[GRASS-user] problems with v.edit - merge

I can’t figure out how to solve a problem with a line feature shapefile I have. It has been wrongly created as 81 single lines touching each other with their vertexes. I need to merge the lines into a unique line. I’ve tried with v.edit and the merge tool, two times. First time it gave me 32 lines, the second I receive the following result:

1 of 4 features selected from vector map costa@PERMANENT

Only 1 lines found, at least two needed

-1 lines merged
Building topology …
Registering lines:
4 primitives registered
Building areas:

0 areas built
0 isles built
Attaching islands:
Attaching centroids:

Topology was built.
Number of nodes : 5
Number of primitives: 4
Number of points : 0
Number of lines : 4
Number of boundaries: 0
Number of centroids : 0
Number of areas : 0
Number of isles : 0

v.edit complete.

I can’t understand what it means: it says it selected 4 lines but then just 1 line has been found. the post build report lists 4 lines… I’m a bit confused.
I’ve manually merged all the categories too with v.digit, but nothing seems to change (neither better nor worst!).

What am I doing wrong? What’s the best method to achieve my task?

Thanks,
Giovanni

Ciao,

2008/1/12, G. Allegri <giohappy@gmail.com>:

I can't figure out how to solve a problem with a line feature shapefile I
have. It has been wrongly created as 81 single lines touching each other
with their vertexes. I need to merge the lines into a unique line. I've
tried with v.edit and the merge tool, two times. First time it gave me 32
lines, the second I receive the following result:

1 of 4 features selected from vector map <costa@PERMANENT>

Only 1 lines found, at least two needed

[snip]

I can't understand what it means: it says it selected 4 lines but then just
1 line has been found. the post build report lists 4 lines... I'm a bit
confused.

it means that your vector map contains 4 features (in this case
lines), but you selected only one line for merging (you have to select
at least two lines to enable merging tool).

which parameters you used for v.edit?

Martin

--
Martin Landa <landa.martin@gmail.com> * http://gama.fsv.cvut.cz/~landa *

Ok I found out the problem meanwhile you were answering. I had 4 lines but three of them where very weird: 2 points, vertex to the same vertex → a point, but stored as a line. I couldn’t see it, beacuse it was superimposed on the major, single line.
I think it was a problem with the original shapefile…

Thanks anyway Martin.

2008/1/12, Martin Landa <landa.martin@gmail.com >:

Ciao,

2008/1/12, G. Allegri <giohappy@gmail.com >:

I can’t figure out how to solve a problem with a line feature shapefile I
have. It has been wrongly created as 81 single lines touching each other
with their vertexes. I need to merge the lines into a unique line. I’ve
tried with v.edit and the merge tool, two times. First time it gave me 32
lines, the second I receive the following result:

1 of 4 features selected from vector map costa@PERMANENT

Only 1 lines found, at least two needed

[snip]

I can’t understand what it means: it says it selected 4 lines but then just
1 line has been found. the post build report lists 4 lines… I’m a bit
confused.

it means that your vector map contains 4 features (in this case
lines), but you selected only one line for merging (you have to select
at least two lines to enable merging tool).

which parameters you used for v.edit?

Martin


Martin Landa <landa.martin@gmail.com> * http://gama.fsv.cvut.cz/~landa *

G. Allegri wrote:

I can't figure out how to solve a problem with a line feature
shapefile I have. It has been wrongly created as 81 single lines
touching each other with their vertexes. I need to merge the lines
into a unique line.
I've tried with v.edit and the merge tool, two times.

Once the number of errors is small, maybe v.digit helps too.

Hamish

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