[Proj] problem in projection

Noel Zinn ndzinn at comcast.net
Tue Feb 24 09:25:12 PST 2009


EPSG Projected CRS code 3106 comes very close.  It's Bangladesh Transverse
Mercator on the Gulshan 303 datum using Everest 1830 (1937 adjustment).  The
only projection parameter that differs is the False Northing, 0 in the case
of 3106 and -2M in your case (curious).  But this will be a static offset.  

I don't see a better candidate in the current dataset (6.18) that you can
download yourself at www.epsg.org.  The (rather garbled text) below is
extracted from the dataset for 3106.

I have no idea whether this information will be useful to you in Proj4.

Noel

                          International Association of
Detailed Report on Projected
 
Coordinate Reference Systems
                          Oil and Gas Producers



                           data set version         6.18.2
Search Criteria:   *bangladesh*



# 1      Cod   3106         Name:  Gulshan 303 / Bangladesh Transverse
Mercator

                        EPSG abbreviation: Gulshan  / Bangladesh TM

Base GeogCRS:         Gulshan 303
CS
 
axes:
Geodetic Datum:       Gulshan 303
Orde      Axis Name        Abbr                Axis Units
Orientation
 
1        Easting            E                    metre
east

 
2        Northing           N                    metre
north

 
CS           Used in projected and engineering coordinate reference systems.
Semi-major axis        6377276.345      metre
remarks:
(a) =
Map                Bangladesh Transverse Mercator
Inverse flattening     300.8017
Projection:
(1/f) =
Projection         Transverse Mercator
Prime Meridian:       Greenwich
 
Parameter Name              Parameter Value             Unit of
Datum origin:         Gulshan garden, Dhaka.
Measure
 
Latitude of natural origin             0°    0'         0”    N
                      observed and adjusted in 1995 by Japan
Longitude of natural origin           90°    0'         0”    E
                      International Cooperation Agency (JICA).
 
Scale factor at natural origin               0.9996              unity
 
500000              metre
CRS scope:            Large and medium scale topographic mapping
False easting
                      and engineering survey.
False northing                                 0                 metre

CRS remarks:

 
Projection
 
remarks:
CRS info. source:     Survey of Bangladesh via IGN Paris and Tullow
Data         OGP           Revision      22-Jun-06   Change      2006.470
                       Oil.
source:                    date:                     id:
CRS area of use:      Bangladesh - onshore and offshore.





-----Original Message-----
From: proj-bounces at lists.maptools.org
[mailto:proj-bounces at lists.maptools.org] On Behalf Of Milo van der Linden
Sent: Tuesday, February 24, 2009 9:54 AM
To: PROJ.4 and general Projections Discussions
Subject: Re: [Proj] problem in projection

BTM will probably be: Bangladesh transverse mercator

Zahid Parvez wrote:
> hi
>
> I have a shape file which I have to import in GRASS. Shape file is 
> consists of a shape file, a dbf file and a prj file.
> The prj file has following information.
>
> PROJCS["BTM",
> GEOGCS["GCS_Everest_1830",
> DATUM["D_Everest_1830",
> SPHEROID["Everest_1830",6377299.36,300.8017]],
> PRIMEM["Greenwich",0.0],
> UNIT["Degree",0.0174532925199433]],
> PROJECTION["Transverse_Mercator"],
> PARAMETER["False_Easting",500000.0],
> PARAMETER["False_Northing",-2000000.0],
> PARAMETER["Central_Meridian",90.0],
> PARAMETER["Scale_Factor",0.9996],
> PARAMETER["Latitude_Of_Origin",0.0],
> UNIT["Meter",1.0]] 
>
>
> I will be very grateful if anyone could help me to find the ESPG code .
>
>
> Best
> Md. Zahid Parvez
>
> ------------------------------------------------------------------------
>
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> Proj mailing list
> Proj at lists.maptools.org
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