Hi All,

Wanted to get your advise as to what type of Terrain DEM data I should be using for a Terrain Follow flight. I am testing out two different DEM's from Global Mapper, one is SRTM World wide Elevation data 1 arc second and the other is United States Elevation Data 10m. I notice that the SRTM elevation heights seem to correspond to Google Earth elevation heights. However, in the area I am looking to fly, there is a 10 meter elevation difference between the United States Elevation Data 10m and the SRTM World wide Elevation data 1 arc second. Have any of you come across this issue. If you which one would you go with?

Thank you,

Robert

Hope Dji give an answer you soon

CCAM, Do you know how the United States Elevation was generated and when?  We use SRTM data all the time with great results, assuming no changes since the shuttle missions were flown in 2000.  We fly mine sites, where they move a lot of dirt, so we occasional have to create our own terrain model.  Typically with do this by flying the area flat with GCPs in place, create a terrain model and then fly the area again with terrain following. We fly the same sites frequently so this work flow makes sense for us.  

Skyveyor112 Posted at 6-28 12:00
CCAM, Do you know how the United States Elevation was generated and when?  We use SRTM data all the time with great results, assuming no changes since the shuttle missions were flown in 2000.  We fly mine sites, where they move a lot of dirt, so we occasional have to create our own terrain model.  Typically with do this by flying the area flat with GCPs in place, create a terrain model and then fly the area again with terrain following. We fly the same sites frequently so this work flow makes sense for us.

Hi Skyveyor,

Below is a link of a study showing NED accuracy compared to SRTM. It tends to show that NED have more accuracy overall.

https://www.usgs.gov/land-resour ... ence_center_objects

CCAM Posted at 6-29 12:57
Hi Skyveyor,

Below is a link of a study showing NED accuracy compared to SRTM. It tends to show that NED have more accuracy overall.

@CCAM true, NED is generally a higher accuracy model, although one of the main sources of discrepancy between them is vegetation canopy and buildings, which in some cases can be a more important surface for terrain following than bare-earth...

CCAM Posted at 6-29 12:57
Hi Skyveyor,

Below is a link of a study showing NED accuracy compared to SRTM. It tends to show that NED have more accuracy overall.

@CCAM true, NED is generally a higher accuracy model, although one of the main sources of discrepancy between them is vegetation canopy and buildings, which in some cases can be a more important surface for terrain following than bare-earth...
in any event NED is available in 30m & 10m resolution, while SRTM in only 90m and 30m.

patiam Posted at 6-30 14:56
@CCAM true, NED is generally a higher accuracy model, although one of the main sources of discrepancy between them is vegetation canopy and buildings, which in some cases can be a more important surface for terrain following than bare-earth...
in any event NED is available in 30m & 10m resolution, while SRTM in only 90m and 30m.

Those are good points and something to be aware of.

Thank you,

Robert