[GRASS-dev] new addon: v.what.rast.multi

GRASS GRASS developer
1

Hi all,

FYI I just submitted my (first!) GRASS add-on, called v.what.rast.multi 0.

It is a super simple Python wrapper around v.what.rast, and allows to query a suite of rasters in one go:

v.what.rast.multi map=mygeodetic_pts raster=elev_state_500m,slope,aspect columns=elevation,slope,aspect

Cheers,

Pierre

2

I guess I probably should have added the URL: https://trac.osgeo.org/grass/browser/grass-addons/grass7/vector/v.what.rast.multi

Apologies!

···

On 8 May 2017 at 17:16, Pierre Roudier <pierre.roudier@gmail.com> wrote:

Hi all,

FYI I just submitted my (first!) GRASS add-on, called v.what.rast.multi 0.

It is a super simple Python wrapper around v.what.rast, and allows to query a suite of rasters in one go:

v.what.rast.multi map=mygeodetic_pts raster=elev_state_500m,slope,aspect columns=elevation,slope,aspect

Cheers,

Pierre

3

On 08/05/17 07:16, Pierre Roudier wrote:

Hi all,

FYI I just submitted my (first!) GRASS add-on, called v.what.rast.multi [0].

It is a super simple Python wrapper around v.what.rast, and allows to
query a suite of rasters in one go:

v.what.rast.multi map=mygeodetic_pts raster=elev_state_500m,slope,aspect
columns=elevation,slope,aspect

Very useful, thanks !

Don't forget to add the addon to the Makefile in the grass-addons/grass7/vector directory.

Moritz

4

Done – thanks for the heads-up Moritz!

···

On 8 May 2017 at 23:05, Moritz Lennert <mlennert@club.worldonline.be> wrote:

On 08/05/17 07:16, Pierre Roudier wrote:

Hi all,

FYI I just submitted my (first!) GRASS add-on, called v.what.rast.multi [0].

It is a super simple Python wrapper around v.what.rast, and allows to
query a suite of rasters in one go:

v.what.rast.multi map=mygeodetic_pts raster=elev_state_500m,slope,aspect
columns=elevation,slope,aspect

Very useful, thanks !

Don’t forget to add the addon to the Makefile in the grass-addons/grass7/vector directory.

Moritz

5

Very Nice!!

I have one question: Because it is called v.what.rast.multi and not r.what.rast.multi?

Best

···

2017-05-08 18:25 GMT-03:00 Pierre Roudier <pierre.roudier@gmail.com>:

Done – thanks for the heads-up Moritz!

grass-dev mailing list
grass-dev@lists.osgeo.org
https://lists.osgeo.org/mailman/listinfo/grass-dev

–

On 8 May 2017 at 23:05, Moritz Lennert <mlennert@club.worldonline.be> wrote:

On 08/05/17 07:16, Pierre Roudier wrote:

Hi all,

FYI I just submitted my (first!) GRASS add-on, called v.what.rast.multi [0].

It is a super simple Python wrapper around v.what.rast, and allows to
query a suite of rasters in one go:

v.what.rast.multi map=mygeodetic_pts raster=elev_state_500m,slope,aspect
columns=elevation,slope,aspect

Very useful, thanks !

Don’t forget to add the addon to the Makefile in the grass-addons/grass7/vector directory.

Moritz

Pablo J. Zader
Universidad Nacional de Córdoba

GIS and remote sensing developer
–

Lic. en Cs. de la Computación

Mgtr. en Aplicaciones Espaciales de Alerta y Respuesta Temprana a Emergencias
–
pablo.zader@gmail.com

"Los Grandes Hombres hablan sobre ideas…
Los Hombres Promedio hablan sobre cosas…
Los Hombres Pequeños hablan… de otros Hombres.

del libro Matemática estas ahi? A. Paenza "

6

On 8 May 2017 at 07:16, Pierre Roudier <pierre.roudier@gmail.com> wrote:

Hi all,

Hi,

FYI I just submitted my (first!) GRASS add-on, called v.what.rast.multi [0].

It is a super simple Python wrapper around v.what.rast, and allows to query
a suite of rasters in one go:

thanks, it is useful
to improve a little bit, you add multiprocessing to the module, for
example a process for each raster

Cheers,

Pierre

--
ciao
Luca

www.lucadelu.org

7

On 09/05/17 07:26, pablo zader wrote:

Very Nice!!

