3.4.6.5. Reclassification

_images/reclassification_tab.png — Reclassification

This tab allows for the reclassification (i.e. assigning a new class code to raster pixels). In particular, it eases the conversion from C ID to MC ID values.

This tool supports virtual raster output; if the output file name ends with .vrt then the output is created as virtual raster composed of as many .tif files as the number of CPU threads defined in System; for large rasters this can speed up the process.

Порада

Information about APIs of this tool in Remotior Sensus at this link .

3.4.6.5.1. Cross classification 

Tool symbol and name	Description
Select the classification	select a classification raster (already loaded in QGIS)
	refresh layer list

3.4.6.5.2. Values 

Tool symbol and name	Description
calculate C ID to MC ID values	if checked, the reclassification table is filled according to the ROI & Signature list when Calculate unique values is clicked
Calculate unique values	calculate unique values in the classification and fill the reclassification table
Incremental new values	calculate a new incremental value (e.g. 1, 2, 3, …) for every old value and fill the reclassification table
	add a row to the table
	remove highlighted rows from the table
	import rules from a text file .csv separated by comma having the following structure `Old_value,New_value` (where Old_value cam be also an expression and New_value is an integer value) for instance:: raster < 1,1 (raster > 1) & (raster < 3),2 raster < 3,3
	export the reclassification table to a text file (.csv) that can be imported later

The reclassification table is structured with the following fields.

Old value	New value
value or expression defining old values to be reclassified	integer value for the corresponding `Old value`

Old value can be a value or an expressions defined using the variable name raster (custom names can be defined in Variable name for expressions ), following Python operators (e.g.:

raster > 3 select all pixels having value > 3 ;
(raster > 5) | (raster < 2) select all pixels having value > 5 or < 2 ;
(raster >= 2) & (raster <= 5) select all pixel values between 2 and 5.

3.4.6.5.3. Symbology 

Tool symbol and name	Description
Use code from Signature list	if checked, color and class information are defined from ROI & Signature list: `MC ID`: use the ID of macroclasses `C ID`: use the ID of classes