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CorrelIM: Images correlation
Access this help text as a web page: CorrelIM
Presentation and options
This application adjusts a regression line between the values of the first raster, which acts as an independent variable, and the second raster, which acts as a dependent variable. This adjustment gives rise to the corresponding correlation coefficient r (Spiegel 1991, 2nd edition, McGraw-Hill) and defines the slope and the independent term that characterize the correlation between the two variables. The application can do this calculation globally or regionally:
Global correlation:
In this option the adjustment is generated for the entire envelope of the raster.
Correlation by areas:
The calculation is performed by defining a side of a window (in number of cells) that will allow to obtain the correlation by square zones of size WindowSide x WindowSide. In this second case it generates an output raster with the correlation coefficient of each window in which it has done the calculation, and with a cell side that is the product of the window side by the pixel side of the input rasters. If the number of columns and/or rows in the input rasters is not multiple on the window side, the program ignores the cells at the right and/or lower ends of the raster.
In the two operating options of the application (global or by areas) the two rasters must have the same cell side, scope and horizontal reference system.
Dialog box of the application
Syntax
Syntax:
- CorrelIM 1 Raster1 Raster2 Report /HISTO_BI
- CorrelIM 2 Raster1 Raster2 Result WindowSide /HISTO_BI
Options:
- 1:
Global correlation.
- 2:
Correlation by areas.
Parameters:
- Raster1
(Raster 1 -
Input parameter): It is the raster that acts as an independent variable.
- Raster2
(Raster 2 -
Input parameter): It is the raster that acts as a dependent variable.
- Report
(Report -
Output parameter): It is a text file that reports the results of the adjustment.
- Result
(Result -
Output parameter): It is the name of the output raster file in option 2, where each pixel will contain the linear correlation coefficient corresponding to each independent setting of each window.
- WindowSide
(Side of the window -
Input parameter): It is the parameter that indicates the side, in pixels, of the window that defines the areas of regionalization.
Modifiers:
/HISTO_BI= (Two-dimensional histogram) Name of the file resulting from generating a two-dimensional histogram. (Output parameter)
