Topic: Help with lisp Import data between autocad and google earth

[anhquang1989]

I find that there are many programs that switch between autocad and google earth.
But I can not use them in Vietnam because Vietnam uses a separate coordinate system that is VN 2000

Article 1. Now use the system parameters to switch between international coordinate system
WGS-84 ( zone 48 and 49)coordinate system of national and VN-2000 is as follows:
1. Parameter shifts the origin:
-191.90441429 M; -39.30318279 m; -111.45032835 m.
2. The coordinate rotation:
-0.00928836 " ; 0.01975479" ; -0.00427372".
3. Scaling length:
k = 1.000000252906278

Article2: With each province using a separate axis

http://alophukien.net/kinh-tuyen-truc-he-toa-do-vn2000-cho-cac-tinh

Look forward to your help.Thank you very much!

[VovKa]

I find that there are many programs that switch between autocad and google earth.

i believe you should contact the authors of those programs and ask for VN 2000 support

[anhquang1989]

Hi. Vovka.
I've seen them but most of the programs are build with vba and I still have not contacted the author.
Especially I love lisp so I hope to see it and I believe that some other countries have similar problems, so when it is established it will help a lot.

[VovKa]

some other countries have similar problems

i would not call them "problems"
it's a standard situation for coordinate systems that were realized before WGS84 era
and it could be worse
for example in Ukraine to covert old  soviet coordinates to the new WGS84 based system one must use not only axis shift and rotation but also affine transformations based on the TIN

[anhquang1989]

Yes. I agree with you.

[VovKa]

anhquang1989, today i had some free time to look closely into kml documentation
as a result i've written the function to convert dwg entities into kml format
i plan to add it to my IRT program (https://www.theswamp.org/index.php?topic=47908.0)

[anhquang1989]

That great. I really hope to see it.. thank you very much. Vovka