GRASS raster semantics - Revision history

Neteler: link to source code updated

2022-02-07T12:31:47Z

link to source code updated

← Older revision		Revision as of 12:31, 7 February 2022
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	* '''DOUBLE MAP''': see DCELL DATA TYPE		* '''DOUBLE MAP''': see DCELL DATA TYPE

	(reference in the [https://github.com/OSGeo/grass/blob/~~master~~/include/gis.h~~#L588~~ GRASS GIS source code])		(reference in the [https://github.com/OSGeo/grass/blob/main/include/grass/gis.h GRASS GIS source code, around line 613])

	==Region Calculations==		==Region Calculations==

⚠️El selvaje: adding Float32 range-bound

2021-02-27T13:59:23Z

adding Float32 range-bound

← Older revision		Revision as of 13:59, 27 February 2021
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	== Raster map precision types ==		== Raster map precision types ==

	* '''CELL DATA TYPE''': a raster map from INTEGER type (4 bytes, whole numbers only)		* '''CELL DATA TYPE''': a raster map from INTEGER type (4 bytes, whole numbers only).
	** in GRASS GIS, CELL is a 32 bit integer with a range from -2,147,483,647 to +2,147,483,647. The value -2,147,483,648 is reserved for NODATA.		** In GRASS GIS, CELL is a 32 bit integer with a range from -2,147,483,647 to +2,147,483,647. The value -2,147,483,648 is reserved for NODATA.
	* '''FCELL DATA TYPE''': a raster map from FLOAT type (4 bytes, 7-9 digits precision)		* '''FCELL DATA TYPE''': a raster map from FLOAT type (4 bytes, 7-9 digits precision).
	* '''DCELL DATA TYPE''': a raster map from DOUBLE type (8 bytes, 15-17 digits precision)		** In GRASS GIS, FCELL is a 32 bit float (Float32) with a range from -3.4E38 to 3.4E38. However, the integer precision can be only ensured between -16777216 and 16777216. If your raster overpass this range we strongly suggest to use DCELL, as Float64 data type.
	* '''NULL''': represents "no data" in raster maps, to be distinguished from 0 (zero) data value		* '''DCELL DATA TYPE''': a raster map from DOUBLE type (8 bytes, 15-17 digits precision).
			** In GRASS GIS, DCELL is a 64 bit float (Float64) with a range from -1.79E308 to 1.79E308.
			* '''NULL''': represents "no data" in raster maps, to be distinguished from 0 (zero) data value.

			Aliases:
	* '''INTEGER MAP''': see CELL DATA TYPE		* '''INTEGER MAP''': see CELL DATA TYPE
	* '''FLOAT MAP''': see FCELL DATA TYPE		* '''FLOAT MAP''': see FCELL DATA TYPE

Neteler: +reference in the GRASS GIS source code)

2019-09-27T12:59:48Z

+reference in the GRASS GIS source code)

← Older revision		Revision as of 12:59, 27 September 2019
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	* '''FLOAT MAP''': see FCELL DATA TYPE		* '''FLOAT MAP''': see FCELL DATA TYPE
	* '''DOUBLE MAP''': see DCELL DATA TYPE		* '''DOUBLE MAP''': see DCELL DATA TYPE

			(reference in the [https://github.com/OSGeo/grass/blob/master/include/gis.h#L588 GRASS GIS source code])

	==Region Calculations==		==Region Calculations==

Neteler: more details about CELL type added

2019-09-27T11:47:46Z

more details about CELL type added

← Older revision		Revision as of 11:47, 27 September 2019
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	== Raster map precision types ==		== Raster map precision types ==

	* '''CELL DATA TYPE''': a raster map from INTEGER type (whole numbers only)		* '''CELL DATA TYPE''': a raster map from INTEGER type (4 bytes, whole numbers only)
			** in GRASS GIS, CELL is a 32 bit integer with a range from -2,147,483,647 to +2,147,483,647. The value -2,147,483,648 is reserved for NODATA.
	* '''FCELL DATA TYPE''': a raster map from FLOAT type (4 bytes, 7-9 digits precision)		* '''FCELL DATA TYPE''': a raster map from FLOAT type (4 bytes, 7-9 digits precision)
	* '''DCELL DATA TYPE''': a raster map from DOUBLE type (8 bytes, 15-17 digits precision)		* '''DCELL DATA TYPE''': a raster map from DOUBLE type (8 bytes, 15-17 digits precision)

