[GRASS-user] How update vector layers?

GRASS GRASS user
1

Hi Vincent,
I’ve tried the following command:

v.patch -ae input=sugarcane,sugarcane_update output=sugarcane --o

it returns:
ERROR: Output vector map is used as input

I’m using the -e and -a flags and overwriting the old vector layer, but the message is the same.

I’m doing anything wrong?

Both vector maps have exactly the same columns and there aren’t identical attributes:

Cat (integer)
Cane_id(Integer)

thanks,
Thyberio

2

If you are sure category values don't overlap, then you can use the -a
flag. But in this case I would NOT give both arguments -a and -e;
i.e. given that the sugarcane map already has a related table, the
features from sugarcane_update will populate the table with new rows (it
is the reason why cat numbers, which tag geometrical features, should be
distinct from previous rows in the sugarcane table)...
Else you can try to create a new map :
v.patch -e in=sugarcane,sugarcane_update out=merge,

If you suspect duplicate objets (e.g. adjacent areas boundaries), don't
forget to run v.clean with the tool rmdupl.

Vincent.

Le samedi 07 mars 2009 à 16:03 -0300, Thybério Luna Freire a écrit :

Hi Vincent,
I've tried the following command:

v.patch -ae input=sugarcane,sugarcane_update output=sugarcane --o

it returns:
ERROR: Output vector map <sugarcane> is used as input

I'm using the -e and -a flags and overwriting the old vector layer,
but the message is the same.

I'm doing anything wrong?

Both vector maps have exactly the same columns and there aren't
identical attributes:

Cat (integer)
Cane_id(Integer)

thanks,
Thyberio
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3

On Sat, Mar 7, 2009 at 8:03 PM, Thybério Luna Freire <thyberio@gmail.com> wrote:

Hi Vincent,
I've tried the following command:

v.patch -ae input=sugarcane,sugarcane_update output=sugarcane --o

it returns:
ERROR: Output vector map <sugarcane> is used as input

You have to write the output to a new map name.

Markus

4

Having a look at the man page of the v.patch command, I was surprised by
a semantic ambiguity : saying v.patch "Create[s] a new vector map layer
by combining other vector map layers" sounds quite odd, shouldn't we
say :"Create a new vector map by combining other vector maps", given
that only layer 1 is supported ? well, maybe there is no confusion and
I misunderstand something ?

In the current french translation of wxpython GUI, there are several
confusions between these notions of maps and layers*, which IMHO should
be clearly distinguished if we want to show a coherent vector data
model.

Bye,
VB

__________
* I know I should keep working on translation files, but for the moment
I'm really over-loaded.

Le samedi 07 mars 2009 à 21:02 +0100, Markus Neteler a écrit :

On Sat, Mar 7, 2009 at 8:03 PM, Thybério Luna Freire <thyberio@gmail.com> wrote:
> Hi Vincent,
> I've tried the following command:
>
> v.patch -ae input=sugarcane,sugarcane_update output=sugarcane --o
>
> it returns:
> ERROR: Output vector map <sugarcane> is used as input

You have to write the output to a new map name.

Markus
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5

On Sat, Mar 7, 2009 at 9:21 PM, Vincent Bain <bain@toraval.fr> wrote:

Having a look at the man page of the v.patch command, I was surprised by
a semantic ambiguity : saying v.patch "Create[s] a new vector map layer
by combining other vector map layers" sounds quite odd, shouldn't we
say :"Create a new vector map by combining other vector maps", given
that only layer 1 is supported ?

Yes, fixed everywhere.

well, maybe there is no confusion and
I misunderstand something ?

No, it was confusing.

In the current french translation of wxpython GUI, there are several
confusions between these notions of maps and layers*, which IMHO should
be clearly distinguished if we want to show a coherent vector data
model.

Right - please point out these things as you come across them.

Markus