[GRASS-user] Problem with v.edit delete tool

Hi List,

This is probably more due to my lack of understanding of how v.edit works. But here it goes.

I have a polygon vector layer where some of the polygons have a ‘No data’ label. I’d like to delete those polygons so I ran the command, with the following output:

v.edit map=teste@isna tool=delete where=“label like ‘%no data%’”
Selecting features…
207 of 7200 features selected from vector map teste@isna
207 features deleted
Building topology for vector map teste@isna
Registering primitives…
6993 primitives registered
29546 vertices registered
Building areas…
2195 areas built
264 isles built
Attaching islands…
Attaching centroids…
Number of nodes: 3086
Number of primitives: 6993
Number of points: 0
Number of lines: 0
Number of boundaries: 5017
Number of centroids: 1976
Number of areas: 2195
Number of isles: 264
v.edit complete.

After that, the offending polygons where deleted however, their boundaries are still present. That is, when I load the vector in the map display, I still see the boundaries in some polygons, even though the area is not filled. Is this the intended behavior? I tried using the areadel tool but then the whong polygon was deleted. I’m guessing the shared boundary of a valid polygon was removed and his caused problems.

Attached is a sample of what I’m seeing after v.edit delete

Thanks

Daneil

Inline image 1

Oops, forgot to mention I’m using Grass 7.0.4 from OSGeo4Win 64 bits

(attachments)

image.png

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On Wed, Aug 31, 2016 at 11:32 AM, Daniel Victoria <daniel.victoria@gmail.com> wrote:

Hi List,

This is probably more due to my lack of understanding of how v.edit works. But here it goes.

I have a polygon vector layer where some of the polygons have a ‘No data’ label. I’d like to delete those polygons so I ran the command, with the following output:

v.edit map=teste@isna tool=delete where=“label like ‘%no data%’”
Selecting features…
207 of 7200 features selected from vector map teste@isna
207 features deleted
Building topology for vector map teste@isna
Registering primitives…
6993 primitives registered
29546 vertices registered
Building areas…
2195 areas built
264 isles built
Attaching islands…
Attaching centroids…
Number of nodes: 3086
Number of primitives: 6993
Number of points: 0
Number of lines: 0
Number of boundaries: 5017
Number of centroids: 1976
Number of areas: 2195
Number of isles: 264
v.edit complete.

After that, the offending polygons where deleted however, their boundaries are still present. That is, when I load the vector in the map display, I still see the boundaries in some polygons, even though the area is not filled. Is this the intended behavior? I tried using the areadel tool but then the whong polygon was deleted. I’m guessing the shared boundary of a valid polygon was removed and his caused problems.

Attached is a sample of what I’m seeing after v.edit delete

Thanks

Daneil

Inline image 1

On 31/08/16 16:32, Daniel Victoria wrote:

Hi List,

This is probably more due to my lack of understanding of how v.edit
works. But here it goes.

I have a polygon vector layer where some of the polygons have a 'No
data' label. I'd like to delete those polygons so I ran the command,
with the following output:

v.edit map=teste@isna tool=delete where="label like '%no data%'"
Selecting features...
207 of 7200 features selected from vector map <teste@isna>
207 features deleted
Building topology for vector map <teste@isna>...
Registering primitives...
6993 primitives registered
29546 vertices registered
Building areas...
2195 areas built
264 isles built
Attaching islands...
Attaching centroids...
Number of nodes: 3086
Number of primitives: 6993
Number of points: 0
Number of lines: 0
Number of boundaries: 5017
Number of centroids: 1976
Number of areas: 2195
Number of isles: 264
v.edit complete.

After that, the offending polygons where deleted however, their
boundaries are still present. That is, when I load the vector in the map
display, I still see the boundaries in some polygons, even though the
area is not filled. Is this the intended behavior? I tried using the
areadel tool but then the whong polygon was deleted. I'm guessing the
shared boundary of a valid polygon was removed and his caused problems.

Attached is a sample of what I'm seeing after v.edit delete

Attributes of areas are linked to the centroid of the area. So the features you select through your query are these centroids, not the boundaries.

It would probably be nice to have a type=area option in v.edit.

To get the same result, you could use v.extract -r type=area.

Moritz

Thanks Moritz,

v.extract did the job. The only downside is that I need to keep creating temporary layers since I’ll have to do a series of edits. But no problem. It can be done.

Cheers

Daniel

···

On Wed, Aug 31, 2016 at 11:40 AM, Moritz Lennert <mlennert@club.worldonline.be> wrote:

On 31/08/16 16:32, Daniel Victoria wrote:

Hi List,

This is probably more due to my lack of understanding of how v.edit
works. But here it goes.

I have a polygon vector layer where some of the polygons have a ‘No
data’ label. I’d like to delete those polygons so I ran the command,
with the following output:

v.edit map=teste@isna tool=delete where=“label like ‘%no data%’”
Selecting features…
207 of 7200 features selected from vector map teste@isna
207 features deleted
Building topology for vector map teste@isna
Registering primitives…
6993 primitives registered
29546 vertices registered
Building areas…
2195 areas built
264 isles built
Attaching islands…
Attaching centroids…
Number of nodes: 3086
Number of primitives: 6993
Number of points: 0
Number of lines: 0
Number of boundaries: 5017
Number of centroids: 1976
Number of areas: 2195
Number of isles: 264
v.edit complete.

After that, the offending polygons where deleted however, their
boundaries are still present. That is, when I load the vector in the map
display, I still see the boundaries in some polygons, even though the
area is not filled. Is this the intended behavior? I tried using the
areadel tool but then the whong polygon was deleted. I’m guessing the
shared boundary of a valid polygon was removed and his caused problems.

Attached is a sample of what I’m seeing after v.edit delete

Attributes of areas are linked to the centroid of the area. So the features you select through your query are these centroids, not the boundaries.

It would probably be nice to have a type=area option in v.edit.

To get the same result, you could use v.extract -r type=area.

Moritz