[GRASSLIST:5550] Re: v.mkgrid extract grid sections

[Radim Blazek]

For me it works.
v.mkgrid map=pok grid=3,2 position=region
v.extract input=pok output=pok2 type=area list=4
...
Number of boundaries:   8
Number of centroids :   1
...

Radim

Dylan Beaudette wrote:
> Radim,
> 
> Thanks for the idea... but doing v.extract type=area leaves me with only the 
> centroids for each grid cell...
> 
> is there anyway to convert a set of line segments into a polygon?
> 
> thanks!
> 
> Dylan
> 
> On Thursday 27 January 2005 12:14 am, Radim Blazek wrote:
> 
>>Use v.extract type=area
>>
>>Radim
>>
>>Dylan Beaudette wrote:
>>
>>>On Wednesday 26 January 2005 06:09 pm, Hamish wrote:
>>>
>>>>>I have used v.mkgrid (GRASS6-CVS) in the past to make vector grids,
>>>>>and all  has been well.
>>>>
>>>>..
>>>>
>>>>
>>>>>However, this morning I tried to extract a single square from the
>>>>>output from  v.mkgrid, and was only able to get either a single
>>>>>centroid (almost correct),  or the entire boundary (not good). Since
>>>>>the boundaries do not have CATs,  there is no way for me to extract a
>>>>>single boundary...
>>>>
>>>>..
>>>>
>>>>
>>>>>Any ideas?
>>>>
>>>>what about
>>>>
>>>> v.category type=boundary option=add
>>>>
>>>>to add category numbers to the boundaries?
>>>
>>>Thanks! ... this gives the boundaries CATs... but for some reason, each
>>>grid square is made up of about 8 line segments (3 for top and bottom
>>>lines, 1 for each vertical line)...
>>>
>>>My hope is that i can make each grid "cell" into a discreet polygon, that
>>>can be used to set the region -- i.e. so that i can accurately subsample
>>>a larger map.
>>>
>>>thanks!
> 
>