Re: [GRASS-user] Searching for technical details on how v.rast.stats calculates means and other statistics
On Sun, Feb 22, 2015 at 8:36 AM, RichardCooper richtcoo...@hotmail.com wrote: I've resolved - I hadn't set g.region aligning to the raster prior to v.to.rast: g.region -a res=0.22 does not align the region to the raster, but to the resolution. This is an important difference reflected in the results Markus M This appears to work,with outputs from r.univar matching v.rast.stats: g.region -p -a raster=cahpa_i0apr_05216_nc_remapped_nc_1@prcp05216ijk res=0.22 g.region -p align=cahpa_i0apr_05216_nc_remapped_nc_1@prcp05216ijk v.to.rast --overwrite input=BMR_bndry_epsg4326@prcp05216ijk type=area output=BMR_bndry_epsg4326_rasterized use=cat r.univar -g -t map=cahpa_i0apr_05216_nc_remapped_nc_1@prcp05216ijk zones=BMR_bndry_epsg4326_rasterized@prcp05216ijk v.rast.stats map=BMR_bndry_epsg4326@prcp05216ijk raster=cahpa_i0apr_05216_nc_remapped_nc_1@prcp05216ijk column_prefix=test method=number,minimum,maximum,range,average,sum -- View this message in context: http://osgeo-org.1560.x6.nabble.com/Searching-for-technical-details-on-how-v-rast-stats-calculates-means-and-other-statistics-tp5188809p5189189.html Sent from the Grass - Users mailing list archive at Nabble.com. ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Searching for technical details on how v.rast.stats calculates means and other statistics
Hi Markus, Thanks for your comments. It still appears that v.rast.stats is giving me different values to r.univar. Essentially I'd like to clarify how the values are derived from v.rast.stats. I'm guessing that the discrepancy between my r.univar and v.rast.stats outputs relates to how I'm using g.region? The following shows my approach for deriving statistics from both r.univar and v.rast.stats. Cheers, Richard 1. Using r.univar and zones to output stats # set g.region for rasterizing vector g.region -p -a vector=BMR_bndry_epsg4326@prcp05216ijk res=0.22 projection: 3 (Latitude-Longitude) zone: 0 datum: wgs84 ellipsoid: wgs84 north: 14:31:12N south: 13:12N west: 99:39:36E east: 101:12E nsres: 0:13:12 ewres: 0:13:12 rows: 6 cols: 7 cells: 42 # rasterize vector to be used for zones v.to.rast --overwrite input=BMR_bndry_epsg4326@prcp05216ijk type=area output=BMR_bndry_epsg4326_rasterized use=cat Reading areas... Reading features... Writing raster map... Converted areas: 6 of 0 v.to.rast complete. # set g.region for zones with r.univar g.region -p rast=BMR_bndry_epsg4326_rasterized@prcp05216ijk projection: 3 (Latitude-Longitude) zone: 0 datum: wgs84 ellipsoid: wgs84 north: 14:31:12N south: 13:12N west: 99:39:36E east: 101:12E nsres: 0:13:12 ewres: 0:13:12 rows: 6 cols: 7 cells: 42 g.region -p align=cahpa_i0apr_05216_nc_remapped_nc_1@prcp05216ijk projection: 3 (Latitude-Longitude) zone: 0 datum: wgs84 ellipsoid: wgs84 north: 14:35:24N south: 13:03N west: 99:34:12E east: 101:19:48E nsres: 0:13:12 ewres: 0:13:12 rows: 7 cols: 8 cells: 56 r.univar -g -t map=cahpa_i0apr_05216_nc_remapped_nc_1@prcp05216ijk zones=BMR_bndry_epsg4326_rasterized@prcp05216ijk zone|label|non_null_cells|null_cells|min|max|range|mean|mean_of_abs|stddev|variance|coeff_var|sum|sum_abs 1|Category 1|4|0|3.58209799742326e-05|7.74326545069925e-05|4.16116745327599e-05|5.64720030524768e-05|5.64720030524768e-05|1.53324774982512e-05|2.35084866234379e-10|27.1505820043313|0.000225888012209907|0.000225888012209907 2|Category 2|2|0|3.53023679053877e-05|6.23035812168382e-05|2.70012133114506e-05|4.88029745611129e-05|4.88029745611129e-05|1.35006066557253e-05|1.82266380072614e-10|27.6634913694027|9.7605949159e-05|9.7605949159e-05 3|Category 3|1|0|8.14341983641498e-05|8.14341983641498e-05|0|8.14341983641498e-05|8.14341983641498e-05|0|0|0|8.14341983641498e-05|8.14341983641498e-05 4|Category 4|3|0|5.68314899282996e-05|8.2188387750648e-05|2.53568978223484e-05|6.57776896938837e-05|6.57776896938837e-05|1.16198714234862e-05|1.35021411898352e-10|17.6653687254186|0.000197333069081651|0.000197333069081651 5|Category 5|4|0|3.15697689075023e-05|4.9253627366852e-05|1.76838584593497e-05|3.7798413359269e-05|3.7798413359269e-05|7.09251495570204e-06|5.03037683968571e-11|18.7640546926894|0.000151193653437076|0.000151193653437076 