[Mapserver-users] RE: Rasterization help, TIF->SHP

[Simpson, Andrew]

http://www.imagemagick.org/ has api's that allow one to get pixel values,
which can then be used to create vectors fairly easily if the raster's
colors and shapes are not too complex...



-----Original Message-----
From: Paul Dymecki [mailto:millardymecki at sympatico.ca]
Sent: Tuesday, June 24, 2003 7:10 AM
To: David Monterroso Cabello; Thorsten Fischer
Cc: mapserver-users at lists.gis.umn.edu
Subject: Re: [Mapserver-users] Rasterization help, TIF->SHP


Not sure if you've checked out mapscan for windows. It does vectorization of
Gif images though i don't know if you could automate it ,
Paul

----- Original Message -----
From: "David Monterroso Cabello" <pyro-x at ixine.com>
To: "Thorsten Fischer" <thfischer at mapmedia.de>
Cc: <mapserver-users at lists.gis.umn.edu>
Sent: Tuesday, June 24, 2003 5:39 AM
Subject: Re: [Mapserver-users] Rasterization help, TIF->SHP


> Thorsten Fischer wrote:
>
> >On Mon, 2003-06-23 at 22:36, David Monterroso Cabello wrote:
> >
> >
> >>Ed McNierney wrote:
> >>
> >>
> >>
> >>>I think you're mixing a few apples and oranges here.
> >>>
> >>>"Rasterization" is the process of converting vector data to raster
data,
> >>>
> >>>
> >>>
> >>Umm, i'm also interested in "the other way", i mean vectorization of
> >>raster data. I've some raster images that are georeferenced and are
> >>formed only from lines over a white background. Do you know about any
> >>tool for the unix world that convert that into vector data (shapefile or
> >>anything) automatically?, perhaps grass??.
> >>
> >>
> >
> >There is no such thing as a tool where you can just click a button and
> >it converts raster data into vector data. As Ed said, this is a highly
> >specialized task. It has not been generically automated yet, and as far
> >as i can see it is more than unlikely that it ever will be.
> >
> >
> Well, i understand there is no "one click" application that will deliver
> a perfect shape, but what im looking for is an application that with the
> correct  configuration, and parameters  can be launched  from a script,
> and then convert the raster into vector data automatically, i don't know
> if it is impossible but as my data is always the same i think i still
> have a chance to automate it.
>
> >'Simple' black lines on a white background sounds easy, but it is not.
> >Imagine your program finds lines in your images and identifies an
> >intersection of lines. How is the software supposed to know which parts
> >of the intersection belong to which line? In every case you will have to
> >do some manual work afterwards, and in this case you usually can just
> >load the map into some GIS and digitize the whole thing by hand.
> >
> >
>     Well, i know sometimes there will be some errors whithin the
> process, but i think i can live with that, i need it only for graphic
> representation, so it doesn't have to be perfect.
>
> >As I usually say before the start of seminars and workshops: i got a
> >computer scientist background, not a cartographic or geographic one. So
> >please correct me if I said something terribly wrong :)
> >
> >
>     Well, i'm in the same situation, but my knowledge about GIS is much
> much much smaller i  think ;). I  will try GRASS, what i fear is that
> perhaps i can't automate the whole process, but we'll see...
>
> >
> >hth,
> >
> >thorsten
> >
> >
> >
> David.
>
>
> _______________________________________________
> Mapserver-users mailing list
> Mapserver-users at lists.gis.umn.edu
> http://lists.gis.umn.edu/mailman/listinfo/mapserver-users

_______________________________________________
Mapserver-users mailing list
Mapserver-users at lists.gis.umn.edu
http://lists.gis.umn.edu/mailman/listinfo/mapserver-users