Last July, Cliff Mugnier, Jacques Paris, and Walter ... (I only kept the
last message of the thread in which Walter's family name is not mentioned)
had an interesting discussion about coordinate transformation from a "Dig"
site local coordinate system to a projected system, and about whether a
3-parameter rather than a 6-parameter (as in MapInfo) transformation could
suffice.
I have to import into MapInfo a DXF file (with coordinates from a local Non
Earth system) of a construction site of roughly 1 km x 1 km, and transform
these coordinates in a MTM system. Following Cliff's advice, I intend to
use a 3-parameter transformation with 2 points known in both coordinate
systems.
Quoting Walter from the abovementioned thread:
> > I would like to build a program (mbx) that asks the user- from
> > two points(is this enough?), both local and
> > national coordinates. The program then calculates the rotation
> > angle and the translation parameters. Then the user can give
> > a number of local coordinates and the program can calculate from
> > every local coordinates the national coordinates.
> > Is this possible with some simple goniometry and pythagoras?
> > Is there some information on this subject (books, internet)?
Walter, have you built this program? If so, is it available to others?
Thanks in advance.
_____________________________________________
Claude Lavoie
Service du soutien � la client�le
Direction des technologies de l'information
Minist�re des Transports du Qu�bec
35, rue de Port-Royal Est, salle 5.00 a
Montr�al (Qu�bec)
H3L 3T1
T�l�phone: (514) 873-6280
T�l�copieur: (514) 873-8203
Courriel: mailto:[EMAIL PROTECTED]
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