6|Category 6|1|0|1.89598704309901e-05|1.89598704309901e-05|0|1.89598704309901e-05|1.89598704309901e-05|0|0|0|1.89598704309901e-05|1.89598704309901e-05 (Sun Feb 22 13:23:02 2015) Command finished (0 sec) 2. Check outputs against v.to.rast # set g.region for raster (stats to be derived from this layer): g.region -p -a raster=cahpa_i0apr_05216_nc_remapped_nc_1@prcp05216ijk res=0.22 projection: 3 (Latitude-Longitude) zone: 0 datum: wgs84 ellipsoid: wgs84 north: 35:38:24N south: 15:10:48S west: 89:45:36E east: 140:34:48E nsres: 0:13:12 ewres: 0:13:12 rows: 231 cols: 231 cells: 53361 v.rast.stats map=BMR_bndry_epsg4326@prcp05216ijk raster=cahpa_i0apr_05216_nc_remapped_nc_1@prcp05216ijk column_prefix=teststat method=number,minimum,maximum,range,average,sum Outputs from attribute table: cat,province,teststat_number,teststat_minimum,teststat_maximum,teststat_range,teststat_average,teststat_sum 1,krung_thep_maha_nakhon_bangkok,2,3.58209799742326e-05,6.23035812168382e-05,2.64826012426056e-05,4.90622805955354e-05,9.81245611910708e-05 2,samut_prakan,1,3.53023679053877e-05,3.53023679053877e-05,0,3.53023679053877e-05,3.53023679053877e-05 3,nonthaburi,2,5.02148177474737e-05,8.14341983641498e-05,3.12193806166761e-05,6.58245080558117e-05,0.000131649016111623 4,pathum_thani,3,4.46328085672576e-05,8.2188387750648e-05,3.7791833904e-05,6.12175620820684e-05,0.000183652686246205 5,nakhon_pathom,3,3.81464305974077e-05,6.24195599812083e-05,2.42731293838006e-05,4.99398726484893e-05,0.000149819617945468 6,samut_sakhon,2,1.89598704309901e-05,7.74326545069925e-05,5.84727840760024e-05,4.81962624689913e-05,9.63925249379827e-05 -- View this message in context: http://osgeo-org.1560.x6.nabble.com/Searching-for-technical-details-on-how-v-rast-stats-calculates-means-and-other-statistics-tp5188809p5189188.html Sent from the
Re: [GRASS-user] Searching for technical details on how v.rast.stats calculates means and other statistics
I've resolved - I hadn't set g.region aligning to the raster prior to v.to.rast: This appears to work,with outputs from r.univar matching v.rast.stats: g.region -p -a raster=cahpa_i0apr_05216_nc_remapped_nc_1@prcp05216ijk res=0.22 g.region -p align=cahpa_i0apr_05216_nc_remapped_nc_1@prcp05216ijk v.to.rast --overwrite input=BMR_bndry_epsg4326@prcp05216ijk type=area output=BMR_bndry_epsg4326_rasterized use=cat r.univar -g -t map=cahpa_i0apr_05216_nc_remapped_nc_1@prcp05216ijk zones=BMR_bndry_epsg4326_rasterized@prcp05216ijk v.rast.stats map=BMR_bndry_epsg4326@prcp05216ijk raster=cahpa_i0apr_05216_nc_remapped_nc_1@prcp05216ijk column_prefix=test method=number,minimum,maximum,range,average,sum -- View this message in context: http://osgeo-org.1560.x6.nabble.com/Searching-for-technical-details-on-how-v-rast-stats-calculates-means-and-other-statistics-tp5188809p5189189.html Sent from the Grass - Users mailing list archive at Nabble.com. ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Searching for technical details on how v.rast.stats calculates means and other statistics
On Fri, Feb 20, 2015 at 12:33 PM, RichardCooper richtcoo...@hotmail.com wrote: I seem to be getting an error with r.univar when using a zone file. I run, g.region as follows: g.region -a raster=cahpa_i0apr_05216_nc_remapped_nc_1@prcp05216ijk res=0.22 When you use g.region -a res=, the new computational region is most probably not identical to the raster's grid geometry. Better just use g.region -a raster=cahpa_i0apr_05216_nc_remapped_nc_1@prcp05216ijk res=0.22 If you are interested in stats for zones, you could do g.region rast=zones g.region align=cover in your case g.region rast=BMR_bndry_epsg4326_rasterized@prcp05216ijk g.region align=cahpa_i0apr_05216_nc_remapped_nc_1@prcp05216ijk HTH, Markus M Then r.univar (see below). There are 6 categories in the zone file, but r.univar reports null cells for category 1? Initially I thought it was me not setting g.region correctly, but I can't seem to get it to work as expected. Any ideas would be welcome. Cheers, Richard r.univar map=cahpa_i0apr_05216_nc_remapped_nc_1@prcp05216ijk zones=BMR_bndry_epsg4326_rasterized@prcp05216ijk zone 1 Category 1 total null and non-null cells: 4 total null cells: 0 Of