Re: [GRASS-dev] how to reproject a raster map with absolute numbers without losing data

Moritz Lennert wrote: > > For anything other than lat-lon locations, G_area_of_cell_at_row() > > assumes that the area of a cell is constant over the region. That's > > true for equal-area projections, and not far off for small scales > > (where projection would be almost an affine

Re: [GRASS-dev] how to reproject a raster map with absolute numbers without losing data

Le 8 décembre 2016 07:25:46 GMT+01:00, Glynn Clements a écrit : > >Moritz Lennert wrote: > >> Yes. Do we have any existing module to calculate area by pixel ? An >> area() function in r.mapcalc would be nice... > >I notice that this has been added, but I'm not sure

Re: [GRASS-dev] how to reproject a raster map with absolute numbers without losing data

Moritz Lennert wrote: > Yes. Do we have any existing module to calculate area by pixel ? An > area() function in r.mapcalc would be nice... I notice that this has been added, but I'm not sure that it's adequate for this task. For anything other than lat-lon locations, G_area_of_cell_at_row()

Re: [GRASS-dev] how to reproject a raster map with absolute numbers without losing data

On Fri, Dec 2, 2016 at 11:19 AM, Moritz Lennert < mlenn...@club.worldonline.be> wrote: > > On 01/12/16 14:31, Markus Metz wrote: [...] >> >> In theory, a higher target resolution should result in a higher total >> sum, a lower target resolution in a lower total sum. > > > Why is that if we work in

Re: [GRASS-dev] how to reproject a raster map with absolute numbers without losing data

On 02/12/16 11:53, Paulo van Breugel wrote: On 02-12-16 11:19, Moritz Lennert wrote: On 01/12/16 14:31, Markus Metz wrote: On Thu, Dec 1, 2016 at 1:16 PM, Paulo van Breugel > wrote: On 01-12-16 12:01, Moritz Lennert wrote: On

Re: [GRASS-dev] how to reproject a raster map with absolute numbers without losing data

On 01/12/16 15:13, Markus Metz wrote: On Thu, Dec 1, 2016 at 12:01 PM, Moritz Lennert > wrote: On 30/11/16 09:40, Paulo van Breugel wrote: On Tue, Nov 29, 2016 at 5:44 PM, Moritz Lennert > An area() function in

Re: [GRASS-dev] how to reproject a raster map with absolute numbers without losing data

On 02-12-16 11:19, Moritz Lennert wrote: On 01/12/16 14:31, Markus Metz wrote: On Thu, Dec 1, 2016 at 1:16 PM, Paulo van Breugel > wrote: On 01-12-16 12:01, Moritz Lennert wrote: On 30/11/16 09:40, Paulo van Breugel wrote: On

Re: [GRASS-dev] how to reproject a raster map with absolute numbers without losing data

On 01/12/16 14:31, Markus Metz wrote: On Thu, Dec 1, 2016 at 1:16 PM, Paulo van Breugel > wrote: On 01-12-16 12:01, Moritz Lennert wrote: On 30/11/16 09:40, Paulo van Breugel wrote: On Tue, Nov 29, 2016 at 5:44 PM, Moritz Lennert

Re: [GRASS-dev] how to reproject a raster map with absolute numbers without losing data

On Thu, Dec 1, 2016 at 12:01 PM, Moritz Lennert < mlenn...@club.worldonline.be> wrote: > > On 30/11/16 09:40, Paulo van Breugel wrote: >> >> >>> On Tue, Nov 29, 2016 at 5:44 PM, Moritz Lennert > > >>> >>> > An area() function in r.mapcalc would be nice... [...] > >> |r.mapcalc "rcs =

Re: [GRASS-dev] how to reproject a raster map with absolute numbers without losing data

On Thu, Dec 1, 2016 at 2:31 PM, Markus Metz wrote: > > > On Thu, Dec 1, 2016 at 1:16 PM, Paulo van Breugel > wrote: > > > > > > > > On 01-12-16 12:01, Moritz Lennert wrote: > >> > >> On 30/11/16 09:40, Paulo van Breugel wrote: > >>> > >>> >

Re: [GRASS-dev] how to reproject a raster map with absolute numbers without losing data

On Thu, Dec 1, 2016 at 1:16 PM, Paulo van Breugel wrote: > > > > On 01-12-16 12:01, Moritz Lennert wrote: >> >> On 30/11/16 09:40, Paulo van Breugel wrote: >>> >>> On Tue, Nov 29, 2016 at 5:44 PM, Moritz Lennert >> >> > An area() function in r.mapcalc would

Re: [GRASS-dev] how to reproject a raster map with absolute numbers without losing data

On 01-12-16 12:01, Moritz Lennert wrote: On 30/11/16 09:40, Paulo van Breugel wrote: On Tue, Nov 29, 2016 at 5:44 PM, Moritz Lennert > An area() function in r.mapcalc would be nice... Would indeed be a nice addition, but it isn't too difficult to compute, using: |g.region

Re: [GRASS-dev] how to reproject a raster map with absolute numbers without losing data

On 30/11/16 09:40, Paulo van Breugel wrote: On Tue, Nov 29, 2016 at 5:44 PM, Moritz Lennert > An area() function in r.mapcalc would be nice... Would indeed be a nice addition, but it isn't too difficult to compute, using: |g.region rast=afripop10@PERMANENT| |PI=3.1415926536| |export

