Romania National Grid (Stereo 70)

[markbutch]

Hi all,

I am currently trying to write a scipt for the MapInfo.prj file to
create a coordinate system for the "Romania National Grid (Stereo
70)"

The information I have been provided with is;

Stereo 70 ("stereo şaptezeci")
"Hristow" Oblique Stereographic, units are meters Ф0 = 46° North and
λ0 = 25° East of Greenwich False Easting = False Northing = 500 km m0
= 0.999750 uses the "Dealul Piscului 1970" Datum (Krassowsky 1940
ellipsoid)

My efforts to date is below, but I keep getting a Error message,
'Invalid distance units: 25.'

"--- Romania National Grid (Stereo 70) ---"
"Dealul_Piscului_1970", 7, 25, 46, 0.99975, 500000.0, 500000.0

If anybody could please shed some light I would very much appreciate
it. Thanks


Yours,
Mark.

[Mike Jamieson]

Try putting a 20 ahead of the 7 to indicate it is a stereographic projection.

"Dealul_Piscului_1970", 20, 7, 25, 46, 0.99975, 500000.0, 500000.0




Mike

[David R Sherrod]

Mark,
If you're still having trouble after applying Mike's suggestion, then the
script may also need a datum number. If I understand the Mapinfo prj file
coding correctly, a stereographic projection coding will need the following
sequence:
1. Projection number (20?)
2. Datum (???)
3. Units (7, for meters)
4. Origin long (your 25, corresponding to 25 degrees east)
5. Origin lat (your 46, corresponding to 46 degrees north)
6. Scale factor (0.99975)
7. False easting (500000.0)
8. False northing (500000.0

Some Web hits suggest the origin lat may be 45, not 46, but I have no
helpful knowledge. I tried to find the datum number but was unable. There
may be some affine transformation data available to make the transition
into a more widely used datum, but that's a whole new can of worms.
I'm unclear as to how MapInfo introduces support in the software for new
datums. If the program doesn't recognize a datum number, then it seems to
me you may be paddling in muddy waters.

Dave Sherrod
-----------------------------------------



"Mike Jamieson"
<mjamieson@taiga-
ltd.com> To
Sent by:
mapinfo-l@googleg <mapi...@googlegroups.com>
roups.com cc


04/29/2008 08:53
AM

Subject
Please respond to [MI-L] Re: Romania National Grid
mapinfo-l@googleg (Stereo 70)
roups.com

[Spencer Simpson]

You'll need a datum number after the 20 (which tells MapInfo it's a
stereographic projection) and the 7 (which tells MapInfo the coordinate
system is in meters):

"Romania National Grid (Stereo 70)", 20, ##, 7, 25, 46, 0.99975, 500000.0,
500000.0

The Dealul Piscului 1970 datum isn't directly supported by MapInfo (AFAIK,
through 8.5), so you'll have to define a custom datum and add the datum
number and parameters as described in the MapInfo User's Guide (Appendix G
in the manual for 8.5). The datum is based on the Krassovsky ellipsoid.

HTH
________________________________

Spencer M. Simpson, Jr.
Information Technology Coordinator
Baltimore Metropolitan Council
http://www.baltometro.org

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-----Original Message-----
From: mapi...@googlegroups.com [mailto:mapi...@googlegroups.com] On
Behalf Of Mike Jamieson
Sent: Tuesday, April 29, 2008 11:53 AM
To: mapi...@googlegroups.com
Subject: [MI-L] Re: Romania National Grid (Stereo 70)

Try putting a 20 ahead of the 7 to indicate it is a stereographic
projection.

"Dealul_Piscului_1970", 20, 7, 25, 46, 0.99975, 500000.0, 500000.0




Mike

-----Original Message-----
From: mapi...@googlegroups.com [mailto:mapi...@googlegroups.com] On
Behalf Of markbutch
Sent: Tuesday, April 29, 2008 3:27 AM
To: MapInfo-L
Subject: [MI-L] Romania National Grid (Stereo 70)

Hi all,

I am currently trying to write a scipt for the MapInfo.prj file to
create a coordinate system for the "Romania National Grid (Stereo
70)"

The information I have been provided with is;

Stereo 70 ("stereo saptezeci")
"Hristow" Oblique Stereographic, units are meters ?0 = 46° North and
?0 = 25° East of Greenwich False Easting = False Northing = 500 km m0

[Dragos]

Try this: it's verified!
"STEREOGRAPHIC70", 20, 1001, 7, 25, 46, 0.99975, 500000, 500000
Dragos Gabudeanu
Romania ...

[Spencer Simpson]

Datum 1001 is the "Pulkovo 1942" datum for Germany, based on the same
ellipsoid (Krassovsky) as Dealul Piscului 1970 datum for Romania.

In the past, I found myself using GRS 80 (datum #33) for NAD 83 (datum #74)
data, and nobody ever noticed.

So Pulkovo 1942 may get you very close, maybe even within the error of the
Molodensky transformation MapInfo uses for datum transformations. Or the
error introduced by not specifying a Bounds clause.

________________________________

Spencer M. Simpson, Jr.
Information Technology Coordinator
Baltimore Metropolitan Council
http://www.baltometro.org

Confidentiality Statement

This electronic mail transmission contains confidential information
belonging to the sender which is legally privileged and confidential. The
information is intended only for the use of the individual or entity named
above. If you are not the intended recipient, you are hereby notified that
any disclosure, copying, distribution, or taking of any action based on the
contents of this electronic mail transmission is strictly prohibited. If you
have received this electronic mail transmission in error, please immediately
notify the sender.

-----Original Message-----
From: mapi...@googlegroups.com [mailto:mapi...@googlegroups.com] On

Behalf Of Dragos
Sent: Tuesday, April 29, 2008 6:10 PM
To: MapInfo-L
Subject: [MI-L] Re: Romania National Grid (Stereo 70)

Try this: it's verified!
"STEREOGRAPHIC70", 20, 1001, 7, 25, 46, 0.99975, 500000, 500000
Dragos Gabudeanu
Romania ...

On Apr 29, 12:26 pm, markbutch <markbu...@gmail.com> wrote:
> Hi all,
>
> I am currently trying to write a scipt for the MapInfo.prj file to
> create a coordinate system for the "Romania National Grid (Stereo
> 70)"
>
> The information I have been provided with is;
>

> Stereo 70 ("stereo saptezeci")
> "Hristow" Oblique Stereographic, units are meters ?0 = 46° North and

> ?0 = 25° East of Greenwich False Easting = False Northing = 500 km m0

[gheta]

Dragos!

Projection "STEREOGRAPHIC70", 20, 1001, 7, 25, 46, 0.99975, 500000,
500000 is valid for the former MapInfo 7.8, but Codex or does not
correspond with the new projection GCS_Dealul_Piscului_1970,
Double_Stereographic.

Your gica_gheta