceProperties RasterXSize="354" RasterYSize="334" DataType="UInt16" BlockXSize="256" BlockYSize="256"/>
#>       <SrcRect xOff="0" yOff="0" xSize="354" ySize="334"/>
#>       <DstRect xOff="0" yOff="0" xSize="354" ySize="334"/>
#>       <NODATA>0</NODATA>
#>     </ComplexSource>
#>     <Description>B03</Description>
#>     <Scale>0.0001</Scale>
#>   </VRTRasterBand>
#>   <VRTRasterBand dataType="UInt16" band="3">
#>     <NoDataValue>0</NoDataValue>
#>     <ComplexSource>
#>       <SourceFilename relativeToVRT="0">/home/runner/work/_temp/Library/vrtility/s2-data/exe_2024-06-02_12-21-19.tif</SourceFilename>
#>       <SourceBand>3</SourceBand>
#>       <SourceProperties RasterXSize="354" RasterYSize="334" DataType="UInt16" BlockXSize="256" BlockYSize="256"/>
#>       <SrcRect xOff="0" yOff="0" xSize="354" ySize="334"/>
#>       <DstRect xOff="0" yOff="0" xSize="354" ySize="334"/>
#>       <NODATA>0</NODATA>
#>     </ComplexSource>
#>     <Description>B04</Description>
#>     <Scale>0.0001</Scale>
#>   </VRTRasterBand>
#>   <VRTRasterBand dataType="UInt16" band="4">
#>     <NoDataValue>0</NoDataValue>
#>     <ComplexSource>
#>       <SourceFilename relativeToVRT="0">/home/runner/work/_temp/Library/vrtility/s2-data/exe_2024-06-02_12-21-19.tif</SourceFilename>
#>       <SourceBand>4</SourceBand>
#>       <SourceProperties RasterXSize="354" RasterYSize="334" DataType="UInt16" BlockXSize="256" BlockYSize="256"/>
#>       <SrcRect xOff="0" yOff="0" xSize="354" ySize="334"/>
#>       <DstRect xOff="0" yOff="0" xSize="354" ySize="334"/>
#>       <NODATA>0</NODATA>
#>     </ComplexSource>
#>     <Description>SCL</Description>
#>     <Scale>0.0001</Scale>
#>   </VRTRasterBand>
#>   <Metadata>
#>     <MDI key="datetime"/>
#>   </Metadata>
#> </VRTDataset>
#> 
#> 
#> 
#>  VRT SRS: 
#> PROJCS["unknown",GEOGCS["unknown",DATUM["Unknown based on WGS 84 ellipsoid",SPHEROID["WGS 84",6378137,298.257223563,AUTHORITY["EPSG","7030"]]],PRIMEM["Greenwich",0],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]]],PROJECTION["Lambert_Azimuthal_Equal_Area"],PARAMETER["latitude_of_center",50.72],PARAMETER["longitude_of_center",-3.51],PARAMETER["false_easting",0],PARAMETER["false_northing",0],UNIT["metre",1],AXIS["Easting",EAST],AXIS["Northing",NORTH]]
#> 
#> 
#> Bounding Box: -3540 -3340 3540 3340
#> Pixel res: 20, 20
#> Assets: B02, B03, B04, SCL
#> No Data Value(s): 0, 0, 0, 0
#> Date Time: NA