Re: [GRASS-dev] how to reproject a raster map with absolute numbers without losing data

On 01/12/16 08:49, Markus Metz wrote: r.to.vect converts only non-null cells, no mask needed, at least for me in trunk. Weird, I waws convinced that I saw otherwise before, but now I can confirm. Sorry for the noise... >2. reproject these vector points to the target location I locally

Re: [GRASS-dev] how to reproject a raster map with absolute numbers without losing data

On Wed, Nov 30, 2016 at 7:35 PM, Moritz Lennert < mlenn...@club.worldonline.be> wrote: > > > > Le 29 novembre 2016 22:33:39 GMT+01:00, Markus Metz < markus.metz.gisw...@gmail.com> a écrit : > > For > >reprojection, something like r.in.xyz could work: > > I'm currently going through this process

Re: [GRASS-dev] how to reproject a raster map with absolute numbers without losing data

Hei, What about something like this (example converts from UTM33 to WGS84 and creates ): r.stats -gn1 INPUTMAP | cs2cs -E -f "%.6f" +proj=utm +no_defs +zone=33 +a=6378137 +rf=298.257222101 +towgs84=0.000,0.000,0.000 +to_meter=1 +to +proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs | tr '\t' ' '

Re: [GRASS-dev] how to reproject a raster map with absolute numbers without losing data

-Original Message- From: Moritz Lennert [mailto:mlenn...@club.worldonline.be] Sent: torsdag 1. desember 2016 00.01 >> >>BTW, I think several modules would benefit from a -b do not build >>topology... >Which other modules are you thinking about? >Moritz All modules which produce

Re: [GRASS-dev] how to reproject a raster map with absolute numbers without losing data

Le 30 novembre 2016 21:05:18 GMT+01:00, "Blumentrath, Stefan" a écrit : >Hei, > >What about something like this (example converts from UTM33 to WGS84 >and creates ): >r.stats -gn1 INPUTMAP | cs2cs -E -f "%.6f" +proj=utm +no_defs +zone=33 >+a=6378137

Re: [GRASS-dev] how to reproject a raster map with absolute numbers without losing data

Le 29 novembre 2016 22:33:39 GMT+01:00, Markus Metz a écrit : > For >reprojection, something like r.in.xyz could work: I'm currently going through this process and it raises a series of issues: > >1. convert raster cells to vector points with raster cell value

Re: [GRASS-dev] how to reproject a raster map with absolute numbers without losing data

On Wed, Nov 30, 2016 at 2:12 PM, Markus Metz wrote: > > > On Wed, Nov 30, 2016 at 1:22 PM, Moritz Lennert < > mlenn...@club.worldonline.be> wrote: > > > > On 30/11/16 09:40, Paulo van Breugel wrote: > >> > >> > >> > >> On 29-11-16 22:33, Markus Metz wrote: > >>> >

Re: [GRASS-dev] how to reproject a raster map with absolute numbers without losing data

On Wed, Nov 30, 2016 at 1:22 PM, Moritz Lennert < mlenn...@club.worldonline.be> wrote: > > On 30/11/16 09:40, Paulo van Breugel wrote: >> >> >> >> On 29-11-16 22:33, Markus Metz wrote: >>> >>> >>> >>> On Tue, Nov 29, 2016 at 5:44 PM, Moritz Lennert >>>

Re: [GRASS-dev] how to reproject a raster map with absolute numbers without losing data

On 30/11/16 09:40, Paulo van Breugel wrote: On 29-11-16 22:33, Markus Metz wrote: On Tue, Nov 29, 2016 at 5:44 PM, Moritz Lennert > wrote: > > > > Le 29 novembre 2016 15:10:11 GMT+01:00, Markus Metz

Re: [GRASS-dev] how to reproject a raster map with absolute numbers without losing data

On 29-11-16 22:33, Markus Metz wrote: On Tue, Nov 29, 2016 at 5:44 PM, Moritz Lennert > wrote: > > > > Le 29 novembre 2016 15:10:11 GMT+01:00, Markus Metz

Re: [GRASS-dev] how to reproject a raster map with absolute numbers without losing data

On Tue, Nov 29, 2016 at 5:44 PM, Moritz Lennert < mlenn...@club.worldonline.be> wrote: > > > > Le 29 novembre 2016 15:10:11 GMT+01:00, Markus Metz < markus.metz.gisw...@gmail.com> a écrit : > >On Mon, Nov 28, 2016 at 5:51 PM, Moritz Lennert < > >mlenn...@club.worldonline.be> wrote: > >> > >> Hi, >

Re: [GRASS-dev] how to reproject a raster map with absolute numbers without losing data

Le 29 novembre 2016 15:10:11 GMT+01:00, Markus Metz a écrit : >On Mon, Nov 28, 2016 at 5:51 PM, Moritz Lennert < >mlenn...@club.worldonline.be> wrote: >> >> Hi, >> >> In discussions with students the following problem has arisen, and >I'm >not sure how to respond

Re: [GRASS-dev] how to reproject a raster map with absolute numbers without losing data

On Mon, Nov 28, 2016 at 5:51 PM, Moritz Lennert < mlenn...@club.worldonline.be> wrote: > > Hi, > > In discussions with students the following problem has arisen, and I'm not sure how to respond to this: > > When reprojecting raster data, one has to chose a method of interpolation. However, when