Voxel - Revision history

Neteler: /* Introduction */

2022-04-21T09:52:53Z

Introduction

← Older revision		Revision as of 09:52, 21 April 2022
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	=== Introduction ===		=== Introduction ===

	For an overview, see in the manual the summary page {{cmd\|raster3dintro}}.		For an overview, see in the manual the '''raster3d summary page {{cmd\|raster3dintro}}'''.

	:[[Image:chal3d_i.gif]] [[Image:chal4d_i.gif]]		:[[Image:chal3d_i.gif]] [[Image:chal4d_i.gif]]

Neteler: Various updates

2022-04-21T09:52:26Z

Various updates

← Older revision		Revision as of 09:52, 21 April 2022
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	GRASS GIS is one of the few GIS with volume data support. Here data are stored as a 3D raster with a unit volume called a voxel (volume pixel). Voxels are designed to support for example representations of trivariate continuous fields.		GRASS GIS is one of the few GIS with volume data support. Here data are stored as a 3D raster with a unit volume called a voxel (volume pixel). Voxels are designed to support for example representations of trivariate continuous fields.

	=== Import or ~~creating~~ of volumes ===		=== Introduction ===

			For an overview, see in the manual the summary page {{cmd\|raster3dintro}}.

			:[[Image:chal3d_i.gif]] [[Image:chal4d_i.gif]]
			:[[Image:nviz_isosurf3d_small.jpg]]

			=== Import or creation of volumes ===

	'''From 3D point data:'''		'''From 3D point data:'''

	You can import 3D ASCII raster data in GRASS voxel format using {{cmd\|r3.in.ascii}} or {{cmd\|r3.in.xyz}}. ~~Note~~:		You can import 3D ASCII raster data in GRASS voxel format using {{cmd\|r3.in.ascii}} or {{cmd\|r3.in.xyz}}. There are different possibilities:
	* For ''r3.in.ascii'' the data need to be plain and properly ordered value data with a header (see the manual for the format).		* For ''r3.in.ascii'' the data need to be plain and properly ordered value data with a header (see the manual for the format).
	* In case of regular 3D data (x,y,z,value) in a CSV style file, use ''r3.in.xyz'' with method "mean". This only works properly when one value falls into a target voxel.		* In case of regular 3D data (x,y,z,value) in a CSV style file, use ''r3.in.xyz'' with method "mean". This only works properly when one value falls into a target voxel.
			* Import x,y,z,... data as 3D with the {{cmd\|v.in.ascii}} "-z" flag and "z=" column parameter (see below for voxel interpolation):
			v.in.ascii -z format=point cat=1 x=2 y=3 z=4
			* You can convert a 2D vector into a 3D vector with {{cmd\|v.extrude}} (take elevation values from vector attribute column) or {{cmd\|v.drape}} (interpolate elevation values from a raster DEM map) - see below for voxel interpolation.

	'''From 2D raster maps:'''		'''From 2D raster maps:'''
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	=== Voxel operations ===		=== Voxel operations ===

	~~Powerful 3D map algebra is implemented in {{cmd\|r3.mapcalc}}.~~		Among other functionalities, there are available:

	A 3D groundwater flow model is implement in {{cmd\|r3.gwflow}}.		* Powerful '''3D map algebra''' is implemented in {{cmd\|r3.mapcalc}}.
			* '''Cross-sections''' can be generated with {{cmd\|r3.cross.rast}}.
			* Voxels can be '''interpolated''' from 3D point dat from {{cmd\|v.vol.rst}}.
			* A '''3D groundwater flow model''' is implement in {{cmd\|r3.gwflow}}.

	~~Cross-sections can be generated with~~ {{cmd\|~~r3.cross.rast}}.~~		See also the {{cmd\|raster3dintro}} for more details.

	~~Voxels can be interpolated from 3D point dat from {{cmd\|v.vol.rst~~}}.

	=== Voxel statistics ===		=== Voxel statistics ===
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	[[Image:LausanneDemoDataset3dParaview_10.png\|thumb\|center\|400px\|3D groundwater flow]]		[[Image:LausanneDemoDataset3dParaview_10.png\|thumb\|center\|400px\|3D groundwater flow]]

			=== Region settings ===
			Region settings are handled by the {{cmd\|g.region}} module.
			Special 3D raster controls for {{cmd\|g.region}} <code>-p3</code> include:

			-3 flag: Prints 3D settings
			rast3d Set region to match this 3D raster map (both 2D and 3D values)
			t Value for the top edge
			b Value for the bottom edge
			res3 3D grid resolution (north-south, east-west and top-bottom)
			tbres Top-bottom grid resolution 3D
			<!-- (??) 3dview Set region to match this 3dview file -->

			=== Worksflows ===

			From the mailing list: [https://lists.osgeo.org/pipermail/grass-user/2006-April/033602.html Raster 3D from DEMs (drillhole data)].

	== Technical details of implementation ==		== Technical details of implementation ==

Neteler: remove hardcoded version specific urls, use latest version

2018-12-04T10:53:57Z

remove hardcoded version specific urls, use latest version

← Older revision		Revision as of 10:53, 4 December 2018
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	'''From 3D point data:'''		'''From 3D point data:'''

	You can import 3D ASCII raster data in GRASS voxel format using {{cmd\|r3.in.ascii}} or {{cmd\|r3.in.xyz~~\|version=70~~}} ~~(in GRASS 6 an Addon)~~. Note:		You can import 3D ASCII raster data in GRASS voxel format using {{cmd\|r3.in.ascii}} or {{cmd\|r3.in.xyz}}. Note:
	* For ''r3.in.ascii'' the data need to be plain and properly ordered value data with a header (see the manual for the format).		* For ''r3.in.ascii'' the data need to be plain and properly ordered value data with a header (see the manual for the format).
	* In case of regular 3D data (x,y,z,value) in a CSV style file, use ''r3.in.xyz'' with method "mean". This only works properly when one value falls into a target voxel.		* In case of regular 3D data (x,y,z,value) in a CSV style file, use ''r3.in.xyz'' with method "mean". This only works properly when one value falls into a target voxel.

Neteler: +Comments from Soeren Gebbert on grass-dev, Jun 25, 2013

2013-06-27T21:37:22Z

+Comments from Soeren Gebbert on grass-dev, Jun 25, 2013

← Older revision		Revision as of 21:37, 27 June 2013
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	[[Image:LausanneDemoDataset3dParaview_10.png\|thumb\|center\|400px\|3D groundwater flow]]		[[Image:LausanneDemoDataset3dParaview_10.png\|thumb\|center\|400px\|3D groundwater flow]]

			== Technical details of implementation ==

			The 3D raster (voxel) implementation in GRASS GIS is using a tiled based storage approach (see related page in the [http://grass.osgeo.org/programming7/raster3dlib.html Programmer's Manual]).
			The tiles can be stored in compressed form (zlib in GRASS7) or uncompressed form on the hard disk. Usually you store them in compressed form. Hence in case you have many tiles that are empty or have equal data, the compression is very high. GRASS can handle 3D raster maps up to hundreds of GB in size. The main memory is not an issue when processing 3D raster maps, since only a limited number of tiles is read into main memory at runtime. You can specify the tile size of each 3D raster map that you create. Hence you can adjust it to the needs of , e.g. soil depths resolution.

			In addition you can specify a 3D raster mask that works pretty the same way as masks in the raster approach in GRASS GIS.

	== See also ==		== See also ==

⚠️HamishBowman: /* Visualization */

2013-05-30T02:51:24Z

Visualization

← Older revision		Revision as of 02:51, 30 May 2013
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	=== Visualization ===		=== Visualization ===

	The [[NVIZ]] n-dimensional viewer supports voxel visualization. As an alternative, you can use the external Paraview application, see [[GRASS and Paraview]]:		The [[NVIZ]] ''n''-dimensional viewer supports voxel visualization. As an alternative, you can use the external Paraview application, see [[GRASS and Paraview]]:

	[[Image:LausanneDemoDataset3dParaview_4.png\|thumb\|center\|400px\|3D groundwater flow]]		[[Image:LausanneDemoDataset3dParaview_4.png\|thumb\|center\|400px\|3D groundwater flow]]

⚠️HamishBowman: /* Visualization */

2013-05-30T02:51:10Z

Visualization

← Older revision		Revision as of 02:51, 30 May 2013
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	=== Visualization ===		=== Visualization ===

