Author Topic: c3d surface from gis  (Read 6650 times)

0 Members and 1 Guest are viewing this topic.

cadtag

  • Swamp Rat
  • Posts: 1152
c3d surface from gis
« on: April 19, 2016, 12:51:46 PM »
I've done this before, and it worked.  this time, i'm getting nonsense results. :crazy2:

The source gis data is a shp file from Northwest Florida Water Management District, -- supposedly 2' contours from lidar for Holmes Co.

 The problems with my results is that I find it hard to believe than anywhere in N Florida has a 25' rise in 8 horizontal ft!..  And the elevations seem to be about three times higher than they should be. My supposed highest surface elevation of 433' is about 19 ft higher than the highest spot in the entire state!??!  and a single 50 acre parcel is unlikely to have 150' of relief in that area.

Any ideas out there?
The only thing more dangerous to the liberty of a free people than big government is big business

mjfarrell

  • Seagull
  • Posts: 14444
  • Every Student their own Lesson
Re: c3d surface from gis
« Reply #1 on: April 19, 2016, 02:39:52 PM »
meters?


and or send me link to your data source or the data to examine...
Be your Best


Michael Farrell
http://primeservicesglobal.com/

mjfarrell

  • Seagull
  • Posts: 14444
  • Every Student their own Lesson
Re: c3d surface from gis
« Reply #2 on: April 19, 2016, 03:31:58 PM »
found it....waiting for download and processing....will report
Be your Best


Michael Farrell
http://primeservicesglobal.com/

mjfarrell

  • Seagull
  • Posts: 14444
  • Every Student their own Lesson
Re: c3d surface from gis
« Reply #3 on: April 19, 2016, 05:12:02 PM »
they still have not sent me a download link...
Be your Best


Michael Farrell
http://primeservicesglobal.com/

alanjt

  • Needs a day job
  • Posts: 5352
  • Standby for witty remark...
Re: c3d surface from gis
« Reply #4 on: April 19, 2016, 05:17:14 PM »
they still have not sent me a download link...
It does have a lag at times, but check your spam folder to be safe. The download link email is from a gmail account.
Civil 3D 2019 ~ Windohz 7 64bit
Dropbox

cadtag

  • Swamp Rat
  • Posts: 1152
Re: c3d surface from gis
« Reply #5 on: April 20, 2016, 07:17:20 AM »
When I grabbed the entire Holmes Co 2' contour shp file, the verticals were off, but the horizontal data was fine.  The area landed where I expected, so it appears that the horizontal coordinates were being converted to feet properly, but elevation data stayed in meters.

I went back and tried with a custom area, picking a region close to the job, and with that area, both horizontal and vertical came in properly.

The only thing more dangerous to the liberty of a free people than big government is big business

mjfarrell

  • Seagull
  • Posts: 14444
  • Every Student their own Lesson
Re: c3d surface from gis
« Reply #6 on: April 20, 2016, 09:04:48 AM »
they still have not sent me a download link...
It does have a lag at times, but check your spam folder to be safe. The download link email is from a gmail account.
nope  nothing..I see our contract IT support is doing their job of keeping us from doing ours again
Be your Best


Michael Farrell
http://primeservicesglobal.com/

mjfarrell

  • Seagull
  • Posts: 14444
  • Every Student their own Lesson
Re: c3d surface from gis
« Reply #7 on: April 20, 2016, 09:49:06 AM »
When I grabbed the entire Holmes Co 2' contour shp file, the verticals were off, but the horizontal data was fine.  The area landed where I expected, so it appears that the horizontal coordinates were being converted to feet properly, but elevation data stayed in meters.

I went back and tried with a custom area, picking a region close to the job, and with that area, both horizontal and vertical came in properly.
good to hear!

of note the data is also available

http://viewer.nationalmap.gov/basic/?howTo=true
Be your Best


Michael Farrell
http://primeservicesglobal.com/

mjfarrell

  • Seagull
  • Posts: 14444
  • Every Student their own Lesson
Re: c3d surface from gis
« Reply #8 on: April 21, 2016, 09:24:24 AM »
OK, from the file/link you sent me
There is an XML file- that honestly looks like it isn't 'complete'
however the key piece of information in there is this snip:


-<cordsysn>

<geogcsn Sync="TRUE">GCS_North_American_1983</geogcsn>

<projcsn Sync="TRUE">NAD_1983_UTM_Zone_16N</projcsn>

</cordsysn>

So that data is in Meters and one would want to set a file up on the correct coordinate system before importing the shp file data.
Then either make a surface in that file and export via land xml into a file on state plane ft - to work with it in feet
OR
Query the data into a file set in feet and then make the surface.

Will test the surface now....

further it appears there is NO 1ft contour elevation data so only the 2' contour lines are of use
Be your Best


Michael Farrell
http://primeservicesglobal.com/

BlackBox

  • King Gator
  • Posts: 3770
Re: c3d surface from gis
« Reply #9 on: April 21, 2016, 09:56:00 AM »
I had a similar issue with COGO Points I needed to build a Surface that came from 3rd party - ended up importing the COGO Points into my drawing (FL83-WF, US FT), and simply 'scaling' the COGO Point's elevation via LISP. :-D
"How we think determines what we do, and what we do determines what we get."

mjfarrell

  • Seagull
  • Posts: 14444
  • Every Student their own Lesson
Re: c3d surface from gis
« Reply #10 on: April 21, 2016, 10:26:13 AM »
I think they fubarred something here...

the elevations in the DBF that go with the shape file are in feet....

so C3D is reading them and then scaling them and mucking up the actual elevation in the surface model

would have been so much better IF they had just given you the LAS file and not this shp file data.
Be your Best


Michael Farrell
http://primeservicesglobal.com/

mjfarrell

  • Seagull
  • Posts: 14444
  • Every Student their own Lesson
Re: c3d surface from gis
« Reply #11 on: April 21, 2016, 10:54:36 AM »
OK- bad data export/delivery method at work here.
I've studied the xml file included with the zip file pretty hard.

Nowhere in there do they tell the receiver that the data is UTM83-16F  (US Survey Feet)

With that set in my destination file the map query produces good usable results and the elevations match what is in the dbf that accompanies the 2ft contour shp file.

Everything after that is good.
Be your Best


Michael Farrell
http://primeservicesglobal.com/

alanjt

  • Needs a day job
  • Posts: 5352
  • Standby for witty remark...
Re: c3d surface from gis
« Reply #12 on: April 21, 2016, 10:58:44 AM »
Civil 3D 2019 ~ Windohz 7 64bit
Dropbox

cadtag

  • Swamp Rat
  • Posts: 1152
Re: c3d surface from gis
« Reply #13 on: April 21, 2016, 11:11:51 AM »
Thanks Michael, I appreciate your looking into it.  NWFWMD will send the LAS data, and I requested it for the county.  So their system sent me download links --- looks like just under 650 files, all in 7zip format.  I may try again and narrow down the requested area instead of the entire county.   :2funny:
The only thing more dangerous to the liberty of a free people than big government is big business

mjfarrell

  • Seagull
  • Posts: 14444
  • Every Student their own Lesson
Re: c3d surface from gis
« Reply #14 on: April 21, 2016, 11:12:03 AM »
http://viewer.nationalmap.gov/basic/?howTo=true
Cool.
Now I need to figure out how to work with a geopdf.

why?  there are other more friendly data formats available from those guys.
Be your Best


Michael Farrell
http://primeservicesglobal.com/