I have one question: Because it is called v.what.rast.multi and not
r.what.rast.multi?

It is a frontend to v.what.rast which loads information from a raster map into the attribute table of a point vector map. As it is the vector map which is modified, it is considered a vector module.

Moritz

8

Hi Pierre,

I have one question about the code. In lines 126-130 you create an object 'fl', which you subsequently do not seem to use. Perhaps in line 150 it should be flags=fl ?

Something else, last year I wrote an addon r.what.rastlabel (https://github.com/ecodiv/GRASS-scripts/tree/master/v.what.rastlabel) which can be used to (multiple) raster values and labels. Optionally, it can also upload raster values only, like your addon (that part uses the same approach you use). I have not yet added it to the grass addon repository. I might do that later, at which point we can also see if it makes sense to merge the two.

Cheers,

Paulo

On 5/9/17 8:36 AM, Luca Delucchi wrote:

On 8 May 2017 at 07:16, Pierre Roudier <pierre.roudier@gmail.com> wrote:

Hi all,

Hi,

FYI I just submitted my (first!) GRASS add-on, called v.what.rast.multi [0].

It is a super simple Python wrapper around v.what.rast, and allows to query
a suite of rasters in one go:

thanks, it is useful
to improve a little bit, you add multiprocessing to the module, for
example a process for each raster

Interesting, could help to speed up with large point data layers.

Cheers,

Pierre

9

Hello Pierre,

Thanks for this new add-on! Comes on time for me :slight_smile:

I’m testing it and I have observed something odd.
I’m querying integer maps but v.what.rast.multi gives me float values. I run v.what.rast and I get the proper integer values. Does it have anything to do with what Paulo just pointed out?

Thanks much!

Vero

···

2017-05-09 9:30 GMT+02:00 Paulo van Breugel <p.vanbreugel@gmail.com>:

Hi Pierre,

I have one question about the code. In lines 126-130 you create an object ‘fl’, which you subsequently do not seem to use. Perhaps in line 150 it should be flags=fl ?

Something else, last year I wrote an addon r.what.rastlabel (https://github.com/ecodiv/GRASS-scripts/tree/master/v.what.rastlabel) which can be used to (multiple) raster values and labels. Optionally, it can also upload raster values only, like your addon (that part uses the same approach you use). I have not yet added it to the grass addon repository. I might do that later, at which point we can also see if it makes sense to merge the two.

Cheers,

Paulo

On 5/9/17 8:36 AM, Luca Delucchi wrote:

On 8 May 2017 at 07:16, Pierre Roudier <pierre.roudier@gmail.com> wrote:

Hi all,

Hi,

FYI I just submitted my (first!) GRASS add-on, called v.what.rast.multi [0].

It is a super simple Python wrapper around v.what.rast, and allows to query
a suite of rasters in one go:

thanks, it is useful
to improve a little bit, you add multiprocessing to the module, for
example a process for each raster

Interesting, could help to speed up with large point data layers.

Cheers,

Pierre

grass-dev mailing list
grass-dev@lists.osgeo.org
https://lists.osgeo.org/mailman/listinfo/grass-dev

10

On 09/05/17 14:37, Veronica Andreo wrote:

Hello Pierre,

Thanks for this new add-on! Comes on time for me :slight_smile:

I'm testing it and I have observed something odd.
I'm querying integer maps but v.what.rast.multi gives me float values. I
run v.what.rast and I get the proper integer values. Does it have
anything to do with what Paulo just pointed out?

The module just loops over a series of v.what.rast calls, so results should not be different. If any, Paulo's point reinforces this as the '-i' flag (i.e.interpolate nearest points) is never used...

