Good info. Thanks, Mike.
Paul, W9AC
-----Original Message-----
From: Michael Tope
Sent: Sunday, June 22, 2014 7:39 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] SRTM Fill Data
Paul,
This document has a pretty good explanation of how the non-SRTM data was
blended to fill in voids:
https://lpdaac.usgs.gov/sites/default/files/public/measures/docs/NASA_SRTM_V3.pdf
Looks like they used data from the ASTER mission (GDEM2) along with USGS
NED data in the US (I think this is the 7.5 arcsec data you get on USGS
quad maps) and GMTED2010 data outside the US.
73, Mike W4EF................
On 6/21/2014 8:30 PM, Paul Christensen wrote:
Just discovered a data-filled version of the SRTM data:
http://earthexplorer.usgs.gov/
After the coordinates are entered into the "Search Criteria" tab, go to
the "Data Set" tab and instead of selecting SRTM, select "SRTM Void
Filled." Works well now on the northern shadowed side of the hill but not
sure how the fill data was collected nor its overall accuracy. Anyone
know?
Paul, W9AC
-----Original Message----- From: Paul Christensen
Sent: Saturday, June 21, 2014 10:48 PM
To: towertalk@contesting.com
Subject: [TowerTalk] SRTM Fill Data
Been trying to model the legendary W3CRA site using HFTA. I downloaded
the
SRTM 1 arc-second data in a .TIF format from the NASA website. All is
working well except that a few north bearings from the site appear to have
been data-shadowed during the year 2000 space shuttle capture. This shows
as a dead terrain zone between 900 ft to 2200 ft on the hill just north of
the site. That's a huge problem since HFTA heavily depends on the
mid-field terrain data. In researching this effect, apparently quite a
few
SRTM tiles require "fill data" from an alternate source.
I figured out how to merge .TIF data image tiles, but does anyone know how
to add fill data back into a .TIF file and exactly what 1 arc-second
source
to use? Tnx!
Paul, W9AC
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