pkextractimg - extract pixel values from raster image using a
raster sample
pkextractimg
-i input [-s sample] -o output
[options]
pkextractimg extracts pixel values from an input raster
dataset, based on the locations you provide via a sample file. The sample
should be a raster dataset with categorical (integer) values. The typical
use case is a land cover map that overlaps the input raster dataset. The
utility then extracts pixels from the input raster for the respective land
cover classes. To select a random subset of the sample raster dataset you
can set the threshold option -t with a percentage value. You can
provide a threshold value for each class (e.g. -t 80 -t
60). Use value 100 to select all pixels for selected class(es). As
output, a new copy of the vector file is created with an extra attribute for
the extracted pixel value. For each raster band in the input image, a
separate attribute is created. For instance, if the raster dataset contains
three bands, three attributes are created (b0, b1 and b2).
- -i filename,
--input filename
- Raster input dataset containing band information
- -s sample,
--sample sample
- Raster dataset with categorical values to sample the input raster dataset.
Output will contain features with input band information included.
- -ln layer,
--ln layer
- Layer name(s) in sample (leave empty to select all)
- -rand number,
--random number
- Create simple random sample of points. Provide number of points to
generate
- -grid size,
--grid size
- Create systematic grid of points. Provide cell grid size (in projected
units, e.g,. m)
- -o filename,
--output filename
- Output sample dataset
- -c class,
--class class
- Class(es) to extract from input sample image. Leave empty to extract all
valid data pixels from sample dataset. Make sure to set classes if rule is
set to mode, proportion or count.
- -t threshold,
--threshold threshold
- Probability threshold for selecting samples (randomly). Provide
probability in percentage (>0) or absolute (<0). Use a single
threshold per vector sample layer. If using raster land cover maps as a
sample dataset, you can provide a threshold value for each class (e.g.
-t 80 -t 60). Use value 100 to select all
pixels for selected class(es)
- -f format, --f
format
- Output sample dataset format
- -ft fieldType,
--ftype fieldType
- Field type (only Real or Integer)
- -lt labelType,
--ltype labelType
- Label type: In16 or String
- -b band, --band
band
- Band index(es) to extract. Leave empty to use all bands
- -sband band,
--startband band
- Start band sequence number
- -eband band,
--endband band
- End band sequence number
- -bndnodata
band, --bndnodata band
- Band(s) in input image to check if pixel is valid (used for
srcnodata)
- -srcnodata
value, --srcnodata value
- Invalid value(s) for input image
- -bn attribute,
--bname attribute
- For single band input data, this extra attribute name will correspond to
the raster values. For multi-band input data, multiple attributes with
this prefix will be added (e.g. b0, b1, b2, etc.)
- -cn attribute,
--cname attribute
- Name of the class label in the output vector dataset
- -down value,
--down value
- Down sampling factor
- -v level,
--verbose level
- Verbose mode if > 0