pkdiff(1)

NAME
pkdiff - program to compare two raster image files

SYNOPSIS
pkdiff
-i input -ref reference [options] [advanced options]

DESCRIPTION
pkdiff compares two datasets. The reference can either be a raster or a vector, but the input must be a raster dataset. In case the reference is a raster dataset, a pixel by pixel comparison is performed. With no further options, the utility reports if the rasters are identical or different. If required, an output raster dataset can be written with a qualitative information per pixel: 0 (input=reference), 1 (input>reference) or 2 (input<reference). If, however, the reference is a vector dataset, it must consist of point features. Polygon features are automatically converted to the centroid points before analyzing.

A typical use of the utility is to assess the accuracy of an input raster land cover map, based on a reference vector dataset. The reference dataset must contain an attribute (label) for each class. A confusion matrix is produced if the option \FC-cm\F[]|\FC--confusion\F[] is set. Here too, an output dataset can be written, which will be a vector dataset in this case. It contains the reference feature points with the extracted data value of the raster input dataset as a new attribute.

OPTIONS

\FC-i\F[] filename, \FC--input\F[] filename
    Input raster dataset.

\FC-ref\F[] filename, \FC--reference\F[] filename
    Reference (raster or vector) dataset

\FC-ln\F[] layer, \FC--ln\F[] layer
    Layer name(s) in sample. Leave empty to select all (for vector reference datasets only)

\FC-b\F[] band, \FC--band\F[] band
    Input raster band

\FC-cm\F[], \FC--confusion\F[]
    Create confusion matrix (to stdout)

\FC-lr\F[] attribute, \FC--lref\F[] attribute
    Attribute name of the reference label (for vector reference datasets only)

\FC-c\F[] name, \FC--class\F[] name
    List of class names.

\FC-r\F[] value, \FC--reclass\F[] value
    List of class values (use same order as in classname option).

\FC-nodata\F[] value, \FC--nodata\F[] value
    No data value(s) in input or reference dataset are ignored

\FC-m\F[] mask, \FC--mask\F[] mask
    Use the first band of the specified file as a validity mask. Nodata values can be set with the option \FC--msknodata\F[].

\FC-msknodata\F[] value, \FC--msknodata\F[] value
    Mask value(s) where image is invalid. Use negative value for valid data (example: use \FC-t\F[] \FC-1\F[]: if only \FC-1\F[] is valid value)

\FC-v\F[] level, \FC--verbose\F[] level
    verbose level

Advanced options

\FC-o\F[] output, \FC--output\F[] output
    Output dataset (optional)

\FC-f\F[] OGRformat, \FC--f\F[] OGRformat
    OGR format for output vector (for vector reference datasets only)

\FC-of\F[] GDALformat, \FC--oformat\F[] GDALformat
    Output image format (see also gdal_translate(1)). Empty string: inherit from input image

\FC-lc\F[] attribute, \FC--lclass\F[] attribute
    Attribute name of the classified label (for vector reference datasets only)

\FC--commission\F[] value
    Value for commission errors: input label < reference label

\FC-bnd\F[] value, \FC--boundary\F[] value
    Boundary for selecting the sample (for vector reference datasets only)

\FC-hom\F[], \FC--homogeneous\F[]
    Only take regions with homogeneous boundary into account (for reference datasets only)

\FC-circ\F[], \FC--circular\F[]
    Use circular boundary (for vector reference datasets only)

\FC-ct\F[] colortable, \FC--ct\F[] colortable
    Color table in ASCII format having 5 columns: id R G B ALFA (0: transparent, 255: solid).

\FC-co\F[] NAME=VALUE, \FC--co\F[] NAME=VALUE
    Creation option for output file. Multiple options can be specified.

EXAMPLE
Check if two raster images are different (reports only if images are different or not)

\FC
pkdiff -i input.tif -ref reference.tif
      \F[]

Validate a classification map using points from a reference sample and report confusion matrix

\FC
pkdiff -i classificationMap.tif -ref referencePoints.tif -cm
      \F[]