[Geotiff] Encoding of "ETRS89 / ETRS-LAEA" (i.e. EPSG:3035)

[Pierre Soille]

The problem we face is how to encode the "ETRS89 / ETRS-LAEA"
(i.e. EPSG:3035) projection 'correctly' into GeoTiff Keys (see
http://www.ec-gis.org/sdi/publist/pdfs/annoni-etal2003eur.pdf for the
definition of this projection).

 From http://www.remotesensing.org/geotiff/spec/geotiff6.html#6.3.3.1
we could not find any ProjectedCSTypeGeoKey code for this projection.
Therefore, one is forced to user-define all relevant parameters.  This
is what we did.  The comprehensive list of defined parameters, their
values and a series of comments is included at the bottom of this
message (see also output of gdalinfo on a sample file which can be
downloaded at http://www.ec-gis.org/sdi/seminar/geotiff-sample.tif).

Unfortunately, most of the common packages are not capable to read and
interpret correctly the geoinformation stored in these GeoTIFF files.
We would like to understand if this is due to the way we generate
our files or to software inabilities to handle these files.  In the
latter case, we will try to convince software vendors to upgrade their
GeoTIFF readers.

In any case, we would also be grateful for feedback on the purpose and
proper use of the 'GTCitationGeoKey' and the 'PCSCitationGeoKey' which
often are used quite arbitrarily.


Pierre Soille and Peter Strobl

 

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Order is the following:

GeoKey Name

Value

comment

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GTModelTypeGeoKey

1

GeoTiff code for label: 'ModelTypeProjected'

 

GTRasterTypeGeoKey

1

GeoTiff code for label: 'RasterPixelIsArea'

 

GTCitationGeoKey

'JRC-EGCS'

refers to JRC's 'European Grid Coding System', here we encode that this is
our scheme, this is the only field for which we do NOT use an adopted
spelling, we also believe that stating 'ETRS89 / ETRS-LAEA' in this key 
is not
correct as a GeoTiff scheme is more than just a projection

 

GeograpicTypeGeoKey

4258

EPSG parameter COORD_REF_SYS_CODE for COORD_REF_SYS_NAME 'ETRS89', GeoTIFF
label is 'GCS_EUREF89'

 

GeogCitationGeoKey

'ETRS89'

spelling adopted from EPSG COORD_REF_SYS_NAME of COORD_REF_SYS_CODE 4258

 

GeogGeodeticDatumGeoKey

6258

EPSG DATUM_CODE for  DATUM_NAME 'European Terrestrial Reference System
1989', GeoTIFF label is 'Datum_European_Reference_System_1989'"

 

GeogPrimeMeridianGeoKey

8901

EPSG PRIME_MERIDIAN_CODE for PRIME_MERIDIAN_NAME 'Greenwich'

 

GeogLinearUnitsGeoKey

9001

EPSG uom_code for 'meter' (ISO 1000)

 

GeogAngularUnitsGeoKey

9102

EPSG uom_code for 'degree'

 

GeogEllipsoidGeoKey

7019

"EPSG ellipsoid_code for ellipsoid_name 'GRS 1980,' GeoTIFF label is
'Ellipse_GRS_1980"

 

GeogSemiMajorAxisGeoKey

6378137.0d

in Geographic System Linear Units (Key 2052)

 

GeogInvFlatteningGeoKey

298.2572221d

unitless

 

GeogPrimeMeridianLongGeoKey

0.0000000d

'Greenwich' in Geographic System Angular Units (Key 2052)

 

ProjectedCSTypeGeoKey

32767

'user defined', the EPSG COORD_REF_SYS_CODE 3035 is not implemented in
GeoTiff!!!

 

PCSCitationGeoKey

'ETRS89 / ETRS-LAEA'

spelling adopted from EPSG COORD_REF_SYS_NAME of COORD_REF_SYS_CODE 3035,
this is the proper place for the projection name

 

ProjectionGeoKey

32767

'user defined'

 

ProjCoordTransGeoKey           

10

GeoTIFF code for label: 'CT_LambertAzimEqualArea'

 

ProjLinearUnitsGeoKey

9001

EPSG uom_code for 'meter' (ISO 1000)

 

ProjFalseEastingGeoKey

4321000.0d

in Projection System Linear Units (Key 3076)

 

ProjFalseNorthingGeoKey

3210000.0d

in Projection System Linear Units (Key 3076)

   

ProjCenterLongGeoKey

10.000000d

in Geographic System Angular Units (Key 2054)

 

ProjCenterLatGeoKey       

52.000000d

in Geographic System Angular Units (Key 2054)

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