GRIB - Revision history

Neteler: updated

2016-10-31T10:47:59Z

updated

← Older revision		Revision as of 10:47, 31 October 2016
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	** http://www.raymarine.com/default.aspx?site=1&section=3&page=149		** http://www.raymarine.com/default.aspx?site=1&section=3&page=149
	** http://www.navcenter.com/newdwnld.ccml		** http://www.navcenter.com/newdwnld.ccml
			** https://www.ncdc.noaa.gov/data-access/model-data/model-datasets/global-forcast-system-gfs

	* GRIB data viewer:		* GRIB data viewer:
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	~~Newer versions of~~ [http://www.gdal.org GDAL] can read this data, and it can be imported with {{cmd\|r.in.gdal}}.		[http://www.gdal.org GDAL] can read this data, and it can be imported with {{cmd\|r.in.gdal}}.

	* '''''Make sure you are using GDAL version 1.10 or newer due to bugs in earlier versions of GDAL's GRIB driver.'''''		* '''''Make sure you are using GDAL version 1.10 or newer due to bugs in earlier versions of GDAL's GRIB driver.'''''

	It often contains a small number of cells but many many bands (layers).		GRIB files often contains a small number of cells but many many bands (layers).

	View band metadata with <tt>gdalinfo</tt>.		View band metadata with <tt>gdalinfo</tt>.
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	To remove any tiny rings and slivers you can add a length column in the contours map with {{cmd\|v.db.~~addcol~~}}, populate the column with line length using the {{cmd\|v.to.db}} module, and finally extract only lines with a length greater than some threshold with a SQL query to {{cmd\|v.extract}}.		To remove any tiny rings and slivers you can add a length column in the contours map with {{cmd\|v.db.addcolumn}}, populate the column with line length using the {{cmd\|v.to.db}} module, and finally extract only lines with a length greater than some threshold with a SQL query to {{cmd\|v.extract}}.

	=== Automation ===		=== Automation ===

Neteler: updated

2016-10-31T09:55:56Z

updated

← Older revision		Revision as of 09:55, 31 October 2016
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	* Some data available here:		* Some data available here:
	** http://www.globalmarinenet.~~net~~/grib~~.htm~~		** http://www.globalmarinenet.com/free-grib-file-downloads/
	** http://www.raymarine.com/default.aspx?site=1&section=3&page=149		** http://www.raymarine.com/default.aspx?site=1&section=3&page=149
	** http://www.navcenter.com/newdwnld.ccml		** http://www.navcenter.com/newdwnld.ccml
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	Convert U,V velocity component maps into magnitude, direction maps for use with d.rast.arrow:		Convert U,V velocity component maps into magnitude, direction maps for use with d.rast.arrow:
	g.copy TasmanSea.wind.u_wind_latest,U_map		g.copy raster=TasmanSea.wind.u_wind_latest,U_map
	g.copy TasmanSea.wind.v_wind_latest,V_map		g.copy raster=TasmanSea.wind.v_wind_latest,V_map

	g.region ~~rast~~=TasmanSea.wind.u_wind_latest -p		g.region raster=TasmanSea.wind.u_wind_latest -p
	r.mapcalc 'magnitude = sqrt(U_map^2 + V_map^2)'		r.mapcalc 'magnitude = sqrt(U_map^2 + V_map^2)'
	r.colors magnitude col=bcyr		r.colors magnitude col=bcyr
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	Display:		Display:
	d.mon x0		d.mon wx0
	d.rast magnitude		d.rast magnitude
	d.vect admin98 type=~~area fcol=225:225:255 color=none~~		d.vect admin98 type=boundary

	d.rast.arrow map=direction type=grass magnitude_map=magnitude grid=none ~~arrow~~=black		d.rast.arrow map=direction type=grass magnitude_map=magnitude grid=none color=black

	d.legend map="magnitude" at=90.3,94.7,1.8,26.5		d.legend map="magnitude" at=90.3,94.7,1.8,26.5

⚠️HamishBowman: /* Processing */

2014-02-14T01:34:44Z

Processing

← Older revision		Revision as of 01:34, 14 February 2014
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	The data is in Lat/Lon on a Sphere. It is not quite correct to import into a Lat/Lon WGS84 location, but the resolution is so crude that you might be able to hold your nose and do so anyway.		The data is in Lat/Lon on a Sphere. It is not quite correct to import into a Lat/Lon WGS84 location, but the resolution is so crude that you might be able to hold your nose and do so anyway.

