# [Proj] Roussilhe Projection

Maciek Sieczka werchowyna at epf.pl
Sun Oct 23 16:49:27 EDT 2005

```Oscar van Vlijmen wrote:
> Maciek Sieczka wrote:
>>Could you pass over results of your implementation based on points I
>>mention on http://bugzilla.remotesensing.org/show_bug.cgi?id=818? Just being
>>curios how they compare to main reference, Transpol 1.1.
>
>
> Here you go:
>
> The source of the Polish formulae says that the accuracy is 0.1 mm or
> better, so in my results ("x65,y65") 4 decimals are significant.
> x = northing, y = easting
> Source of formulae:
>   Leszek Janusz Jaworski [errors corrected by OvV]
>   http://www.atomnet.pl/~geodeta/2000/59text1.htm
> I copied the Transpol results from:
> http://bugzilla.remotesensing.org/show_bug.cgi?id=818

PROJ.4.4.9, sterea, output extended to 5 decimal places, says:

> Zone 1
> lat0=50d 37m 30s; lon0=21d 5m;
> x0=5467000; y0=4637000; m0=0.9998;
cs2cs -s -f "%.5f" +proj=latlong +ellps=krass +to +proj=sterea
+ellps=krass +lat_0=50d37'30 +lon_0=21d5' +k=0.9998

> lat=52; lon=19;
> x65,y65 = 5621984.46761389, 4493939.53052073
> TRANSPOL  5621984.46761     4493939.53053
5621984.47176   4493939.53118 0.00000

> lat=52; lon=23;
> x65,y65 = 5621672.5694778, 4768617.47513516
> TRANSPOL  5621672.56947    4768617.47513
5621672.57291   4768617.47400 0.00000

> lat=50; lon=23;
> x65,y65 = 5399258.64188843, 4774385.80471728
> TRANSPOL  5399258.64189     4774385.80471
5399258.64220   4774385.80359 0.00000

> lat=50; lon=20;
> x65,y65 = 5398055.09440493, 4559343.33173783
> TRANSPOL  5398055.09441     4559343.33174
5398055.09465   4559343.33180 0.00000

> Zone 4
> lat0=51d 40m 15s; lon0=16d 40m 20s;
> x0=5627000; y0=3703000; m0=0.9998;
cs2cs -s -f "%.5f" +proj=latlong +ellps=krass +to +proj=sterea
+ellps=krass +lat_0=51d40'15 +lon_0=16d40'20

> lat=52; lon=15;
> x65,y65 = 5664935.33351284, 3588182.16724147
> TRANSPOL  5664935.33351     3588182.16725
5664935.33338   3588182.16682 0.00000

> lat=52; lon=17;
> x65,y65 = 5663668.48971264, 3725507.13249269
> TRANSPOL  5663668.48971     3725507.13249
5663668.48972   3725507.13249 0.00000

> lat=50; lon=17;
> x65,y65 = 5441200.96694657, 3726500.89609692
> TRANSPOL  5441200.96695     3726500.89610
5441200.96470   3726500.89733 0.00000

> lat=51; lon=15;
> x65,y65 = 5553716.83369209, 3585638.29471454
> TRANSPOL  5553716.83370     3585638.29472
5553716.83417   3585638.29532 0.00000

As we can see Oscar's implementation of "System 65" is closer to
reference Transpol 1.1 than PROJ.4's sterea. Still wondering how rouss
would perform...

Oscar, what do you exactly mean saying "[errors corrected by OvV]"?

Maciek

--------------------
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http://katalog.epf.pl/

```