[Qgis-developer] Re: [Qgis-user] Error in Georeferencer tool

[Agustin Lobo]

Unfortunately this is not the case with ED50 UTM31N: the resulting layer has the
correct CRS, but it is shifted. The points appear where they have to
be, but the raster layer
is shifted.
We'll try with points set on google mercator.
Thanks

2011/11/28  <dennis at dmlinton.net>:
> Hi, Agus;
>
> You set your desired CRS in the Georeferencing properties.  What I am
> saying is that this setting seems to be ignored and, in place of the
> specified CRS, some strange unknown custom CRS is substituted.  By going
> to the layer properties for the georeferenced layer (after it has been
> added to your project) and resetting the CRS to the correct one, the
> georeferenced layer then displays properly.  This is my experience
> anyhow - particularly using Google or OSM (both have Google Mercator CRS)
> maps as reference.
>
> Best regards,
>    Dennis
>
>> I was suspecting something like this too. But the question is that the CRS
>> of the input image should be, by definition, unknown. In case the input
>> image has a CRS, this CRS should be just ignored. Instead, the plugin
>> actually prompts the user about the CRS of the input image. And I do not
>> find any way to set the input CRS to unknown or just arbitrary x,y
>> coordinates (while this is possible in Grass).
>>
>> Where you say:
>>
>> "Upon resetting the CRS specified in the layer properties to the correct
>> one, all was well"
>> do you refer to the input or to the output image?
>>
>> Agus
>>
>> 2011/11/27 Dennis M. Linton <dennis at dmlinton.net>
>>
>>> **
>>> I have observed this behaviour in QGIS 1.7.2 and found, upon reviewing
>>> the
>>> layer properties of the georectified layer, that the coordinate
>>> reference
>>> system being used was NOT the one specified in the Georeferencing
>>> plugin.
>>> Rather, the CRS was some unknown custom CRS.  Upon resetting the CRS
>>> specified in the layer properties to the correct one, all was well.
>>>
>>> Hope this helps.
>>>
>>> Best regards,
>>>     Dennis
>>>
>>> --
>>> Dennis M. Linton, P.Eng.
>>> Tel: +1 (613) 473-1015
>>> Cell: +1 (705) 312-1336
>>> Skype: thedmlinton
>>>
>>>
>>>
>>>
>>>   On Sun, 2011-11-27 at 22:10 +0100, Agustin Lobo wrote:
>>>
>>>
>>> Hi!
>>> We are using the Georeferencer tool and the resulting image is shifted,
>>> please see the screenshot
>>> here:https://sites.google.com/site/filestemp2/home/error_georef.jpg?attredirects=0
>>>
>>>
>>> We've tried polynomia of order 1 and 2 and Helmert, with very similar
>>> results.
>>>
>>> I think this is a bug, but I'm not sure we are not actually doing
>>> something wrong.
>>>
>>> Agus
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>>
>
>
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