Has someone a good idea on how to store and display time seires data in
MapInfo?
An example of the data I have is eg. rainfall data that produces thousands
of records for one particular location over time.
Harald Sch�lzel
Economist Civil Engineer
c/o SOPAC South Pacific Applied Geoscience Commission
Private Mail Bag
Suva, Fiji
Tel: Business (679) 381 377 private (679) 386 236
Fax: (679) 370 040
Mailto:[EMAIL PROTECTED]
URL: http://www.sopac.org.fj/wru
-----Original Message-----
From: Malcolm Jones [mailto:[EMAIL PROTECTED]]
Sent: Sunday, 25 July 1999 23:53
To: [EMAIL PROTECTED]; [EMAIL PROTECTED]
Cc: [EMAIL PROTECTED]; [EMAIL PROTECTED]
Subject: MI RE: Flavours of Transverse Mercator
The bible reference for all TM usage today is:
Redfearn J C B (1948), Transverse Mercator Formulae, Empire Survey Review,
Vol IX, No 69, July, P 318-322.
It is just formulas, without integrals or differentials, and so easy to
understand.
Suggest you get a copy of this paper.
Mal Jones (Geodesy Jones)
89 Woodhall St, Stirling WA 6021, Australia
Tel: +61 8 9344 5232 Email: [EMAIL PROTECTED]
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of
Cliff Mugnier - University of New Orleans
Sent: Friday, 23 July 1999 03:46
To: [EMAIL PROTECTED]
Cc: [EMAIL PROTECTED]; [EMAIL PROTECTED]; [EMAIL PROTECTED]
Subject: GPS: Flavors of Transverse Mercator
Fernando,
The GCTP.FOR is a Fortran77 source file (free from the "USGS.gov" websites)
for
all of the map projections used by the U.S. Geological Survey. There are
two
data files associated with the source code that are included also. The math
was
documented by John P. Snyder (now deceased) in "Map Projections Used by the
U.S.
Geological Survey" Bulletin 1532, and later revised as "Map Projections - A
Working Manual" Bulletin 1535. Bulletin 1535 is better because it has more
projections and Mr. Snyder referenced me (ha, ha)! :-)
Anyway, Dr. Atef Elassal (now retired), then translated 1532 into Fortran
for
the USGS. That is GCTP - the General Cartographic Transformation Package
which
is specifically for cartographic applications within the United States.
That's
what the data files are for. GCTP is absolutely perfect for what it was
intended for - INSIDE THE UNITED STATES OF AMERICA ONLY ! ! ! ! !
Many, many commercial software packages worldwide use this as the basic
foundation for their coordinate transformation engine. I give it away to my
students as an example of "how not to do it." This is essentially useless
for
geodetic applications outside of the United States. It can oftentimes be
used
for cartographic applications outside of the U.S. IF AND ONLY IF the
computational accuracy (and precision) is not needed for mapping at scales
larger than 1:24,000!!!!!!!
If you are going to use this for a NON-geodetic application, this will do
just
fine. If you are doing geodesy, do not touch this code!
------------------------------------------------------
The ellipsoidal case of the Transverse Mercator was cooked up by Heinrich
Lambert in the middle 1700's. It was a mathematical curiousity that was
useless
for practical applications until the City of Hannover asked Professor Carl
Freiderich Gauss to do a geodetic survey of the city in preparation for a
new
set of accurate tax maps.
There are two things you cannot avoid in life; those are death and taxes.
Most
all geodetic research has been funded (since the late 1700's) for either tax
mapping purposes or military purposes looking for better and more efficient
ways
of killing people ...
Anyway, Gauss worked up an expansion of Lambert's formulae that his Ph.D.
students could follow in doing the grunt work of adjusting the Hannover
Triangulation Net on the Gauss-Conformal Transverse Mercator. Years later,
a
Prussian Artillery Office named Schreiber used a simplified form of the
Gauss-Conformal Transverse Mercator that was a specific truncation called
the
Gauss-Schreiber Transverse Mercator. Another Prussian Artillery Officer
named
Kr�ger came up with a more elaborate expansion of the infinite series. Yup,
it
is called the Gauss-Kr�ger Transverse Mercator. In the 1920's or 1930's an
Italian Professor in Italy came up with a local version for the Instituto
Geografico Militare, and his name was Boaga. Yup, the Italians use the
Gauss-Boaga Transverse Mercator. And so on and so forth for ALL the
ellipsoidal
projections used for Grids on topographic maps.
When looking at geodetic accuracy and computational precision at the
sub-millimeter level TO THE MULTI-METER LEVEL for coordinates many degrees
east
or west of the central meridian, the specific truncation of a Transverse
Mercator makes a big difference. Doing foreign work for bazillion-dollar
exploration, drilling, and production for oil wells in specific countries?
Pay
attention to your math. If you are doing UTM or DHG (Deutches Herres Gitter)
within a plus or minus 3 degree longitude distance from the Central
Meridian, it
will do fine.
Diddling with some X,Y coordinates for a Ph. D. dissertation? Unless your
Major
Professor is a geodesist or mathematical cartographer, they won't even know
the
difference.
Cliff
--
Clifford J. Mugnier ([EMAIL PROTECTED])
The Topographic Engineering Laboratory
Department of Civil and Environmental Engineering
UNIVERSITY OF NEW ORLEANS
New Orleans, Louisiana 70148
Voice and Facsimile: (504) 280-7095
-----------------------------------------------------------------------
Fernando wrote:
>
> Hello Cliff
>
> I am doctorate student that needs to program a convert from Gauss
> Kr�ger to lat. long and back. The ideal solution would be to get a
> Fortran code for this, but maybe that is too much luck, so I would be
> happy with any hint you can give me (if I do not have to buy any
> software or module, even better).
>
> I have already spent a lot of time looking for it in Internet and I have
> found nothing, except your name in 'users.netonecom.net' (1998).
>
> And I have another question that confuses me (I am a beginner on this):
> Is Gauss-Kr�ger the same Transverse Mercator, or there is an important
> difference?
>
> Thanks in advance for any help,
>
> Fernando
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