[gdal-dev] Warp a file from two separate Lat and Long

[Luisa Peña]

Hi Andrew

But How can I create those VRT, I never used those, from my original
binaries datasets  (HDF)? It seems that VRT is the key for my problem. But I
never used it before

Thanks for your help

Luisa
2010/2/18 Andrew Clegg <ancl at pml.ac.uk>

> Hi Luisa,
>
> I've tried something similar in the past with satellite data. I had 3
> files, containing latitude, longitude and value stored as floats. I had some
> very minor success with the following solution (I got out an image but it
> seemed to drop to a very low resolution). I'm posting it more in the hope
> that someone else may be able to spot what I did wrong, because I would
> still really like to be able to do this.
>
> My approach was to create a virtual dataset for each file:
>
> sst.vrt (the values):
>
> <VRTDataset rasterXSize="1296" rasterYSize="2030">
>  <Metadata domain="GEOLOCATION">
>     <MDI key="X_DATASET">lon.vrt</MDI>
>     <MDI key="X_BAND">1</MDI>
>     <MDI key="Y_DATASET">lat.vrt</MDI>
>     <MDI key="Y_BAND">1</MDI>
>     <MDI key="PIXEL_OFFSET">0</MDI>
>     <MDI key="LINE_OFFSET">0</MDI>
>     <MDI key="PIXEL_STEP">1</MDI>
>     <MDI key="LINE_STEP">1</MDI>
>  </Metadata>
>    <VRTRasterBand dataType="Float32" band="1" subClass="VRTRawRasterBand">
>    <SourceFilename relativetoVRT="1">sst.img</SourceFilename>
>    <ImageOffset>0</ImageOffset>
>    <PixelOffset>4</PixelOffset>
>    <LineOffset>5184</LineOffset>
>    <ByteOrder>LSB</ByteOrder>
>  </VRTRasterBand>
> </VRTDataset>
>
> lon.vrt (longitude): (latitude is basically the same)
>
> <VRTDataset rasterXSize="1296" rasterYSize="2030">
>  <VRTRasterBand dataType="Float32" band="1" subClass="VRTRawRasterBand">
>     <SourceFilename relativetoVRT="1">lon.img</SourceFilename>
>     <ImageOffset>0</ImageOffset>
>     <PixelOffset>4</PixelOffset>
>     <LineOffset>5184</LineOffset>
>     <ByteOrder>LSB</ByteOrder>
>  </VRTRasterBand>
> </VRTDataset>
>
> I then tried to run gdalwarp on sst.vrt, trying either '-geoloc' or '-to
> METHOD=GEOLOC_ARRAY'.
>
> Regards,
>
> Andrew Clegg
> Plymouth Marine Laboratory
>
> Luisa Peña wrote:
>
>> Greetings
>> I've used GDAL a few times but this is the first time that I'm lost on
>> what I can do with GDAL to solve my problem. I have 3 separate files, one
>> with my data, other with Lattitude and another with Longitude. They have the
>> same size and, as an example,  it means that Pixel (1,1) of data is located
>> in latitude retrieved from Pixel (1,1) from latitude and longitude (pixel
>> (1,1) from longitude). All of them are in WGS84 but without GCP's points. I
>> need to create a georreferenced/rectified Geotiff with this data and, to do
>> that, I need lat and Long. How can I do this?
>>
>> Thanks
>>
>> Best regards,
>> Luisa Peña
>> S.Paulo, Brazil
>> ------------------------------------------------------------------------
>>
>>
>> _______________________________________________
>> gdal-dev mailing list
>> gdal-dev at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/gdal-dev
>>
>
>
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