[OSRS-PROJ] The "almost" Lamber Conformal Conic Projection

Frank Warmerdam warmerdam at pobox.com
Mon Mar 3 21:54:04 EST 2003


Gerald I. Evenden wrote:
> The almost Lambert Conformal Projection, +proj=lcca, source code,
> test script and documentation are available at:
> 
> http://members.bellatlantic.net/~vze2hc4d/proj4/
> 
> The procedure only services the truncated series form of LCC to
> satisfy conversions of some French, North African and near Eastern
> interests.  It has only been tested for the northern hemisphere but
> if anyone knows of any usage in the southern hemisphere, let me
> know.
> 
> Please DO NOT use this projection for new applications.  It is
> only for handling existing usage.
> 
> Please let me know of any problems or have any suggestions.

Gerald,

I am incorporating the lcca into the remotesensing.org version of PROJ.4
but when I run the test script I don't get a close match to the EPSG values
you list.  Should I?

warmerda at gdal2200[60]% sh ~/lcca.tst
forward projection of:

34d08'11.291 37d31'17.625
15713.70        623182.75
EPSG guide 7, pdf p. 22 gives values of: 15707.96 623165.96

inverse check of forward

34d08'11.29100"E        37d31'17.62500"N


If I run the first step of the test script with -V I get:

warmerda at gdal2200[162]% ./proj temp -V +proj=lcca +a=6378249.2 +b=6356515.0 +nea
rly +lon_0=37d21 +lat_0=34d39 +k_0=0.99962560 +x_0=300000 +y_0=300000
#Lambert Conformal Conic Alternative
#       Conic, Sph&Ell
#       lat_0=
# +proj=lcca +a=6378249.2 +lon_0=37d21 +lat_0=34d39 +k_0=0.99962560
# +x_0=300000 +y_0=300000 +ellps=WGS84
#--- following specified but NOT used
# +b=6356515.0 +nearly
#Final Earth figure: ellipsoid
#  Major axis (a): 6378249.200
#  1/flattening: 298.257224
#  squared eccentricity: 0.006694379990
Longitude: 34d8'11.291"E [ 34.136469722 ]
Latitude:  37d31'17.625"N [ 37.5215625 ]
Easting (x):   15713.70
Northing (y):  623182.75
Meridian scale (h) : 1.00087594  ( 0.08759 % error )
Parallel scale (k) : 1.00089192  ( 0.08919 % error )
Areal scale (s):     1.00176864  ( 0.1769 % error )
Angular distortion (w): 0.001
Meridian/Parallel angle: 90.00000
Convergence : -1d49'37.527" [ -1.82709072 ]
Max-min (Tissot axis a-b) scale error: 1.00089 1.00088

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


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