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V-Datum

Started by caroline, April 26, 2010, 03:42:15 PM

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caroline

hi,

I have read through the posts and technical manuals and I am still not clear about how V-Datum works or if I should be using it. I converted my offshore raster data to points (for Carpinteria Marsh in CA) per the V-Datum manual and then ran through V-datum. I subtracted the output elevations from the input DEM and the values were all the same (0.83 m) which is exactly the same parameter as the NAVD88 correction I input into my header file from NOAA. So why would I need to use V-Datum? To use it would I then convert the points back to raster (with land as no data?) and input into Slamm 6? How is this useful if all the values are the same?

V-datum also can integrate land and sea but the DEM I am using (and also one I am using in NC- Beauford area) has already integrated the ocean and the land together (both are using vertical datum NAVD88). If I did need to do this I am unclear how I would go about it. Thanks.

Caroline

Jonathan S. Clough

If you do not have a spatial map of vertical datum corrections (or if the spatial map is uniform) then there is no reason to utilize a raster map of VDatum values within SLAMM.  You should not require different VDATUM corrections for topography and bathymetry because the relationship between NAVD88 and MTL does not change.

Good luck!  -- Jonathan


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