[GRASS5] v.in.shape missing some polygons

[Gualter Barbas Baptista]

Your solution ("hacking" the file in dig_att) worked perfectly! After 
two days trying to figure out a solution to this, it's really good to 
see all those polygons drawed.

This bug should be on the top priority for fixing ;)

Thanks,

Gualter

David D Gray wrote:

> Gualter Barbas Baptista wrote:
>
>> Is there some workaround for this (like exporting to some other 
>> format with Arcview) while it's not fixed?
>>
>> Thanks,
>>
>> Gualter
>>
>
>
> Can you get a script to export as e00? That should have the properly 
> deconstructed linework, and attributes with topology already built, so 
> it is then, if all else is OK, a direct import into GRASS. Similarly 
> for DLG (there never used to be a DLG export for GRASS, but it's a 
> while since I looked), or maybe SDTS.
>
> Otherwise, there are some tools, like XTools, that can export the 
> `centroids' as a point theme. These are a set of representative 
> interior points, one for each polygon, not true centroids in the 
> geometric sense, so can be used to carry the attributes of the 
> associated polygons.
>
> If you include the X and Y readings in the theme database, then that 
> can be converted to a text file easily and you then have the data you 
> need.
>
> This next bit is a bit `hacky', but I occasionally use it myself for 
> various reasons:
>
> 1) Use something like `awk' or `sed' to morph the lines of text in the 
> text file created above so each line has the following fields, in this 
> order with spaces separating:
>
> A <X-coord> <Y-coord> <your chosen numeric attribute>
>
> Note the `A' is literal and *must* be uppercase.
>
> 2) Drop this manually into the dig_att directory as a file with the 
> name of the target polygon coverage. This will probably replace the 
> existing file (which you might want to back up).
>
> 3) Rebuild the map with `v.support option=build'.
>
> You can carry out the above three stages with a sites_list file as 
> well, if you import the centroids coverage with s.in.shape. But some 
> people have reported this gives errors as well, on some platforms.
>
> David
>
>
>> David D Gray wrote:
>>
>>> Gualter Barbas Baptista wrote:
>>>
>>>> When I import shapefiles using v.in.shape almost everything goes 
>>>> ok, except for some polygons, that show up the lines, but have no 
>>>> values, which means that when I convert the vector file to raster 
>>>> there is nothing. I tried changing the colinearity tolerance and 
>>>> the snap distance, but the result is the same.
>>>> I tried exporting one of these images back as a E00 and the 
>>>> polygons that didn't show up had a value of zero. I changed 
>>>> manually the values to 1 and re-exported to shapefile, imported in 
>>>> GRASS, etc. and I got the same result.
>>>>
>>>> Is this some known bug or am I doing something wrong?
>>>>
>>>> Thanks,
>>>>
>>>> Gualter
>>>>
>>>
>>> Hi
>>>
>>> It is a known bug. It happens when a polygon is imported after all 
>>> the surounding polygons have been imported. This was originally a 
>>> `feature' to try and get round the annoying frequency with which (at 
>>> least older versions of) ArcView generated multiple copies of the 
>>> same polygon, usually simple island polygons. Unfortunately it had 
>>> this side-effect for some cell-like polygons, ie those with many 
>>> neighbours.
>>>
>>> The next release of v.in.shape should be free of this.
>>>
>>> David
>>>
>>>
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>>
>>
>>
>>
>>
>>
>>
>
>
>
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