[gdal-dev] Converting from Lambert (LCC) to latlong/mercator

[Joaquim Luis]

Brian Murray wrote:
> I know. I left that on there in the mean time while I figured out the
> translations. It wasn't even bending the map at all before. The
> software just sees the image as a blob of data, that you have to tell
> it how to transform, so it really didn't care that the map had a
> legend left on it. In my last post, I describe how I finally got it to
> work. :)

Good for you,

... but are you sure it worked? I mean, are you sure that it is correctly
referenced?
At half way of the description I just quit following it (sorry, too complicated for me).

Joaquim Luis

> 
> On Sun, Feb 22, 2009 at 12:59 PM, Joaquim Luis <jluis at ualg.pt> wrote:
>>
>> Brian,
>>
>> The left side of your image contains a ... legend, so it's not part of the
>> map. How can any program guess what is legend and where the map starts?
>>
>> Joaquim Luis
>>
>>> I am still battleing this conversion. I was just informed, via IRC,
>>> that gdal won't overwrite existing files, so I may have been making a
>>> difference, but not knowing it. In any case, I tossed together a
>>> simple script, that thus far, does nothing...
>>>
>>> #!/bin/sh
>>>
>>> rm -rf nn.tif n-merc.tif
>>>
>>> echo '*** Translate ***'
>>> gdal_translate n.tif nn.tif -of gtiff -CO TFW=YES -mo
>>> TIFFTAG_XRESOLUTION= -mo TIFFTAG_YRESOLUTION= -a_ullr -115d0 56d0
>>> -105d0 54d0 -a_srs "+proj=lcc +lat_0=54 +lon_0=-115 +lat_1=49.33
>>> +lat_2=54.66 +x_0=0 +y_0=0 +datum=NAD27 +ellps=clrk80"
>>>
>>> echo '***   Warp    ***'
>>> gdalwarp -t_srs "+proj=merc +datum=WGS84" nn.tif n-merc.tif
>>>
>>> open n-merc.tif
>>>
>>>
>>> I have also posted the source file I am working with, albeit scaled
>>> down and converted so its not 140mb.
>>>
>>> http://game-sat.com/~brian/north.png
>>>
>>> What concerns me is what gdalinfo gives me for the intermediate step,
>>> as the georeferenced coordinates are dead wrong. If I remove the a_srs
>>> to assign it as being an actual lambert conformal projection, it
>>> doesn't even have the georeferenced options, just the first ones.
>>>
>>> $ gdalinfo nn.tif
>>> Driver: GTiff/GeoTIFF
>>> Files: nn.tif
>>> Size is 11696, 4208
>>> Coordinate System is:
>>> PROJCS["unnamed",
>>>    GEOGCS["NAD27",
>>>        DATUM["North_American_Datum_1927",
>>>            SPHEROID["Clarke 1866",6378206.4,294.9786982139006,
>>>                AUTHORITY["EPSG","7008"]],
>>>            AUTHORITY["EPSG","6267"]],
>>>        PRIMEM["Greenwich",0],
>>>        UNIT["degree",0.0174532925199433],
>>>        AUTHORITY["EPSG","4267"]],
>>>    PROJECTION["Lambert_Conformal_Conic_2SP"],
>>>    PARAMETER["standard_parallel_1",49.33],
>>>    PARAMETER["standard_parallel_2",54.66],
>>>    PARAMETER["latitude_of_origin",54],
>>>    PARAMETER["central_meridian",-115],
>>>    PARAMETER["false_easting",0],
>>>    PARAMETER["false_northing",0],
>>>    UNIT["metre",1,
>>>        AUTHORITY["EPSG","9001"]]]
>>> Origin = (-115.000000000000000,56.000000000000000)
>>> Pixel Size = (0.000854993160055,-0.000475285171103)
>>> Metadata:
>>>  AREA_OR_POINT=Area
>>>  TIFFTAG_SOFTWARE=Adobe Photoshop CS3 Macintosh
>>>  TIFFTAG_DATETIME=2009:02:21 16:15:49
>>>  TIFFTAG_XRESOLUTION=0
>>>  TIFFTAG_YRESOLUTION=0
>>>  TIFFTAG_RESOLUTIONUNIT=2 (pixels/inch)
>>> Image Structure Metadata:
>>>  INTERLEAVE=PIXEL
>>> Corner Coordinates:
>>> Upper Left  (-115.0000000,  56.0000000) (115d 0'6.32"W, 54d 0'1.81"N)
>>> Lower Left  (-115.0000000,  54.0000000) (115d 0'6.32"W, 54d 0'1.75"N)
>>> Upper Right (-105.0000000,  56.0000000) (115d 0'5.77"W, 54d 0'1.81"N)
>>> Lower Right (-105.0000000,  54.0000000) (115d 0'5.77"W, 54d 0'1.75"N)
>>> Center      (-110.0000000,  55.0000000) (115d 0'6.04"W, 54d 0'1.78"N)
>>> Band 1 Block=11696x1 Type=Byte, ColorInterp=Red
>>> Band 2 Block=11696x1 Type=Byte, ColorInterp=Green
>>> Band 3 Block=11696x1 Type=Byte, ColorInterp=Blue
>>>
>>>
>>> On Sat, Feb 21, 2009 at 9:55 PM, Brian Murray <idlegod at gmail.com> wrote:
>>>> I'm trying to get all of it. :)
>>>>
>>>> It appears like a_allr is ok, but then when I apply the definition, it
>>>> only grabs a few meters of the real map...
>>>>
>>>> I think I must have to set the scale to something. I just don't know
>>>> what yet... I am going to sleep on it. I found some sites that have
>>>> some calculations for that now.
>>>>
>>>> On Sat, Feb 21, 2009 at 9:47 PM, Wendy Fay Stevenson <stevensw at erau.edu>
>>>> wrote:
>>>>> Um, it looks like it's doing what you're asking it to do.
>>>>> What corner points are you wanting?
>>>>>
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>>>
>>>
>>
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