[GRASS5] do polylines share endpoints?

[Christopher Fonnesbeck]

On Apr 26, 2004, at 12:43 PM, Radim Blazek wrote:

>> I am trying to use v.select on a stream layer to select all stream
>> segments connected to a chosen segment, first using v.extract:
>>
>> v.extract list=96 input=streams output=foo
>>
>> then using v.select with "foo":
>>
>> v.select ainput=streams binput=foo output=bar
>>
>> This works fine for most segments, but many segments that are clearly
>> attached to other segments are considered by v.select to be 
>> unattached.
>> For example, in the screen shot I have attached to this message, the 
>> red
>> line shows the layer "bar" which by the method above should be that
>> segment *plus* the 2 segments to which it is clearly connected. 
>> Shouldnt
>> these three segments share an endpoint? If not, how is one supposed to
>> select neighbours?
>
> Check it in v.digit (Settings -> Symbology: node (1 line), node (2 
> lines) )
> If lines are not connected use v.clean tool=snap,break.

The lines seem to be connected (see attached -- green=2 lines, red=1 
line), yet the code above does not select the main stream segment using 
one of its branches (the longer upward-pointing segment in the attached 
image).

Thanks,
Chris
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--
Christopher J. Fonnesbeck ( c h r i s @ f o n n e s b e c k . o r g )
Georgia Cooperative Fish & Wildlife Research Unit, University of Georgia

"More and more of our imports come from overseas."
          George W. Bush, 25 September 2000
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--
Christopher J. Fonnesbeck ( c h r i s @ f o n n e s b e c k . o r g )
Georgia Cooperative Fish & Wildlife Research Unit, University of Georgia

"More and more of our imports come from overseas."
          George W. Bush, 25 September 2000
--
Putting http://wecanstopspam.org in your email helps it pass through 
overzealous spam filters.