LIDAR conversion to Google Earth for contour lines?

[off_...@outlook.com]

G'Day -

Background first - I do residential design work with sophisticated 3D modeling software ArchiCAD. I want to find the simplest way possible to generate contour lines form LIDAR data, from which I can extrapolate a real world terrain model for my site plans and elevations. I work in Island County Washington where 2014 LIDAR data is available for free as source information. So conversion is the key. After much searching I have landed here, thinking perhaps I have interpreted this is a real possibility, and am hoping someone patient and tolerant can assist me.

I am WAY, WAY out of my depth when it comes to GIS work, even though I have dabbled with ESRI ArcMap. Google Earth seems much more user friendly and I am hoping to be able to generate real world contour lines for my site plans in Google Earth.  What I am after is a terrain model, hopefully generated in Google Earth that is driven by visable contours rather than X,Y,Z data,  [which yield nothing but a lot of triangles.] I was able to manage this process in ArcMap but it was a labor intensive process of converting, converting, tuning, and clipping, then exporting to .DWG etc. It became too much. I want to spend time designing houses not trying to learn how to pilot another complex software.

My design software ArchiCAD does have the ability to generate a mesh, or terrain model, from X,Y,Z data but it doesn't convert this to contour lines as you'd see on a site plan. 

Perhaps this is a "big ask" and I am still in way over my head, but like Mom always said, "the only stupid question is the one you don't ask."

I look forward to any and all productive commentary.

thanks -

jeff

  

 

[Harvey Greenberg]

You do not want to build a terrain model from contour lines.
Consider the 10m DEMs that were built across much of the USA from
(mostly) 40-foot contours. If you generate 40-foot (12.196m)
contours from these DEMs, they will resemble the original
contours. But if you try to build 50-foot contours from the DEM,
you will an ugly result, because the DEM is not well interpolated
from the contours. I have never seen a good algorithm for
creating a DEM from contours. (Yes, I pissed off some people when
I wrote about this issue twenty years ago. Are they still paying
attention?) I suspect that the world has moved on, and few people
see the need to build better algorithms to build DEMs from contours.

You already have a raster DEM, and you can build triangles from
points if you wish. If you want contour lines, you want them only
for visualization. You do not need dwg files; the shapefile
format is readable by GIS and googleEarth, and probably by most
contemporary CAD programs. I think they should all support 3D
contour lines.

Most contour lines are drafted by cartographers. Machines do not
making pretty lines. You will need to spend some time ,
generalizing, splining, and deleting extraneous loops. Someone
may volunteer a recipe, but recipes tend to vary with particular
circumstances.

--harvey

On 4/20/2016 4:15 PM, off_...@outlook.com wrote:
> G'Day -
>
> Background first - I do residential design work with
> sophisticated 3D modeling software ArchiCAD. I want to find the
> simplest way possible to generate contour lines form LIDAR data,
> from which I can extrapolate a real world terrain model for my
> site plans and elevations. I work in Island County Washington
> where 2014 LIDAR data is available for free as source

> information. So conversion is the key.After much searching I

> have landed here, thinking perhaps I have interpreted this is a
> real possibility, and am hoping someone patient and tolerant can
> assist me.
>
> I am WAY, WAY out of my depth when it comes to GIS work, even
> though I have dabbled with ESRI ArcMap. Google Earth seems much
> more user friendly and I am hoping to be able to generate real
> world contour lines for my site plans in Google Earth. What I am
> after is a terrain model, hopefully generated in Google Earth
> that is driven by visable contours rather than X,Y,Z data,
> [which yield nothing but a lot of triangles.] I was able to
> manage this process in ArcMap but it was a
> labor intensive process of converting, converting, tuning, and
> clipping, then exporting to .DWG etc. It became too much. I want
> to spend time designing houses not trying to learn how to pilot
> another complex software.
>
> My design software ArchiCAD does have the ability to generate a
> mesh, or terrain model, from X,Y,Z data but it doesn't convert
> this to contour lines as you'd see on a site plan.
>
> Perhaps this is a "big ask" and I am still in way over my head,
> but like Mom always said, "the only stupid question is the one
> you don't ask."
>
> I look forward to any and all productive commentary.
>
> thanks -
> jeff
>
>

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--
http://gis.ess.washington.edu/
hgr...@uw.edu 374 Johnson Hall 206-685-7981

Harvey Greenberg
University of Washington and the*Puget Sound Lidar Consortium*
Department of Earth and Space Sciences
College of the Environment
Box 351310
Seattle WA 98195-1310

[Steven Farwell - NRCS, Fort Worth, TX]

Hello Jeff, A cool program that I have used is called “3DEM software for Terrain Visualization”; this program will import LAS files and export them has different types of elevation products:

 

http://www.hangsim.com/3dem/

 

Even though I have not used this type of product called “XYZ scattered point topographic data files” ; looks like  3DEM can output this type of product from LAS or Lidar data.

 

Regards,

 

Steve

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[Evon Silvia]

If contours are really all that you're after, and 5ft contours would suffice, you can download them directly from Island County's GIS page: https://www.islandcounty.net/maps/data/

Higher resolution contours might be available if you contact the county directly, especially if it's the 2014 Island County LiDAR project we produced at WSI/QSI.

Once you have your contours, simply clip them to your study area in your favorite GIS program and they'll be in a size that your CAD software can probably manage. I've found that CAD software starts to struggle going over 300 acres or so.

As for your original question... I don't think Google Earth can generate contours or DEMs in the first place. Are you just hoping for KML-format contours from the LAS files? In that case, for Martin's tools check out "las2iso" and export a SHP or KML. Use the built-in filtering arguments (e.g., keep_xy) to pare down the LiDAR data to an extent that your CAD software can support before producing the contours. 

Hope that helps.

Evon

--

Evon Silvia PLS Solutions Developer 517 SW 2nd Street, Suite 400, Corvallis, OR 97333 P: (541) 452-8502 E: esi...@quantumspatial.com

--