[Talk-us] Peaks

Nakor nakor.osm at gmail.com
Sat Oct 23 15:54:02 BST 2010

  On 10/23/2010 10:46 AM, Mike Thompson wrote:
> I can't speak in regards to the horizontal error, but in regards to
> the vertical error, GNIS elevation is taken from the National
> Elevation Dataset (NED).  The NED is a gridded dataset (30 meter
> posting I believe), and does not contain spot heights, which is what
> you want.  In other words, the NED contains the *average* elevation
> for each grid cell, not the peak elevation.
> Mike
So it looks like NPS would be more accurate for vertical. On the other 
hand I looked at NAIP imagery which is quite well aligned if I trust the 
road tracks I took. On that one GNIS seems to be closer to the ridge 
than NPS.

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