	The ~~{{cmd\|nviz}}~~ viewer supports voxel visualization. As an alternative, you can use the external Paraview application, see [[GRASS and Paraview]]:		The [[NVIZ]] n-dimensional viewer supports voxel visualization. As an alternative, you can use the external Paraview application, see [[GRASS and Paraview]]:

	[[Image:LausanneDemoDataset3dParaview_4.png\|thumb\|center\|400px\|3D groundwater flow]]		[[Image:LausanneDemoDataset3dParaview_4.png\|thumb\|center\|400px\|3D groundwater flow]]

Neteler: + GRASS and Paraview

2012-12-03T14:38:37Z

+ GRASS and Paraview

← Older revision		Revision as of 14:38, 3 December 2012
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	[[Image:LausanneDemoDataset3dParaview_10.png\|thumb\|center\|400px\|3D groundwater flow]]		[[Image:LausanneDemoDataset3dParaview_10.png\|thumb\|center\|400px\|3D groundwater flow]]

	=== See also ===		== See also ==

	* [[Help with 3D]]		* [[Help with 3D]]
			* [[GRASS and Paraview]]

	[[Category: Documentation]]		[[Category: Documentation]]
	[[Category: Visualization]]		[[Category: Visualization]]
	[[Category: Voxel]]		[[Category: Voxel]]

Neteler: /* Visualization */

2012-11-30T12:53:26Z

Visualization

← Older revision		Revision as of 12:53, 30 November 2012
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	[[Image:LausanneDemoDataset3dParaview_10.png\|thumb\|center\|400px\|3D groundwater flow]]		[[Image:LausanneDemoDataset3dParaview_10.png\|thumb\|center\|400px\|3D groundwater flow]]

			=== See also ===

			* [[Help with 3D]]

			[[Category: Documentation]]
			[[Category: Visualization]]
			[[Category: Voxel]]

Neteler: /* Import or creating of volumes */

2012-11-21T22:04:29Z

Import or creating of volumes

← Older revision		Revision as of 22:04, 21 November 2012
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	'''From 3D point data:'''		'''From 3D point data:'''

	You can import 3D ASCII raster data in GRASS voxel format using {{cmd\|r3.in.ascii}} or {{cmd\|r3.in.xyz}}. Note:		You can import 3D ASCII raster data in GRASS voxel format using {{cmd\|r3.in.ascii}} or {{cmd\|r3.in.xyz\|version=70}} (in GRASS 6 an Addon). Note:
	* For ''r3.in.ascii'' the data need to be plain and properly ordered value data with a header (see the manual for the format).		* For ''r3.in.ascii'' the data need to be plain and properly ordered value data with a header (see the manual for the format).
	* In case of regular 3D data (x,y,z,value) in a CSV style file, use ''r3.in.xyz'' with method "mean". This only works properly when one value falls into a target voxel.		* In case of regular 3D data (x,y,z,value) in a CSV style file, use ''r3.in.xyz'' with method "mean". This only works properly when one value falls into a target voxel.

Neteler: more explanations

2012-11-21T21:51:26Z

more explanations

← Older revision		Revision as of 21:51, 21 November 2012
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	=== Import or creating of volumes ===		=== Import or creating of volumes ===

	You can import 3D ASCII raster data in GRASS voxel format using {{cmd\|r3.in.ascii}}. You can also create a volume raster model based on 2D raster data by converting 2D raster slices into 3D raster or a 3D volume map based on 2D elevation and value raster maps.		'''From 3D point data:'''

			You can import 3D ASCII raster data in GRASS voxel format using {{cmd\|r3.in.ascii}} or {{cmd\|r3.in.xyz}}. Note:
			* For ''r3.in.ascii'' the data need to be plain and properly ordered value data with a header (see the manual for the format).
			* In case of regular 3D data (x,y,z,value) in a CSV style file, use ''r3.in.xyz'' with method "mean". This only works properly when one value falls into a target voxel.


			'''From 2D raster maps:'''

			You can also create a volume raster model based on 2D raster data by converting 2D raster slices into 3D raster or a 3D volume map based on 2D elevation and value raster maps.

	See the {{cmd\|raster3dintro}} for more details.		See the {{cmd\|raster3dintro}} for more details.