On Tue, 15 Jun 2004 10:41:04 -0500
"Curtis L. Olson" <[EMAIL PROTECTED]> wrote:
>>I recently
>>modelled a 40-story building I wanted to put in its real-life location;
>>the latlong I'd dug up for the building didn't match any of the antenna
>>locations, so I didn't know what to substitute for.
> You used to be online mapping services that would (directly or 
> indirectly) get you the lat/lon of things on the image, but I think they
> realized the usefulness of this and I haven't found anything for free 
> lately ... even mapquest seems to have gotten rid of their aerial photo 
> feature.

Terraserver still has a lat/lon search function; so by repeated tweaking
you can get a value if you know a good approximate value to start with.
And in principle, you can get that from various places that do address
--> lat/lon lookups (MapQuest still has a page that does this).  The
problem is that they seldom all agree with each other.  Last week, I
used MapQuest and another similar service to look up my home address; the
coordinates the two of them gave me differed by a half a kilometer.  I
then put each of those coordinates into terraserver's geographic search;
I got images back which were about five kilometers from where I live.

> If you live in the area you could drive over with a gps and survey the 
> building yourself ... drive around the block a couple times and record 
> the track?  Gps's don't work well in down town environments because the 
> satellites are often obstructured, but maybe you can get lucky enough to
> get a decent idea of the location.

Yeah, it's my ex-home-town, so not so easy to check it out.  But I am
planning on using a gps for D.C.-area landmarks shortly.

> Yes.  There are floating towers, there are extremely tall towers in the 
> middle of some runway approaches, there are towers that have multiple 
> antennas mounted to a single structure so you can have double towers on 
> top of each other.  It would be nice to calculate a FG ground elevation 
> for each tower so none of them are blatently floating.  There is a lot 
> of sanity processing that needs to be done and perhaps some hand 
> checking for blatent cases that interfere with runway approaches.

Hmmm.  For comparing against ground level altitude, I'd naively think one
would need to look at the binary data for the terrain.  But for checking
for towers on top of each other, and for towers right along runway
approaches, I'd think that wouldn't be too hard to check.  I'm sure I
could in a shell script + add-ons, or maybe python.  It would take some
cleverness to keep it from taking forever to do, though.  I presume
that you just have some script that generates entries for the towers in
relevant .stg files?  Do you do anything to the FCC ASR .dat files
(CO.dat, RE.dat, etc.) or do you parse them directly?


P.S.  Side question:  what would your opinion be as to the best way to
handle the National Mall, or NYC's Central Park, or any other large
green space in the middle of some other environment?  It seems like a
bad idea to create a 6000m x 800m plane in Blender and place that as
the Mall, for a number of reasons.  Can TerraGear be told to override
usage data and put grass within a region bounded by 3 or 4 locations?
(I guess this question may be better asked over in terragear-devel)

Chris Metzler                   [EMAIL PROTECTED]
                (remove "snip-me." to email)

"As a child I understood how to give; I have forgotten this grace since I
have become civilized." - Chief Luther Standing Bear

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