Approach to work with large tin

[Cindy Lee]

Hi,

I received a 12da file, 2.2Gb that contains a tin about 200Ha area and it gets almost impossible to work with. Any method to work around this?

Regards,
Cindy

[Sam Cech]

you could try and make a Grid tin from it

[Cindy Lee]

Hi Sam,

I created the grid string but it doesn't seems to be too helpful as I need the surface for supertin. I couldn't use the grid string to create tin and the grid tin won't show for supertin.

Cheers,
Cindy

[Sam Cech]

ahh, super tins

perhaps you can contour the original tin, use Global utilities filter to remove points from those, and create a new tin from contours
there will be a quality degradation depending on contour interval, plus contours are not that great to tin, but it might reduce the data to something less than 2GB and hence usable

also, if you don't need all the data but only a small area, null by polygons might be away to remove all the triangles you don't need and hence reduce the tin

[Phil Davies]

have you tried just working with it in an opengl plan view?

[darren mckimm]

cindy

i use the following method to reduce the tin points.

Tins > Utilities > Grid DTM
this process creates strings over the extend of the large tin at set intervals. i tick the box to have 1 string per grid row. quicker selecting if you want to profile a row of points.
this then gives you a model of the tin in say a 1m or 2m interval.
then create a tin from this data and the resulting tin should be easy to work with whilst still maintaining most of the accuracy of the surface.