Wrong projection between WGS84 and GDM2000/Peninsular RSO

[bladegun]

When converting between WGS84 and GDM2000/Peninsular RSO (EPSG:3375), result from proj4js are very different from the one produced by cs2cs or PostGIS.

Here is my code:

proj4.defs('EPSG:3375', '+proj=omerc +lat_0=4 +lonc=102.25 +alpha=323.0257964666666 +k=0.99984 +x_0=804671 +y_0=0 +no_uoff +gamma=323.1301023611111 +ellps=GRS80 +units=m +no_defs');

var c = proj4('EPSG:3375', 'EPSG:4326').forward([410042.053264524, 340750.457263734]);
// c is [98.6785691176469, 7.071110215716101]

With cs2cs:

cs2cs +proj=omerc +lat_0=4 +lonc=102.25 +alpha=323.0257964666666 +k=0.99984 +x_0=804671 +y_0=0 +no_uoff +gamma=323.1301023611111 +ellps=GRS80 +units=m +no_defs +to +proj=longlat +datum=WGS84 +no_defs
410042.053264524 340750.457263734
101d41'12.348"E 3d4'44.25"N 0.000

With PostGIS 2.2:

SELECT ST_AsText(ST_Transform(ST_SetSRID(ST_MakePoint(410042.053264524, 340750.457263734), 3375), 4326))

I get POINT(101.6867634 3.07895829999971). This matches the result from cs2cs.

It seems proj4js is having problem converting omerc projection. Is this a bug or something is wrong in the proj4 definition string?

[calvinmetcalf]

did you intend to close this ?

[bladegun]

Yes.

…

On Apr 4, 2017 7:25 PM, "Calvin Metcalf" ***@***.***> wrote: did you intend to close this ? — You are receiving this because you modified the open/close state. Reply to this email directly, view it on GitHub <#173 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ANfhASYp5jl4S_5UTUXdTQLPjI6fIAVhks5rsiiPgaJpZM4HcvGQ> .

[jratike80]

Why did you close the issue? Did you find that you did something wrong, does the issue not happen any more or what? Other users have similar problems.

[bladegun]

Initially I thought that the wrong conversion was caused by a bug. Then, I found out that it was not possible to implement such a conversion in a JavaScript library. So, I closed this issue.