the non-null cells: -- n: 4 minimum: 3.5821e-05 maximum: 7.74327e-05 range: 4.16117e-05 mean: 5.6472e-05 mean of absolute values: 5.6472e-05 standard deviation: 1.53325e-05 variance: 2.35085e-10 variation coefficient: 27.1506 % sum: 0.000225888012209907 zone 2 Category 2 total null and non-null cells: 2 total null cells: 0 Of the non-null cells: -- n: 2 minimum: 3.53024e-05 maximum: 6.23036e-05 range: 2.70012e-05 mean: 4.8803e-05 mean of absolute values: 4.8803e-05 standard deviation: 1.35006e-05 variance: 1.82266e-10 variation coefficient: 27.6635 % sum: 9.7605949159e-05 zone 3 Category 3 total null and non-null cells: 1 total null cells: 0 Of the non-null cells: -- n: 1 minimum: 8.14342e-05 maximum: 8.14342e-05 range: 0 mean: 8.14342e-05 mean of absolute values: 8.14342e-05 standard deviation: 0 variance: 0 variation coefficient: 0 % sum: 8.14341983641498e-05 zone 4 Category 4 total null and non-null cells: 3 total null cells: 0 Of the non-null cells: -- This is my zones file: Type of Map: raster Number of Categories: 6 | Data Type:CELL | Rows: 231 | Columns: 231 | Total Cells: 53361 |Projection: Latitude-Longitude |N: 35:38:24NS: 15:10:48S Res: 0:13:12 |E: 140:34:48EW: 89:45:36E Res: 0:13:12 | Range of data:min = 1 max = 6 | | Data Source: |Vector Map: BMR_bndry_epsg4326@prcp05216ijk |Original scale from vector map: 1:1 | | Data Description: |generated by v.to.rast | | Comments: |v.to.rast input=BMR_bndry_epsg4326@prcp05216ijk layer=1 type=ar\ |ea output=BMR_bndry_epsg4326_rasterized use=cat value=1 memory=\ |300 | This is the raster file: Type of Map: raster Number of Categories: 0 | Data Type:FCELL | Rows: 230 | Columns: 230 | Total Cells: 52900 |Projection: Latitude-Longitude |N: 35:29:24NS: 15:06:36S Res: 0:13:12 |E: 140:29:24EW: 89:53:24E Res: 0:13:12 | Range of data:min = 0 max = 0.002821672 | -- View this message in context: http://osgeo-org.1560.x6.nabble.com/Searching-for-technical-details-on-how-v-rast-stats-calculates-means-and-other-statistics-tp5188809p5188865.html Sent from the Grass - Users mailing list archive at Nabble.com. ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Searching for technical details on how v.rast.stats calculates means and other statistics
On 20/02/15 12:33, RichardCooper wrote: I seem to be getting an error with r.univar when using a zone file. I run, g.region as follows: g.region -a raster=cahpa_i0apr_05216_nc_remapped_nc_1@prcp05216ijk res=0.22 What does g.region -p show ? Then r.univar (see below). There are 6 categories in the zone file, but r.univar reports null cells for category 1? Initially I thought it was me not setting g.region correctly, but I can't seem to get it to work as expected. What does r.univar just on each map separately show ? Moritz ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Searching for technical details on how v.rast.stats calculates means and other statistics
The output from g.region: g.region -p projection: 3 (Latitude-Longitude) zone: 0 datum: wgs84 ellipsoid: wgs84 north: 35:38:24N south: 15:10:48S west: 89:45:36E east: 140:34:48E nsres: 0:13:12 ewres: 0:13:12 rows: 231 cols: 231 cells: 53361 This is r.univar without the zone file: r.univar map=cahpa_i0apr_05216_nc_remapped_nc_1@prcp05216ijk total null and non-null cells: 53361 total null cells: 16564 Of the non-null cells: -- n: 36797 minimum: 0 maximum: 0.00282167 range: 0.00282167 mean: 7.79549e-05 mean of absolute values: 7.79549e-05 standard deviation: 0.000106692 variance: 1.13832e-08 variation coefficient: 136.864 % sum: 2.86850755307868 (Fri Feb 20 21:41:59 2015) Command finished (0 sec) Please also see my earlier comment, where I edited the previous message: copied here: I'll need to check again, but there seems to be a mismatch between categories reported in r.univar and the actual category in the zone file. E.g. category 2 reported by r.univar is derived from category 1 of the zones file? -- View this message in context: http://osgeo-org.1560.x6.nabble.com/Searching-for-technical-details-on-how-v-rast-stats-calculates-means-and-other-statistics-tp5188809p5188937.html Sent from the Grass - Users mailing list archive at Nabble.com. ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
