Description Usage Arguments Details Value References Examples

This function supports calculating texture statistics derived from grey-level co-occurrence matrices (GLCMs). The default textures are calculated using a 45 degree shift. See Details for other options.

1 2 3 4 |

`x` |
a |

`n_grey` |
number of grey levels to use in texture calculation |

`window` |
the window size to consider for texture calculation as a two element integer vector (number of rows, number of columns) |

`shift` |
a list or matrix specifying the shift to use. See Details. |

`statistics` |
A list of GLCM texture measures to calculate (see Details). |

`min_x` |
minimum value of input |

`max_x` |
maximum value of input |

`na_opt` |
How to handle NA values in |

`na_val` |
the value to use to fill NA values on edges of |

`scale_factor` |
factor by which to multiply results. Useful if rounding
results to integers (see |

`asinteger` |
whether to round results to nearest integer. Can be used to
save space by saving results as, for example, an 'INT2S' |

The `statistics`

parameter should be a list, and can include any (one
or more) of the following: 'mean', 'mean_ENVI', 'variance', 'variance_ENVI',
'homogeneity', 'contrast', 'dissimilarity', 'entropy', 'second_moment',
and/or 'correlation'. By default all of the statistics except for
"mean_ENVI" and "variance_ENVI" will be returned .

`shift`

can be one of:

a two element integer vector giving the shift (Q in Gonzalez and Woods, 2008), as (number of rows, number of columns).

a list of integer vectors of length 2 specifying multiple (row, col) shifts over which to calculate the GLCM textures. For example:

`shift=list(c(1,1), c(-1,-1))`

a matrix with two columns specifying, in rows, multiple (row, col) shifts over which to calculate the GLCM textures. For example:

`shift=matrix(c(1,1,-1,-1), byrow=TRUE, ncol=2)`

If multiple shifts are supplied, `glcm`

will calculate each texture
statistic using all the specified shifts, and return the mean value of the
texture for each pixel. To calculate GLCM textures over "all directions" (in
the terminology of commonly used remote sensing software), use:
`shift=list(c(0,1), c(1,1), c(1,0), c(1,-1))`

. This will calculate the
average GLCM texture using shifts of 0 degrees, 45 degrees,
90 degrees, and 135 degrees.

A `RasterLayer`

or `RasterStack`

with the requested GLCM
texture measures.

Lu, D., and M. Batistella. 2005. Exploring TM image texture and its relationships with biomass estimation in Rondônia, Brazilian Amazon. Acta Amazonica 35:249–257.

Gonzalez, R. C. 2008. Digital image processing. 3rd ed. Prentice Hall, Upper Saddle River, N.J, pages 830–836.

Haralick, R. M., K. Shanmugam, and I. Dinstein. 1973. Textural features for image classification. IEEE Transactions on Systems, Man and Cybernetics SMC-3:610–621.

Pratt, W. K. 2007. Digital image processing: PIKS Scientific inside. 4th ed. Wiley-Interscience, Hoboken, N.J pages 540–541, 563–566.

1 2 3 4 5 6 7 8 9 10 11 12 | ```
## Not run:
require(raster)
# Calculate GLCM textures using default 90 degree shift
textures_shift1 <- glcm(raster(L5TSR_1986, layer=1))
plot(textures_shift1)
# Calculate GLCM textures over all directions
textures_all_dir <- glcm(raster(L5TSR_1986, layer=1),
shift=list(c(0,1), c(1,1), c(1,0), c(1,-1)))
plot(textures_all_dir)
## End(Not run)
``` |

Embedding an R snippet on your website

Add the following code to your website.

For more information on customizing the embed code, read Embedding Snippets.