[gdal-dev] get GCP from noaa L1b

[Ramiro Gonzalez]

Hi,

Function ProcessRecordHeaders in "formats/l1b/l1bdataset.cpp" subsamples the
GCPs of the l1b image, but the points are unordered an not equidistant.

I attached to TCK 2403  a patch that modifies this behaviour. I tested the
image attached to the ticket and seems to work ok(no error produced).

I also test the patched driver  with an image of Argentina and worked ok.

I'd like to know if I misunderstood the intention of the code and the points
in each line shouldn't be equidistant.

Thanks
Ramiro


2011/6/15 Andrew Brooks <arb at sat.dundee.ac.uk>

> Hi
>
> From memory the l1b driver doesn't use enough points to get proper
> geolocation because it sub-samples the 51 which are provided in the l1b
> file. The best solution (that recommended by NOAA) is to use lagrange
> interpolation across the 51 points. A lagrange algorithm has been provided
> in the ticket you referenced but nobody has added it to gdal. I think at the
> moment you could consider the l1b driver broken.
>
> Andrew
>
>
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