Transfer elevation data global mapper to civil 3d

[sanetdikkumbura1950]

What is the most accurate way to get elevation data through GLOBAL MAPPER and create surface by civil 3d?

[cwr-pae]

I export as *.dem from global mapper and use that to build the surface. Make sure your projection matches the one used in C3D. Create the surface and add the dem to it instead of creating one from a dem. 

[Pointdump]

Hi Sanet,
I'm curious, why do you need to go through Global Mapper? Where is your data coming from?
Dave

[sanetdikkumbura1950]

Hi, @Pointdump 
I usually get elevation data via globalmapper. Is there another way? (location USA)

[Pointdump]

Sanet,
There's a huge amount of elevation data freely available from sources like >>>The National Map<<<.
Many states and counties also supply current elevation data.
Dave

[sanetdikkumbura1950]

@Pointdump 

Thank you very much sir for your advice. I also use arcgis, is it possible to get the same dem (3dep) through that?

[Pointdump]

Sanet,
Civil 3D has a little problem with DEM data. It uses the lower left of pixel instead of center. DEM is derivative data. Better to use the original LiDAR point cloud data.
Location? I'd try first to find state or county elevation data.
Dave

[sanetdikkumbura1950]

@Pointdump
Parcel ID 09F330101350110
Address 0 STONEWALL TELL RD
33.627163,-84.570913
Fulton County, GA
stateplane-1002-Georgia West

[Pointdump]

Sanet,
There's a world of freely available elevation data for that Fulton County area: Contours, DEM's, and LiDAR. See if one of these will suit.

https://gisdata.fultoncountyga.gov/datasets/GARC::contour-lines/about

https://gis.fultoncountyga.gov/apps/topodownloadmapviewer/

https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=2526

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/2526/index.html

Dave

[sanetdikkumbura1950]

@Pointdump
Hi,
Thank you very much for the information you sent. I got the lidar data. The coordinate system of my cad drawing is NAD83 Georgia State Planes, West Zone, US Foot (GA83-WF). But when .laz is converted to .rcp through autocad recap and imported into civil 3d, it is displayed in a different place. (When importing to civil 3d, I also imported according to "use geographic location".)
please help. 

[sanetdikkumbura1950]

Hi, @Pointdump 
Thank you very much for the information you sent. I got the lidar data. The coordinate system of my cad drawing is NAD83 Georgia State Planes, West Zone, US Foot (GA83-WF). But when .laz is converted to .rcp through autocad recap and imported into civil 3d, it is displayed in a different place. (When importing to civil 3d, I also imported according to "use geographic location".)
please help. 

[Pointdump · Accepted solution]

Sanet,
What did "Current" and "Target" look like when you brought the point cloud into ReCap?
The LAZ file I grabbed was horizontal degree units and vertical Meters. ReCap read the header information as "LL-HPGN".
Dave

[Pointdump · Accepted solution]

Sanet,
Horizontal transformation worked well on the LAZ file I grabbed. You'll need to check vertical units to see if they are OK.
Attached are drawing, ReCap files, and the original LAZ file. I filtered ground points in ReCap.
Dave

[Pointdump · Accepted solution]

Sanet,
"When importing to civil 3d, I also imported according to "use geographic location".
You brought the RCP file in as an XREF? I usually use Insert >> Point Cloud >> Attach. And set UNITS beforehand to US Survey Feet.
Dave

[ChicagoLooper]

Hello @sanetdikkumbura1950 

Depending on your SOURCE of elevation data, you can transfer the data from Global Mapper to AutoCAD friendly format, e.g. shapefile, dwg, etc.

For example, if your source is DEM (raster data), do this:

1. Make a grid file.
2. Create contours from the grid file.
3. Export the contours.

[ChicagoLooper]

<<Civil 3D has a little problem with DEM data.>>

Civil 3D inserts the DEM the same way it inserts all rasters, i.e. the lower left of each pixel. However, if you add the DEM as an FDO connection, then it inserts properly. (It treats the raster as an entity, not as a collective bunch of pixels.) As long as the raster is a rectangle and not an IRREGULAR shaped image, such as one with zig-zag edged(s), an FDO will insert correctly.

[sanetdikkumbura1950]

Hi, Dave Stoll,

Your help solved the problem. Thank you very much for your knowledge and your valuable time. Thank you very much.

[sanetdikkumbura1950]

Hi, @ChicagoLooper 
I mostly use usgs 3dep data, I think that data is more accurate for usa. What is the best way to export them to civil 3d?

Thank you,