[Geotiff] Re: Geotiff site

[Frank Warmerdam]

Gilad Ronnen wrote:
> 
> Hello Frank,
> 
> I use Geotiff and wanted to check the archives from 
> _http://geotiff.maptools.org/geotiff.html_ but when I tried
> 
> The "threaded archives" link to 
> _http://www.remotesensing.org/geotiff/mail/maillist.html_ it did not work.

Gilad,

I have corrected this in CVS.  Thanks for the feedback.

> Btw, do you know the answer to my post on geotiff list ? I asked how to 
> make a meta file
> 
> For geotiff from the following data (china)
> 
> [lambert]
> 
> 37 103 20 40 37 103 1 1 6500 720 576
> 
> Origin degrees Lat = 37
> 
> Origin degrees Lon = 103
> 
> Standard Parallels Lower Lat = 20
> 
> Standard Parallels Upper Lat = 40
> 
> Center Lat = 37
> 
> Center Lon = 103
> 
> Center Location = 1
> 
> Cencer Aspect Ratio = 1
> 
> East-West Distance = 6500
> 
> Output image Size W = 720
> 
> Output image Size H = 576
> 
> Looks like it is lambert conformal conic 2sp, but how to retrieve
> 
>  the ellipsoid and tie points ?


Indeed, it looks like LCC2SP but with no ellipsoid or datum information.
Depending on your need for accuracy I would just suggest using WGS84.
Based on the image size, aspect ratio and center lat/long I would suggest:

Geotiff_Information:
    Version: 1
    Key_Revision: 1.0
    Tagged_Information:
       ModelTiepointTag (2,3):
          0                0                0
          -3250.0         2600.00           0
       ModelPixelScaleTag (1,3):
          9.0277777        9.0277777        0
       End_Of_Tags.
    Keyed_Information:
       GTModelTypeGeoKey (Short,1): ModelTypeProjected
       GTRasterTypeGeoKey (Short,1): RasterPixelIsArea
       GeographicTypeGeoKey (Short,1): GCS_WGS_84
       ProjectedCSTypeGeoKey (Short,1): User-Defined
       ProjectionGeoKey (Short,1): User-Defined
       ProjCoordTransGeoKey (Short,1): CT_LambertConfConic_2SP
       ProjLinearUnitsGeoKey (Short,1): Linear_Meter
       ProjStdParallel1GeoKey (Double,1): 20.0
       ProjStdParallel2GeoKey (Double,1): 40.0
       ProjFalseEastingGeoKey (Double,1): 0
       ProjFalseNorthingGeoKey (Double,1): 0
       ProjFalseOriginLongGeoKey (Double,1): 103.0
       ProjFalseOriginLatGeoKey (Double,1): 37.0
       End_Of_Keys.
    End_Of_Geotiff.

Best regards,
-- 
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent