Raster Image and Shapefile Alignment

[Richard Duivenvoorde]

Hi Bradley,

I managed to georeference some rasters I had using the free tools listed 
here:
http://www.forestpal.com/Help/georeference.html

Richard


Bradley Mclain wrote:
> How would you suggest I go about re-doing the georeferencing?
> 
> Brad
> 
> 
> 
> 
> 
>> From: Barend Köbben <kobben at itc.nl>
>> To: Bradley Mclain <bradleym06 at HOTMAIL.COM>
>> Subject: Re: [UMN_MAPSERVER-USERS] Raster Image and Shapefile Alignment
>> Date: Fri, 02 Feb 2007 09:19:33 +0100
>>
>> HI,
>>
>> The shapefile is in an Australian projection, and your raster has been
>> georeferenced to *something*, but there's no telling to what 
>> projection they
>> georef'd it, because there's no projection info in the raster file.
>>
>> In other words: someone told the raster "you fit in this place in the 
>> world,
>> between XY 1 and XY 2", but they didn't specify in what projection system
>> those XY's are. You would suppose to the same projection the vector is 
>> in,
>> and in that case, the fit will be OK as long as the projection of the 
>> shape
>> remains the same as it was when the raster was georef'd to it. But if one
>> changes that projection, or maybe only the Datum, as tends to happen
>> unexpectedly when you transfer files from one GIS to another, things will
>> misalign...
>>
>> To make matters worse, it can also just be a case of sloppy
>> georeferencing...
>>
>> Without knowing the rasterprojection, there's no solution, except 
>> re-doing
>> the georeferencing...
>>
>> On 02-02-2007 07:16, "Bradley Mclain" <bradleym06 at HOTMAIL.COM> wrote:
>>
>> > Umm I know very little about geodata so i'll simply attach the 
>> readouts from
>> > ogrinfo and gdalinfo so you can see for yourself cause i have no 
>> idea. :)
>> >
>> > If it helps any they are only out slightly. (as shown in attached
>> > screenshot)
>> >
>> > Bradley Mclain
>> >
>> >
>> >
>> >
>> >> From: "Gregor Mosheh" <gregor at hostgis.com>
>> >> Reply-To: support at hostgis.com
>> >> To: "Brad_Mclain" <bradleym06 at HOTMAIL.COM>
>> >> CC: mapserver-users at lists.umn.edu
>> >> Subject: Re: [UMN_MAPSERVER-USERS] Raster Image and Shapefile 
>> Alignment
>> >> Date: Thu, 1 Feb 2007 23:02:05 -0700 (MST)
>> >>
>> >>> Ok here is the sitution I have a raster image and shapefile data 
>> but the
>> >>> two do not line up correctly.
>> >>
>> >> Are you positive that they're both in the same projection? Or, do 
>> you know
>> >> the projection for each one? I've had so many annoyances in the 
>> past where
>> >> something was in "CA State Plane II" and then had to figure out 
>> which of
>> >> the five CA State Plane II projections it really was. :)
>> >>
>> >> If you know the projection for each, be sure to specify it in your 
>> mapfile
>> >> using a PROJECTION block in your LAYER block. You can probably get 
>> more
>> >> help on that once we know a bit more about the matter.
>> >>
>> >> Best of luck, Brad.
>> >>
>> >> -G
>> >>
>> >
>> > _________________________________________________________________
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> 
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