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What's the most accurate elevation tool on the net (freebie)



 
 
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  #21  
Old March 6th 12, 05:17 PM posted to alt.internet.wireless,rec.radio.amateur.antenna
Jeff Liebermann[_2_]
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Posts: 1,061
Default What's the most accurate elevation tool on the net (freebie)

On Tue, 06 Mar 2012 01:24:06 -0800, miso wrote:

On 3/5/2012 8:26 AM, Jeff Liebermann wrote:


Ok. Go thee unto:
http://www.cplus.org/rmw/english1.html
Follow the destructions at:
http://www.cplus.org/rmw/download/download.php?S=1
For maps, download the SRTM3 maps for your area from:
http://rmw.recordist.com


Oops. I meant the SRTM1 maps.
http://dds.cr.usgs.gov/srtm/version2_1/SRTM1/

I've used Radio Mobile and SPLAT!. I never got a warm and fuzzy with
Radio Mobile. Of course, it is a bit more complicated to use SPLAT!.


I've used both. Radio-Mobile has a very steep learning curve.
Important functions are buried deep into obscure menus, useless trivia
is scattered all over the menus, there's no logical sequence of
operation, and many of the terms require expertise in cartography.
Debugging errors is tricky as important items, such as the performance
characteristics of the radios, are scattered over a half dozen menu
pages. I find myself constantly referring to my cheat sheet in order
to get anything done. However, I haven't found anything else that
even comes close to what it does.

One obvious advantage to SPLAT! is it can analyze very large areas. Not
all that useful in the case of this wifi setup, but very useful in sigint.


http://www.qsl.net/kd2bd/splat.html
Splat is somewhat easier to use, but as you note, is designed to
display repeater coverage. It's less useful for close in coverage, or
showing coverage details, as in mountainous or urban jungle terrain.

Both programs put considerable effort into implementing complex
terrain models. For 2.4 and 5.7Ghz, optical line of sight is close
enough.


--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
  #22  
Old March 6th 12, 07:13 PM posted to alt.internet.wireless,rec.radio.amateur.antenna
alpha male
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Posts: 7
Default What's the most accurate elevation tool on the net (freebie)

On Mon, 05 Mar 2012 08:26:29 -0800, Jeff Liebermann wrote:

If you have problems, ask here, or preferably the Yahoo Radio-Mobile
group at:
http://groups.yahoo.com/group/Radio_Mobile_Deluxe/


The first problem I'm having is locating a Linux (Ubuntu) Radio Mobile
download ...
  #23  
Old March 6th 12, 08:02 PM posted to alt.internet.wireless,rec.radio.amateur.antenna
Jeff Liebermann[_2_]
external usenet poster
 
Posts: 1,061
Default What's the most accurate elevation tool on the net (freebie)

On Tue, 6 Mar 2012 19:13:12 +0000 (UTC), alpha male
wrote:

On Mon, 05 Mar 2012 08:26:29 -0800, Jeff Liebermann wrote:

If you have problems, ask here, or preferably the Yahoo Radio-Mobile
group at:
http://groups.yahoo.com/group/Radio_Mobile_Deluxe/


The first problem I'm having is locating a Linux (Ubuntu) Radio Mobile
download ...


Is that suppose to be some kind of thanks for doing your research?
In the future, if you need assistance, get it from someone else.

RM mostly runs under Wine:
http://radiomobile.pe1mew.nl/?How_to:Wine
The problems listed are not fatal as you can download the SRTM maps
manually, and can simply export the result as a Google Earth overlay
to obtain street map detail.


--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
  #24  
Old March 7th 12, 03:14 AM posted to alt.internet.wireless,rec.radio.amateur.antenna
miso
external usenet poster
 
Posts: 7
Default What's the most accurate elevation tool on the net (freebie)


Oops. I meant the SRTM1 maps.
http://dds.cr.usgs.gov/srtm/version2_1/SRTM1/

I've used Radio Mobile and SPLAT!. I never got a warm and fuzzy with
Radio Mobile. Of course, it is a bit more complicated to use SPLAT!.


I've used both. Radio-Mobile has a very steep learning curve.
Important functions are buried deep into obscure menus, useless trivia
is scattered all over the menus, there's no logical sequence of
operation, and many of the terms require expertise in cartography.
Debugging errors is tricky as important items, such as the performance
characteristics of the radios, are scattered over a half dozen menu
pages. I find myself constantly referring to my cheat sheet in order
to get anything done. However, I haven't found anything else that
even comes close to what it does.

One obvious advantage to SPLAT! is it can analyze very large areas. Not
all that useful in the case of this wifi setup, but very useful in sigint.


http://www.qsl.net/kd2bd/splat.html
Splat is somewhat easier to use, but as you note, is designed to
display repeater coverage. It's less useful for close in coverage, or
showing coverage details, as in mountainous or urban jungle terrain.

Both programs put considerable effort into implementing complex
terrain models. For 2.4 and 5.7Ghz, optical line of sight is close
enough.


My recollection of Radio Mobile is you need to crank down the minimum
angle that it sweeps to get any accuracy. Like I said, I prefer SPLAT!
for the accuracy. Even so, it is only as good as the NED. However, if
SPLAT! says you can see it, then you can see it. I thought Radio Mobile
was simple to run, at least for one transmitter at a time. Far easier
than SPLAT, which requires compilation parameters to set the array size.
Radio Mobile, at least when I read it, was stuck at 3600x3600. If you
exceed that array, and note it uses a 1/3 arc second grid, the program
interpolates.

The grid is 10 meters on a size for 1/3 arc second. That means you can't
"see" more than 36km. Plenty for wifi, not so good for repeaters or even
photography.

