Hi,
After a vectorisation from a raster obtained by the r.los function, I get
polygon whom own some island inside them. I would like to remove this island?
Here :http://yjacolin.gloobe.org/problem.htm, three pictures :
1/ what I expect to
2/ What I get
I obtain the first picture by using sql resquest (display only value=1).
Do you know where the problem came from ?
Thanks to any tips ! It seems to me that I saw something about this in the
past in this list but ...
After a vectorisation from a raster obtained by the r.los function, I
get polygon whom own some island inside them. I would like to remove
this island? Here :http://yjacolin.gloobe.org/problem.htm, three
pictures :
1/ what I expect to
2/ What I get
I obtain the first picture by using sql resquest (display only
value=1).
After a vectorisation from a raster obtained by the r.los function, I
get polygon whom own some island inside them. I would like to remove
this island? Here :http://yjacolin.gloobe.org/problem.htm, three
pictures :
1/ what I expect to
2/ What I get
I obtain the first picture by using sql resquest (display only
value=1).
Hello,
Thanks for your help. I am wondering if my layer is correct! I try v.extract
-d input=visibilite output=visibilite_correct list=1-99999, nothing change !
Furthermore, if I choose to fill area by a "random fills colors for each cat
values", 'islanf' are emtpy. When I export by v.out.org and use -c options in
shapefile, qgis display the layer correctly.
If I query the raster layer just before vectorisation, I obtain a 'good'
answer for polygons (ie, cat value displayed) and for island I just obtain an
empty windows, but the boundary is selected in the screen...
Acutally I don't understand how polygons are managed in Grass. I thank that I
read such subject in the past in this list, but I am maybe wrong.
Y.
Le Jeudi 18 Mai 2006 11:35, Markus Neteler a écrit :
Hamish wrote:
>>After a vectorisation from a raster obtained by the r.los function, I
>>get polygon whom own some island inside them. I would like to remove
>>this island? Here :http://yjacolin.gloobe.org/problem.htm, three
>>pictures :
>> 1/ what I expect to
>> 2/ What I get
>>
>>I obtain the first picture by using sql resquest (display only
>>value=1).
>
>[url broken, it's .html]
>
>
>use v.extract list=1-99999 and/or v.extract -d
On Thu, 18 May 2006 22:19:57 +0200
Yves Jacolin <yjacolin@free.fr> wrote:
Hello,
Thanks for your help. I am wondering if my layer is correct! I try
v.extract -d input=visibilite output=visibilite_correct list=1-99999,
nothing change ! Furthermore, if I choose to fill area by a "random
fills colors for each cat values", 'islanf' are emtpy. When I export
by v.out.org and use -c options in shapefile, qgis display the layer
correctly.
If I query the raster layer just before vectorisation, I obtain a
'good' answer for polygons (ie, cat value displayed) and for island I
just obtain an empty windows, but the boundary is selected in the
screen... Acutally I don't understand how polygons are managed in
Grass. I thank that I read such subject in the past in this list, but
I am maybe wrong.
area = boundary (no category needed) + centroid
Area atrributes are "physically" assigned to a centroid.
Hope this helps.
Best,
Maciek
--------------------
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