And I cannot confirm:

g.region rast=elev_ned_30m
v.random test npoints=500
r.mapcalc "srtm = int(elev_srtm_30m)"
r.mapcalc "ned = int(elev_ned_30m)"
v.what.rast.multi map=test raster=elev_srtm_30m,elev_ned_30m,srtm,ned columns=srtm_float,ned_float,srtm_int,ned_int
v.db.select test col=srtm_float,ned_float,srtm_int,ned_int
[...]
105.1695|103.4447|104|102
124.6583|122.6958|124|122
104.6636|93.28199|104|93
81.77528|79.49014|81|78
90.53698|86.29738|89|85
80.44241|76.85014|79|76
127.8045|125.4002|127|124
106.0921|104.8796|105|104
151.5683|148.3245|150|148
121.2332|116.3521|120|116
123.2887|115.1104|123|114

Moritz

11

On 09/05/17 15:03, Moritz Lennert wrote:

On 09/05/17 14:37, Veronica Andreo wrote:

Hello Pierre,

Thanks for this new add-on! Comes on time for me :slight_smile:

I'm testing it and I have observed something odd.
I'm querying integer maps but v.what.rast.multi gives me float values. I
run v.what.rast and I get the proper integer values. Does it have
anything to do with what Paulo just pointed out?

The module just loops over a series of v.what.rast calls, so results
should not be different. If any, Paulo's point reinforces this as the
'-i' flag (i.e.interpolate nearest points) is never used...

Sorry, I take that back: the -i flag is always set as what is passed on to v.what.rast is 'flags' and without the '-i' flag set still is non-null (it contains "{'i': False}") and so

'if (interp_flag->answer)'

in v.what.rast/main.c returns true.

So, yes the issue is linked to Paulo's remark.

Moritz

12

On 09/05/17 15:13, Moritz Lennert wrote:

On 09/05/17 15:03, Moritz Lennert wrote:

On 09/05/17 14:37, Veronica Andreo wrote:

Hello Pierre,

Thanks for this new add-on! Comes on time for me :slight_smile:

I'm testing it and I have observed something odd.
I'm querying integer maps but v.what.rast.multi gives me float values. I
run v.what.rast and I get the proper integer values. Does it have
anything to do with what Paulo just pointed out?

The module just loops over a series of v.what.rast calls, so results
should not be different. If any, Paulo's point reinforces this as the
'-i' flag (i.e.interpolate nearest points) is never used...

Sorry, I take that back: the -i flag is always set as what is passed on
to v.what.rast is 'flags' and without the '-i' flag set still is
non-null (it contains "{'i': False}") and so

'if (interp_flag->answer)'

in v.what.rast/main.c returns true.

So, yes the issue is linked to Paulo's remark.

Fixed in r71072.

But

v.what.rast.multi map=test raster=elev_srtm_30m,elev_ned_30m,srtm,ned columns=srtm_float_nofl,ned_float_nofl,srtm_int_nofl,ned_int_nofl

v.what.rast.multi -i map=test raster=elev_srtm_30m,elev_ned_30m,srtm,ned columns=srtm_float_fl,ned_float_fl,srtm_int_fl,ned_int_fl

cat|srtm_float_nofl|ned_float_nofl|srtm_int_nofl|ned_int_nofl|srtm_float_fl|ned_float_fl|srtm_int_fl|ned_int_fl
1|88.40672|84.94218|88|84|88.74082|85.08109|88|84
2|109.1437|98.23732|109|98|108.8838|98.40421|108|98
3|121.3047|117.567|121|117|121.5324|117.8318|121|117
4|142.1468|131.73|142|131|142.0981|131.7365|141|131
5|121.9686|122.3212|121|122|122.9578|123.2583|122|122
6|80.502|82.1487|80|82|81.29526|82.14999|80|81

So, integer remains integer...

Moritz

13

Now it works! Thanks a lot for such a quick fix :slight_smile:

best,

Vero

···

2017-05-09 15:25 GMT+02:00 Moritz Lennert <mlennert@club.worldonline.be>:

On 09/05/17 15:13, Moritz Lennert wrote:

On 09/05/17 15:03, Moritz Lennert wrote:

On 09/05/17 14:37, Veronica Andreo wrote:

Hello Pierre,

Thanks for this new add-on! Comes on time for me :slight_smile:

I’m testing it and I have observed something odd.
I’m querying integer maps but v.what.rast.multi gives me float values. I
run v.what.rast and I get the proper integer values. Does it have
anything to do with what Paulo just pointed out?

The module just loops over a series of v.what.rast calls, so results
should not be different. If any, Paulo’s point reinforces this as the
‘-i’ flag (i.e.interpolate nearest points) is never used…

Sorry, I take that back: the -i flag is always set as what is passed on
to v.what.rast is ‘flags’ and without the ‘-i’ flag set still is
non-null (it contains “{‘i’: False}”) and so

‘if (interp_flag->answer)’

in v.what.rast/main.c returns true.

