TIN Shift when Converting DTM

RE: TIN Shift when Converting DTM

caddcop — Wed, 25 Jun 2014 11:27:27 GMT

One way to test or to fix issues is to attache a feet file to a survey feet file. Then turn off true scale in the reference dialog box. The scale will change to 1.000002 to 1 or 1 to 1.000002 (or something with less or more zeros). Finally, change the 1.000002 to a 1.0 and the shift will vanish. Merge the reference into master and you will have a file with corrected feet.

This is more accurate than simply moving the data, as it really is a scale from xy-0,00 issue and not actually a shifted origin issue.

RE: TIN Shift when Converting DTM

kcaitch — Wed, 25 Jun 2014 11:07:37 GMT

CADDCOP,

I think you were on the right track. I can't seem to find the units that the TIN/DTM uses, but the Topo CAD file that was also delivered with the DTM had a mismatch in the units. I am not sure how it would have looked in InRoads, which is what they are using, but it obviously didn't work when we got it. After I adjusted the working units so they matched, it shifted the topo up about four feet. I then just had to move that info back down and now everything matches up.

Thanks for pointing me in that direction CADDCOP.

RE: TIN Shift when Converting DTM

kcaitch — Wed, 25 Jun 2014 10:24:02 GMT

If it is an issue with the units, I'm not sure why it will display correctly when I am using the original DTM file. Just in case, I created a DGN file with SF units (the original had plain Feet) and then tried to convert the DTM to a TIN file again, but the results were the same. Until I find the cause of the issue, I will just have to move the triangle elements and then redefine the TIN. But hopefully I can figure out what is happening in the conversion to really solve it.

RE: TIN Shift when Converting DTM

caddcop — Tue, 24 Jun 2014 20:37:32 GMT

Could it be a survey foot vs international foot issue? I don't use geopak but have seen similar issues.