[Talk-us] FCC Antenna Structure Import

Alan Mintz Alan_Mintz+OSM at Earthlink.Net
Tue Feb 9 21:46:33 GMT 2010


On Mon, 8 Feb 2010 15:35:20 -0600, Jeffrey Ollie <jeff at ocjtech.us> wrote:
 >On Mon, Feb 8, 2010 at 3:25 PM, Anthony <osm at inbox.org> wrote:
 >> On Mon, Feb 8, 2010 at 12:47 PM, Jeffrey Ollie <jeff at ocjtech.us> wrote:
 >>>
 >>> Â Â  <tag k="ele" v="278.9"/>
 >>
 >> By the way, what is the datum for the elevation figure?
 >
 >I don't believe that it is specified explicitly,
 >but the latitude and longitude are in NAD83
 >so I'm guessing that >the elevation is the same.
 >I convert the latitude and longitude to WGS84
 >using the GDAL Python bindings, I should probably
 >figure out if >converting the elevation is as easy
 >as adding a Z component when I do the conversion.

Unless I'm missing something, NAD83 is equivalent to WGS84 for the purpose 
of this source data (and most any practical purpose). They result in the 
same co-ordinates out to at least the 7th decimal place in degrees (~1 cm).

My experience with FCC license data in the past has been that it is usually 
good to no more than 6 seconds (i.e. less than 3 decimal places in 
degrees). This is because before the GPS era, license applicants often 
copied or adjusted to locations reported for other nearby licensees, and I 
don't think there was a rigorous spec for how accurate they needed to be 
(or it was something like 1 minute). The AS database is likely similar, 
though in the ones I worked on, they were accurate to 1 second (and some 
even to 0.1 second - still only ~0.000028 degrees).


--
Alan Mintz <Alan_Mintz+OSM at Earthlink.net>





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