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

[Brian Murray]

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. :)

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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