[OSRS-PROJ] Rectified Skew Orthomorphic...EPSG

[Gerald Evenden]

First the script of Mr. Smart's test data:

#!/bin/bash
echo "test data from John Smart (john.smart at caris.com)"
prog="../lproj"
parms="+proj=omerc +lat_0=4d00\'00.000N +lonc=115d00\'00.000E \
+alpha=53d18'56.9537 +gamma_c=53d7'48.3685 \
+k_0=0.999840 \
+y_0=5000000 +x_0=2000000 \
+a=6377298.560 +b=6356097.554 "
cat <<EOF >tempa
5d00'39.3328N  115d02'46.4797E  2595244.677 5554640.242
4d51'17.2684N  114d55'50.4365E  2582484.393 5537337.229
4d00'00.000N   115d00'00.000E   2590476.87  5442857.66
2d25'30.000N   111d08'00.000E   2161074.28  5268121.72
2d30'00.000N   111d16'00.000E   2175900.30  5276416.44
2d25'30.000N   111d16'00.000E   2175901.71  5268123.87
EOF
$prog -f '%.3f' -r $parms tempa >tempb
$prog -o -r $parms tempa | $prog -i -I -W4 $parms >tempc
echo "projection arguments:"; echo $parms
echo "original data"; cat tempa
echo "omerc forward projection"; cat tempb
echo "omerc inverse projection"; cat tempc
/bin/rm tempa tempb tempc

Note that this version still requires both alpha and gamma_c even
though they are interrelated---in this particular case.

Results from above script:

test data from John Smart (john.smart at caris.com)
projection arguments:
+proj=omerc +lat_0=4d00\'00.000N +lonc=115d00\'00.000E 
+alpha=53d18'56.9537 +gamma_c=53d7'48.3685 +k_0=0.999840 +y_0=5000000 
+x_0=2000000 +a=6377298.560 +b=6356097.554
original data
5d00'39.3328N  115d02'46.4797E  2595244.677 5554640.242
4d51'17.2684N  114d55'50.4365E  2582484.393 5537337.229
4d00'00.000N   115d00'00.000E   2590476.87  5442857.66
2d25'30.000N   111d08'00.000E   2161074.28  5268121.72
2d30'00.000N   111d16'00.000E   2175900.30  5276416.44
2d25'30.000N   111d16'00.000E   2175901.71  5268123.87
omerc forward projection
2595244.682     5554640.245     2595244.677 5554640.242
2582484.398     5537337.232     2582484.393 5537337.229
2590476.876     5442857.657     2590476.87  5442857.66
2161074.283     5268121.723     2161074.28  5268121.72
2175900.304     5276416.437     2175900.30  5276416.44
2175901.717     5268123.865     2175901.71  5268123.87
omerc inverse projection
115d02'46.4797"E        5d00'39.3328"N
114d55'50.4365"E        4d51'17.2684"N
115d00'00.0000"E        4d00'00.0000"N
111d08'00.0000"E        2d25'30.0000"N
111d16'00.0000"E        2d30'00.0000"N
111d16'00.0000"E        2d25'30.0000"N

Comparison is fairly good to the centimeter.

Who is correct to the millimeter?

Comments appreciated and many thanks to Mr. Smart.

On Feb 9, 2004, at 6:24 PM, John Smart wrote:

> Gerald et al
>
> These are some parameters and test points which have been used by 
> CARIS for
> Borneo RSO. As far as I can recall, these parameters were tested 
> against
> some local clients' survey calcution programs.
>
> Scaling lat        4-00-00.000N
> Central meridian  115-00-00.000E
> Skew Azimuth       53-07-48.3680
> Scaling factor     0.999840
> False North  5000000
> False East  2000000
> Ellipsoid a, b: 6377298.560 6356097.554
>
> geographic:
> 5-00-39.3328N  115-02-46.4797E
> 4-51-17.2684N  114-55-50.4365E
> 4-00-00.000N   115-00-00.000E
> 2-25-30.000N   111-08-00.000E
> 2-30-00.000N   111-16-00.000E
> 2-25-30.000N   111-16-00.000E
>
> grid:
> 2595244.677 5554640.242
> 2582484.393 5537337.229
> 2590476.87  5442857.66
> 2161074.28  5268121.72
> 2175900.30  5276416.44
> 2175901.71  5268123.87
>
> If I can be of further assistance, let me know. Incidentally, I have 
> the
> same kind of thing for Malayan RSO.
>
> John Smart - Senior GIS Analyst
> Marine Division
> CARIS      www.caris.com
> Tel:     +1-506-458-8533   Fax:   +1-506-459-3849
>
> CARIS has expanded to new office facilities. Our new mailing address 
> is:
> 115 Waggoners Lane, Fredericton, New Brunswick, E3B 2L4, Canada.
>
<snip>
_____________________________________
Jerry and the low riders: Daisy Mae and Joshua

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