So, yes the issue is linked to Paulo’s remark.

Fixed in r71072.

But

v.what.rast.multi map=test raster=elev_srtm_30m,elev_ned_30m,srtm,ned columns=srtm_float_nofl,ned_float_nofl,srtm_int_nofl,ned_int_nofl

v.what.rast.multi -i map=test raster=elev_srtm_30m,elev_ned_30m,srtm,ned columns=srtm_float_fl,ned_float_fl,srtm_int_fl,ned_int_fl

cat|srtm_float_nofl|ned_float_nofl|srtm_int_nofl|ned_int_nofl|srtm_float_fl|ned_float_fl|srtm_int_fl|ned_int_fl
1|88.40672|84.94218|88|84|88.74082|85.08109|88|84
2|109.1437|98.23732|109|98|108.8838|98.40421|108|98
3|121.3047|117.567|121|117|121.5324|117.8318|121|117
4|142.1468|131.73|142|131|142.0981|131.7365|141|131
5|121.9686|122.3212|121|122|122.9578|123.2583|122|122
6|80.502|82.1487|80|82|81.29526|82.14999|80|81

So, integer remains integer…

Moritz

14

Thanks Luca, that would be a good idea indeed!

Any pointers to implement this? I’m unfamiliar with parallel processing in Pygrass.

Cheers,

P

···

On 9 May 2017 at 18:36, Luca Delucchi <lucadeluge@gmail.com> wrote:

On 8 May 2017 at 07:16, Pierre Roudier <pierre.roudier@gmail.com> wrote:

Hi all,

Hi,

FYI I just submitted my (first!) GRASS add-on, called v.what.rast.multi [0].

It is a super simple Python wrapper around v.what.rast, and allows to query
a suite of rasters in one go:

thanks, it is useful
to improve a little bit, you add multiprocessing to the module, for
example a process for each raster

Cheers,

Pierre

–
ciao
Luca

www.lucadelu.org

15

Hi Paulo,

fl is used to store flags passed to the command.

There was a typo in my code, and Moritz was kind enough to commit a corrected version of the add-on (thanks Moritz!),

Would be more than happy to merge both addons, they do look similar enough to be merged.

Cheers,

P

···

On 9 May 2017 at 19:30, Paulo van Breugel <p.vanbreugel@gmail.com> wrote:

Hi Pierre,

I have one question about the code. In lines 126-130 you create an object ‘fl’, which you subsequently do not seem to use. Perhaps in line 150 it should be flags=fl ?

Something else, last year I wrote an addon r.what.rastlabel (https://github.com/ecodiv/GRASS-scripts/tree/master/v.what.rastlabel) which can be used to (multiple) raster values and labels. Optionally, it can also upload raster values only, like your addon (that part uses the same approach you use). I have not yet added it to the grass addon repository. I might do that later, at which point we can also see if it makes sense to merge the two.

Cheers,

Paulo

On 5/9/17 8:36 AM, Luca Delucchi wrote:

On 8 May 2017 at 07:16, Pierre Roudier <pierre.roudier@gmail.com> wrote:

Hi all,

Hi,

FYI I just submitted my (first!) GRASS add-on, called v.what.rast.multi [0].

It is a super simple Python wrapper around v.what.rast, and allows to query
a suite of rasters in one go:

thanks, it is useful
to improve a little bit, you add multiprocessing to the module, for
example a process for each raster

Interesting, could help to speed up with large point data layers.

Cheers,

Pierre

16

On 10/05/17 23:49, Pierre Roudier wrote:

Thanks Luca, that would be a good idea indeed!

Any pointers to implement this? I'm unfamiliar with parallel processing
in Pygrass.

You can look at i.pansharpen for a simple example:

https://trac.osgeo.org/grass/browser/grass/branches/releasebranch_7_2/scripts/i.pansharpen/i.pansharpen.py#L151

or for a bit more sophisticated handling using PyGRASS:

https://grass.osgeo.org/grass72/manuals/libpython/pygrass.modules.interface.html#pygrass.modules.interface.module.ParallelModuleQueue

Other examples exist (cf i.segment.uspo for example)

Moritz