[Talk-us] FCC Antenna Structure Import

Mike Thompson miketho16 at gmail.com
Tue Feb 9 21:57:53 GMT 2010

On Tue, Feb 9, 2010 at 2:46 PM, Alan Mintz <Alan_Mintz+OSM at earthlink.net> wrote:
> 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).
You are spot on (or within a meter).  Within the continental U.S,
NAD83 = WGS84 to within 1 meter.

> 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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