[GRASS-user] Use of v.in.ascii in python with stdin
Hi, I want to create a point via python at a specific location using the v.in.ascii command. How can I also specify the colum names or how can a header be used in combination with the standard input. As it is only one single point I don't want to create a txt file containing the header and the info. I tried following in GRASS7: grass.write_command(v.in.ascii, overwrite=True, format=point, #flags=n, input=-, x=1, y=2, stdin=X,Y,Name\n 10:20:08E,53:25:27N,my_point_1, output=my_point, separator=,) ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Use of v.in.ascii in python with stdin
Hi Johannes,
On Mon, Jun 17, 2013 at 1:24 PM, Johannes Radinger
johannesradin...@gmail.com wrote:
I want to create a point via python at a specific location using the
v.in.ascii command. How can I also specify the colum names or how can a
header be used in combination with the standard input. As it is only one
single point I don't want to create a txt file containing the header and the
info. I tried following in GRASS7:
I think that some of your parameters are not correct...
{{{
from grass.pygrass.modules import Module
ASCII = cat,X,Y,Name
1,635828.3,223067.0,pub
2,643553.4,220711.5,pizzeria
COLS = 'cat int, x double precision, y double precision, name varchar(10)'
vina = Module('v.in.ascii', input='-', output='pnt__v_in_ascii',
format='point', separator=',', skip=1, x=2, y=3, cat=1,
columns=COLS, stdin_=ASCII, overwrite=True,
finish_=True)
}}}
Mostly with the same parameters you can run grass.write_command.
But If you are looking for a tool to play and experiment I highly
suggest pygrass:
{{{
from grass.pygrass.vector import VectorTopo
from grass.pygrass.geometry import Point
new = VectorTopo('mynewvect')
COLS = [(u'cat', 'INTEGER PRIMARY KEY'), (u'name', 'VAR CHAR')]
new.open('w', tab_cols=COLS)
new.write(Point(635828.3, 223067.0), ('pub', ))
new.write(Point(643553.4, 220711.5), ('restaurant', ))
new.close()
new.open('r')
new.cat(1).attrs['name'] # return: pub
new.close()
}}}
If you are interested please have a look of the ipython notebook:
https://github.com/zarch/workshop-pygrass
you have just to clone, and from a running session of grass enter in
the directory and launch:
ipython notebook
to have a briefly introduction to the library.
Have fun!
Pietro
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Re: [GRASS-user] Use of v.in.ascii in python with stdin
Hi,
On Mon, Jun 17, 2013 at 3:39 PM, Pietro peter.z...@gmail.com wrote:
Hi Johannes,
On Mon, Jun 17, 2013 at 1:24 PM, Johannes Radinger
johannesradin...@gmail.com wrote:
I want to create a point via python at a specific location using the
v.in.ascii command. How can I also specify the colum names or how can a
header be used in combination with the standard input. As it is only one
single point I don't want to create a txt file containing the header and
the
info. I tried following in GRASS7:
I think that some of your parameters are not correct...
{{{
from grass.pygrass.modules import Module
ASCII = cat,X,Y,Name
1,635828.3,223067.0,pub
2,643553.4,220711.5,pizzeria
COLS = 'cat int, x double precision, y double precision, name varchar(10)'
vina = Module('v.in.ascii', input='-', output='pnt__v_in_ascii',
format='point', separator=',', skip=1, x=2, y=3,
cat=1,
columns=COLS, stdin_=ASCII, overwrite=True,
finish_=True)
}}}
I thought I found the problem by seeing the difference between the
parameter: stdin_ and
stdin. However here the result with _:
grass.write_command(v.in.ascii,
overwrite=True,
format=point,
#flags=n,
input=-,
cat=1,
x=2,
y=3,
stdin_=ascii,
columns=cols,
output=mypoint,
separator=,)
Traceback (most recent call last):
File input, line 12, in module
File /usr/local/grass-7.0.svn/etc/python/grass/script/core.py, line
331, in write_command
stdin = kwargs['stdin']
KeyError: 'stdin'
So I tried without:
ascii = cat,X,Y,Name
1,10:20:08E,53:25:27N,mypoint
cols = 'cat int, x varchar(10), y varchar(10), name varchar(10)'
grass.write_command(v.in.ascii,
overwrite=True,
format=point,
#flags=n,
input=-,
cat=1,
x=2,
y=3,
stdin=ascii,
columns=cols,
output=mypoint,
separator=,)
which at least executes but gives me following error:
GRASS_INFO_ERROR(13239,2): Unparsable longitude value in column num 2: X
Everything seems to be similar to your example except for the fact that I
am using lat/long values instead of projected double precision X
Y coordinates.
Mostly with the same parameters you can run grass.write_command.
But If you are looking for a tool to play and experiment I highly
suggest pygrass:
{{{
from grass.pygrass.vector import VectorTopo
from grass.pygrass.geometry import Point
new = VectorTopo('mynewvect')
COLS = [(u'cat', 'INTEGER PRIMARY KEY'), (u'name', 'VAR CHAR')]
new.open('w', tab_cols=COLS)
new.write(Point(635828.3, 223067.0), ('pub', ))
new.write(Point(643553.4, 220711.5), ('restaurant', ))
new.close()
new.open('r')
new.cat(1).attrs['name'] # return: pub
new.close()
}}}
If you are interested please have a look of the ipython notebook:
https://github.com/zarch/workshop-pygrass
you have just to clone, and from a running session of grass enter in
the directory and launch:
ipython notebook
to have a briefly introduction to the library.
Have fun!
Pietro
___
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grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Use of v.in.ascii in python with stdin
So I tried without: ascii = cat,X,Y,Name 1,10:20:08E,53:25:27N,mypoint cols = 'cat int, x varchar(10), y varchar(10), name varchar(10)' grass.write_command(v.in.ascii, overwrite=True, format=point, #flags=n, input=-, cat=1, x=2, y=3, stdin=ascii, columns=cols, output=mypoint, separator=,) which at least executes but gives me following error: GRASS_INFO_ERROR(13239,2): Unparsable longitude value in column num 2: X you need skip=1 or put a # in front of the first line, it's trying to parse the header line. style: since the stdin= option is a virtual one for grass.write_command(), consider putting it last. Hamish ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
