-------- Original Message --------
Subject: how to read a rotated grid
Date: Mon, 28 May 2012 09:29:52 +0200
From: MARTINEZ VADILLO, MIREN NEKANE <nmartinez@gamesacorp.com>
To: <Software.Services@ecmwf.int>

Good morning, this is Nekane Martínez and I hope you can help me.

I am trying to read a file with dataRepresentationType=10 (rotated) but
I cannot do it.

I don't find among the grib_api tools how I could derotated the grid so
I can know which is, for example, the temperature in a certain point

I have all the information in section 2 of grib_dump. But I don't find
the grib_api tool to derotate it.

Could you, please, help me?

====================== SECTION_2 ( length=46, padding=0 )
======================

1-3 section_length section2Length = 46 ( 0x00 0x00 0x2E )

4 unsigned numberOfVerticalCoordinateValues = 1 ( 0x01 ) [NV,
numberOfCoordinatesValues]

5 unsigned pvlLocation = 43 ( 0x2B )

6 codetable dataRepresentationType = 10 ( 0x0A ) [Rotated
Latitude/Longitude grid (grib1/6.table) ]

7-8 unsigned Ni = 582 ( 0x02 0x46 ) [numberOfPointsAlongAParallel, Nx]

9-10 unsigned Nj = 424 ( 0x01 0xA8 ) [numberOfPointsAlongAMeridian, Ny]

11-13 signed latitudeOfFirstGridPoint = -35500 ( 0x80 0x8A 0xAC ) [La1]

14-16 signed longitudeOfFirstGridPoint = -46500 ( 0x80 0xB5 0xA4 ) [Lo1]

17 codeflag resolutionAndComponentFlags = 136 [10001000] ( 0x88 )

18-20 signed latitudeOfLastGridPoint = 32180 ( 0x00 0x7D 0xB4 ) [La2]

21-23 signed longitudeOfLastGridPoint = 46460 ( 0x00 0xB5 0x7C ) [Lo2]

24-25 unsigned iDirectionIncrement = 160 ( 0x00 0xA0 ) [Di, Dx]

26-27 unsigned jDirectionIncrement = 160 ( 0x00 0xA0 ) [Dj, Dy]

28 codeflag scanningMode = 64 [01000000] ( 0x40 )

29-32 ascii zero = ( 0x00 0x00 0x00 0x00 )

33-35 signed latitudeOfSouthernPole = -35000 ( 0x80 0x88 0xB8 )

36-38 signed longitudeOfSouthernPole = -15000 ( 0x80 0x3A 0x98 )

39-42 ibmfloat angleOfRotationInDegrees = 0 ( 0x00 0x00 0x00 0x00 )
[angleOfRotation]

43-46 ibmfloat pv = 0 ( 0x00 0x00 0x00 0x00 ) [vertical.pv]

Thanks in advance

[Created via e-mail received from: "Software Services (DP)" <softserv@ecmwf.int>]