	* ''There is a cell-registration bug in GDAL: (grid vs cell-center convention) cells ~~are~~ all offset to the east and south by half a cell. ~~You~~ can fix this by hand with the {{cmd\|r.region}} module. See:''		* ''There was a cell-registration bug in GDAL older than version 1.10: (grid vs cell-center convention) cells were all offset to the east and south by half a cell. If you are stuck with an old version of GDAL you can fix this by hand with the {{cmd\|r.region}} module. See:''
	: https://trac.osgeo.org/gdal/ticket/2550		: https://trac.osgeo.org/gdal/ticket/2550
	: https://trac.osgeo.org/gdal/ticket/2637 # '''Note''': these 2 bugs appear now closed and fixed		: https://trac.osgeo.org/gdal/ticket/2637 # '''Note''': these 2 bugs appear now closed and fixed

⚠️HamishBowman: /* GDAL bug workaround */

2014-02-14T01:33:40Z

GDAL bug workaround

← Older revision		Revision as of 01:33, 14 February 2014
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	==== GDAL bug workaround ====		==== GDAL bug workaround ====

	* Versions of GDAL '''prior''' to 1.10 had a 1/2 cell registration bug. It is fixed now in newer versions of GDAL.		* Versions of GDAL '''prior''' to 1.10 had a 1/2 cell registration bug. It is fixed now in newer versions of GDAL. What follows is a work-around for that old bug:

	<source lang="bash">		<source lang="bash">

⚠️HamishBowman: /* GDAL bug workaround */

2014-02-14T01:32:54Z

GDAL bug workaround

← Older revision		Revision as of 01:32, 14 February 2014
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	==== GDAL bug workaround ====		==== GDAL bug workaround ====

			* Versions of GDAL '''prior''' to 1.10 had a 1/2 cell registration bug. It is fixed now in newer versions of GDAL.

	<source lang="bash">		<source lang="bash">
	g.region rast=mapname		g.region rast=mapname

⚠️HamishBowman: /* GRIB data */ version warning

2014-02-14T01:31:26Z

GRIB data: version warning

← Older revision		Revision as of 01:31, 14 February 2014
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	Newer versions of [http://www.gdal.org GDAL] can read this data ~~(i.e. newer than the 1.5 branch; SVN trunk is best)~~, and it can be imported with {{cmd\|r.in.gdal}}.		Newer versions of [http://www.gdal.org GDAL] can read this data, and it can be imported with {{cmd\|r.in.gdal}}.

			* '''''Make sure you are using GDAL version 1.10 or newer due to bugs in earlier versions of GDAL's GRIB driver.'''''

	It often contains a small number of cells but many many bands (layers).		It often contains a small number of cells but many many bands (layers).

⚠️Madi at 09:50, 3 May 2013

2013-05-03T09:50:03Z

← Older revision		Revision as of 09:50, 3 May 2013
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	[[Category:Documentation]]		[[Category:Documentation]]
	[[Category:Tutorial]]		[[Category:Tutorial]]
			[[Category:Grib]]

⚠️Madi: /* Processing */

2013-03-22T13:36:12Z

Processing

← Older revision		Revision as of 13:36, 22 March 2013
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	* ''There is a cell-registration bug in GDAL: (grid vs cell-center convention) cells are all offset to the east and south by half a cell. You can fix this by hand with the {{cmd\|r.region}} module. See:''		* ''There is a cell-registration bug in GDAL: (grid vs cell-center convention) cells are all offset to the east and south by half a cell. You can fix this by hand with the {{cmd\|r.region}} module. See:''
	: https://trac.osgeo.org/gdal/ticket/2550		: https://trac.osgeo.org/gdal/ticket/2550
	: https://trac.osgeo.org/gdal/ticket/2637 # Note: these bugs appear now closed and fixed		: https://trac.osgeo.org/gdal/ticket/2637 # '''Note''': these 2 bugs appear now closed and fixed
	: GRASS's [[Grid registration]] wiki page for a general discussion		: GRASS's [[Grid registration]] wiki page for a general discussion

⚠️Madi: /* Processing */

2013-03-22T13:35:45Z

Processing

← Older revision		Revision as of 13:35, 22 March 2013
Line 31:		Line 31:
	* ''There is a cell-registration bug in GDAL: (grid vs cell-center convention) cells are all offset to the east and south by half a cell. You can fix this by hand with the {{cmd\|r.region}} module. See:''		* ''There is a cell-registration bug in GDAL: (grid vs cell-center convention) cells are all offset to the east and south by half a cell. You can fix this by hand with the {{cmd\|r.region}} module. See:''
	: https://trac.osgeo.org/gdal/ticket/2550		: https://trac.osgeo.org/gdal/ticket/2550
	: https://trac.osgeo.org/gdal/ticket/2637		: https://trac.osgeo.org/gdal/ticket/2637 # Note: these bugs appear now closed and fixed
	: GRASS's [[Grid registration]] wiki page for a general discussion		: GRASS's [[Grid registration]] wiki page for a general discussion

⚠️Madi: /* GDAL bug workaround */

2012-07-30T09:49:33Z

GDAL bug workaround

← Older revision		Revision as of 09:49, 30 July 2012
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	Convert U,V velocity component maps into ~~magnitide~~,direction maps for use with d.rast.arrow:		Convert U,V velocity component maps into magnitude, direction maps for use with d.rast.arrow:
	g.copy TasmanSea.wind.u_wind_latest,U_map		g.copy TasmanSea.wind.u_wind_latest,U_map
	g.copy TasmanSea.wind.v_wind_latest,V_map		g.copy TasmanSea.wind.v_wind_latest,V_map
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	Resulting image:		Resulting image:
	: [[Image:TasmanSea winds latest.jpg]]		: [[Image:TasmanSea winds latest.jpg]]


	==== Create contours ====		==== Create contours ====