|
|
| GeoCommunity Mailing List |
| |
| Mailing List Archives |
| Subject: | [gislist] SUM: UTM coordinate system for Vietnam |
| Date: |
12/12/2003 05:10:00 PM |
| From: |
PHILIP GREYSON |
|
|
Truncated question (full question at bottom of post): >> "I'm trying to =
track down information on the UTM coordinate system used in Vietnam during =
the 1960s and 70s."
Apologies for the late SUM.
Thanks to all who responded (Beverly Richey, Rixanne Wehren, Melita =
Kennedy, Nick Seigal, Dean C. Mikkelsen, Jamie Whitters, John Emmett, =
Chuck Meyer, and Ned Horning). The system I was interested in was the =
Military Grid Reference System (MGRS). Beverly Richey pointed out that =
ArcView 3.x comes with an extension for converting between other coordinate=
s systems (e.g. decimal degrees) and MGRS.
Many pointed to links to NIMA (formerly the National Imagery and Mapping =
Agency but now the National Geospatial-Intelligence Agency (NGA), =
http://www.nima.mil/) for information.
Responses:
---------------------
Rixanne Wehren
I am not an expert, but this sounds like the UPS military grid=20
system. Here's a reference doc.
Department of the Army. Grids and References, TM5-241-1 (Washington DC,=20
Dept. of the Army, March 1983).
((Seen in Map Use and Analysis by John Campbell))
Hope you can find it.
Rixanne
------
Melita Kennedy
Hello Philip,
I would bet that the references are partial MGRS (military grid
reference system). If you're working from a map, there should be
information about the UTM zone and the latitude band being used.
MGRS is based on UTM. A 'full' MGRS string looks something like:
49PAS7734960514
This is the point 108E 15N based upon WGS84. The first two
digits are the UTM zone, 49. P is the latitude band (8N-16N).=20
The next two letters identify a 100km cell. The rest of the
numbers are the rest of the UTM coordinates. The UTM coordinates
for this same point are 177349 1660514. These are to the nearest
meter.
Now your coordinates have been cropped to 3 digits each. That
means they're to the nearest 100 meters.
I would suggest downloading the GEOTRANS software from NIMA. You
can use that to calculate the MGRS values for various points and
see if your coordinates match up.=20
http://www.nima.mil > Products and Services > Geodesy and Geophysics >
Click the Geospatial Sciences link on the top right > now the
Grids and Projections link in the left frame.
Scroll down to the bottom and choose the GEOTRANS link.
Melita
--=20
Melita Kennedy
Product Specialist
ESRI, Inc.
mkennedy@esri.com
---------------------------------------------
This is the standard UTM system used by the military, see ESRI documentatio=
n
for the basics on this projection. The letters you refer to are for sub
grids (see below). The UTM main grids are also lettered and the letters
refer to bands of 8 degrees lettered from south to north:
X: 84-72 deg. N. Lat.
W: 72-64 deg. N. Lat.
...
N: 0-8 deg. N. Lat.
M: 0-8 deg. S. Lat.
...
D: 72-64 deg. S. Lat.
C: 80-72 deg. S. Lat.
>From Lat 84 N and 80 S the Universal Polar Stereographic (UPS) projection =
is
used instead.
Washington, DC is grid 18S (zone 18, band S). Vietnam should be in zone =
48
& 49, band P & Q (8-16, 16-24 deg. N. Lat).
Each of these UTM grids is further divided into lettered grid squares
100,000 M on a side (with partial squares at the grid boundaries). I am
sorry not to know what order the lettering goes in. Perhaps you can get
that piece of info from someone else.
Hope that helps.
Nick Seigal
-----------------------------------------------
Phillip,
I am assuming this is the MGRS (Military Grid Reference System). If you
have AV 3.2 or 3.3, it is an extension -- all you have to do is copy it =
from
the extension directory to the ext32 directory and check it under =
extensions
when you bring up AV. I hope this is helpful.
Beverly K. Richey
GIS Analyst
Northrop Grumman Information Technology,
TASC
700 Blvd. South
Huntsville, AL. 35802
------------------------------------------------------
Hi Philip,
Please take a look at the following web-site of the European Petroleum
Survey Group. There is a sister group in the US, called the Americas
Petroleum Survey Group of which I am a member.
http://www.epsg.org/
There is an MSAccess Database that contains most of the information you
should be after for Vietnam. Please let me know if you have any questions.
The company I am with, GeoGraphs, also does consulting in the area of map
projections and datum's worldwide (geodetic problems) as applied to data
management and GIS.
Best regards,
Dean
Dean C. Mikkelsen, B.Sc. (Surveying Engineering), P.Eng.
--------------------------------------------------------------
Philip,
Try the Defense Mapping Agency (NIMA) Technical Manual 8358.1, specifically=
Chapter 3. It will let you know how the U.S. Military determines the two
character grid designator and the 6 digit coordinated based on UTM. It is
available at:
http
|
|
Sponsored by:
For information
regarding
advertising rates
Click Here!
|
