Enables calculation of image textures derived from grey-level co-occurrence matrices (GLCMs). Supports processing images that cannot fit in memory.
glcm package enables calculating image textures derived from grey-level
co-occurrence matrics (GLCMs) in R. The texture calculation is coded in C++
to optimize computation time. The
glcm function in the package can compute
the following texture statistics: mean (using either of two definitions),
variance (using either of two definitions), homogeneity, contrast,
dissimilarity, entropy, second_moment, and, correlation. The window size,
shift, and grey-level quantization are user determined. See the help file for
glcm (included in the package) for details.
To install the latest stable version of
CRAN, fire up R and run:
If you want the very latest version of
glcm, you can install the development
version. Be aware this version might not install as it is not as well tested as
the stable version.
NOTE: If you are installing on Windows, you will need to install the
appropriate version of Rtools
for your version of R (as
glcm contains C++ code) before you follow the
The easiest way to install the development version of the
glcm package is
devtools package by Hadley
Wickham. After installing
devtools from CRAN, type:
Tropical Ecology Assessment and Monitoring (TEAM) Network
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Arlington, VA 22202
Docs for "glcm" stated that the default direction was 90 degrees. This is incorrect - the default is 45 degrees. Fixed docs accordingly.
Fix error that arose when handling large images due to usage of "stack" from wrong namespace in "glcm" function. Thanks to Wenjuan Shen, Dennis O. Ojwang', and others for reporting.
Fix handling of images small enough to process as a single block.
Fix case of very small final block.
Misc doc fixes and CRAN check fixes.
Support calculation of average textures over multiple shifts (glcm in "all directions". Thanks to Matthias Weigand for testing.
Automatically process rasters block-by-block when cannot process in memory.
Thanks to Santosh Bhandari for testing.
Upgrade to roxygen2 > 4.0.2.
Various minor doc fixes.
Fix proj4string for example image.
Upgrade to roxygen2 > 4.0.0.
Reformat tests for
testthat >= 0.8.
Fix handling of window sizes other than 3 x 3 (issue #2).
Rename test image to end in 3x3_1x1 (as it was run with a 3x3 window size and 1 row x 1 column shift).
Add additional test cases.
Add additional validation of user input to "glcm" function.
Update website address.
Various fixes to docs.
Require Rcpp >= 0.11.0 (as Makevars and Makevars.win are no longer included in package).
Minor fixes to docs.