Neteler: +:Category:Raster

2019-09-27T09:52:19Z

+:Category:Raster

← Older revision		Revision as of 09:52, 27 September 2019
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	[[Category: FAQ]]		[[Category: FAQ]]
	[[Category: Interpolation]]		[[Category: Interpolation]]
			[[Category:Raster]]

Neteler: link to progman

2015-07-20T09:03:19Z

link to progman

← Older revision		Revision as of 09:03, 20 July 2015
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	== Handling of NULL values ==		== Handling of NULL values ==

			=== General remarks ===

			The NULL (no data) handling depends on the map precision type. See for details
			* http://grass.osgeo.org/programming7/rasterlib.html#Null_no_data

	=== {{cmd\|r.mapcalc}} ===		=== {{cmd\|r.mapcalc}} ===
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	processing. You can either replace the nulls in an existing map using		processing. You can either replace the nulls in an existing map using
	e.g. "r.null null=0", or adjust the tests within r.mapcalc		e.g. "r.null null=0", or adjust the tests within r.mapcalc


	== Arithmetic operations ==		== Arithmetic operations ==

Neteler: /* Resampling */

2015-07-20T08:57:19Z

Resampling

← Older revision		Revision as of 08:57, 20 July 2015
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	==Resampling==		==Resampling==

			(see also [[Interpolation#Resampling_methods_and_interpolation_in_GRASS]])

	The built-in nearest-neighbour resampling of raster data calculates		The built-in nearest-neighbour resampling of raster data calculates

Neteler: +Raster map precision types

2014-09-11T14:38:41Z

+Raster map precision types

← Older revision		Revision as of 14:38, 11 September 2014
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	A quick summary c/o Glynn Clements:		A quick summary c/o Glynn Clements:

			== Raster map precision types ==

			* '''CELL DATA TYPE''': a raster map from INTEGER type (whole numbers only)
			* '''FCELL DATA TYPE''': a raster map from FLOAT type (4 bytes, 7-9 digits precision)
			* '''DCELL DATA TYPE''': a raster map from DOUBLE type (8 bytes, 15-17 digits precision)
			* '''NULL''': represents "no data" in raster maps, to be distinguished from 0 (zero) data value

			* '''INTEGER MAP''': see CELL DATA TYPE
			* '''FLOAT MAP''': see FCELL DATA TYPE
			* '''DOUBLE MAP''': see DCELL DATA TYPE

	==Region Calculations==		==Region Calculations==

Neteler: prettify

2014-09-11T14:36:01Z

prettify

← Older revision		Revision as of 14:36, 11 September 2014
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	==Region Calculations==		==Region Calculations==

	~~Well,~~ the region isn't limited to raster data; it may also affect some		The "current region" or "computational region" is the actual setting of the region boundaries and the actual raster resolution. Note that the computational region isn't limited to raster data; it may also affect some
	vector operations.		vector operations.

	The region's bounds describe a rectangle in two-dimensional space. For		The computational region's bounds describe a rectangle in two-dimensional space. For
	raster operations, this rectangle is subdivided into a grid of		raster operations, this rectangle is subdivided into a grid of
	rectangular cells, so the region's bounds are aligned with the edges		rectangular cells, so the region's bounds are aligned with the edges
	of the outermost cells.		of the outermost cells.

			For details, see [[Computational region]].

	==Cell Locations==		==Cell Locations==

Neteler: +Arithmetic operations

2012-01-12T20:33:56Z

+Arithmetic operations

← Older revision		Revision as of 20:33, 12 January 2012
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	processing. You can either replace the nulls in an existing map using		processing. You can either replace the nulls in an existing map using
	e.g. "r.null null=0", or adjust the tests within r.mapcalc		e.g. "r.null null=0", or adjust the tests within r.mapcalc


			== Arithmetic operations ==

			r.mapcalc: Arithmetic operations on mixed types promote the lesser type to the greater type, where CELL < FCELL < DCELL:

			<source lang="bash">
			\| CELL FCELL DCELL
			------+------------------
			CELL \| CELL FCELL DCELL
			FCELL \| FCELL FCELL DCELL
			DCELL \| DCELL DCELL DCELL
			</source>

	==Developer Notes Rules==		==Developer Notes Rules==
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	[[Category:FAQ]]		[[Category: FAQ]]
	[[Category: Interpolation]]		[[Category: Interpolation]]