I generally do two runs with SPLAT. First I check the altitude when the
radio is to be located. If it doesn't match the topo map, I add the
difference in altitude to the transmitter height. Then run it again.

I have a 90 mile path to analyze, so I guess I'll see what these
programs can do lately. But if Radio Mobile is stuck at 3600 pixels,
that is a show stopper.


  #25  
Old March 7th 12, 03:25 AM posted to alt.internet.wireless,rec.radio.amateur.antenna
miso
external usenet poster
 
Posts: 7
Default What's the most accurate elevation tool on the net (freebie)


RM mostly runs under Wine:
http://radiomobile.pe1mew.nl/?How_to:Wine
The problems listed are not fatal as you can download the SRTM maps
manually, and can simply export the result as a Google Earth overlay
to obtain street map detail.




This guy got it going. ;-)
http://forum.winehq.org/viewtopic.ph...ab4164 902614


If Alpha Male has linux, why even screw with Radio Mobile? Just run
SPLAT!. For a small array, the KML SPLAT generates should be fine for
Google Earth. My issue was the array was too big to feed GE directly.

GE has an "aperture" size that doesn't appear to be consistent between
PCs. GE expects the images to be tiled with no tile larger than the
aperture. On my PC, that is 3600x3600. That is probably why you could
load the Radio Mobile output to GE.

Incidentally, there are programs designed to take a PNG and tile it, but
I never got them to work. But it has been a while since I tried them.
  #26  
Old March 7th 12, 03:52 AM posted to alt.internet.wireless,rec.radio.amateur.antenna
Jeff Liebermann[_2_]
external usenet poster
 
Posts: 1,061
Default What's the most accurate elevation tool on the net (freebie)

On Tue, 06 Mar 2012 19:14:32 -0800, miso wrote:

My recollection of Radio Mobile is you need to crank down the minimum
angle that it sweeps to get any accuracy.


True. 1 degree resolution at perhaps 20km is:
tan(1deg) * 20km = 350 meters
resolution. Not great resolution, but good enough for wide area
coverage. For wi-fi, the range is much less, so the "squares" shown
on the map will be correspondingly smaller.

Samples of wide coverage area RM calcs.
http://802.11junk.com/jeffl/coverage/k6bj/
We recently moved our tower and antenna, when the building that
previously supported them was demolished. So, I recalculated the
coverage. I believe I used 1 degree resolution.

than SPLAT, which requires compilation parameters to set the array size.
Radio Mobile, at least when I read it, was stuck at 3600x3600. If you
exceed that array, and note it uses a 1/3 arc second grid, the program
interpolates.


I'm too lazy to check the numbers right now. Maybe tomorrow.
Meanwhile, this article claims that Splat is limited to 3600x3600
while Radio-Mobile is limited to 2000x2000. No clue at this time
who's correct.

I have a 90 mile path to analyze, so I guess I'll see what these
programs can do lately. But if Radio Mobile is stuck at 3600 pixels,
that is a show stopper.


A 90 mile PATH (line) is quite different from a 90 mile radius
coverage (area) radius.


--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com
#
http://www.LearnByDestroying.com AE6KS
  #27  
Old March 7th 12, 04:02 AM posted to alt.internet.wireless,rec.radio.amateur.antenna
Jeff Liebermann[_2_]
external usenet poster
 
Posts: 1,061
Default What's the most accurate elevation tool on the net (freebie)

On Tue, 06 Mar 2012 19:52:36 -0800, Jeff Liebermann
wrote:

On Tue, 06 Mar 2012 19:14:32 -0800, miso wrote:


than SPLAT, which requires compilation parameters to set the array size.
Radio Mobile, at least when I read it, was stuck at 3600x3600. If you
exceed that array, and note it uses a 1/3 arc second grid, the program
interpolates.


I'm too lazy to check the numbers right now. Maybe tomorrow.
Meanwhile, this article claims that Splat is limited to 3600x3600
while Radio-Mobile is limited to 2000x2000. No clue at this time
who's correct.


Looks like the balloon trackers have the same problem with Radio
Mobile Deluxe.
http://showcase.netins.net/web/wallio/RMD.html
"The 2000x2000 software elevation matrix limits paths to
2000km for 1000m data (30-arc second), 200km for 100m
data (3-arc second) and 130km for 30m data (1-arc second)."

Now, go away so I can get some work done...

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com
#
http://www.LearnByDestroying.com AE6KS
  #28  
Old March 8th 12, 05:13 AM posted to alt.internet.wireless,rec.radio.amateur.antenna
miso
external usenet poster
 
Posts: 7
Default What's the most accurate elevation tool on the net (freebie)


It is a simple click to change the step size even down to 0.01 of a
degree in the polar plot, or just run a Cartesian plot where you can
specify down to one pixel resolution.

Jeff


Yes. I'm just mentioning cranking down the angle to save someone a few
meaningless runs. It didn't occur to me to do the math as you suggested,
but it makes perfect sense.

I was running the beta version of splat-hd. I could do 6 degree x 6
degrees at 1/3 arc second. Each degree is 3600x3600, so I could do
21600x21600. If you want to do "mountain-topping", you need that kind of
span.

Looking at the overlays I generated, I had to hack the output into 12 to
20 blocks, 3600x3600 at a time, to make it google earth compatible.
Hopefully the new version does this automatically.

I believe this was the program I was trying to get to work to do the
cookie cutting. Looking at the bug report, it still looks like it has
issues.
http://www.maptiler.org/


I got really good with GIMP to do the cookie cutting. Still a PITA.

  #29  
Old March 13th 12, 12:10 AM posted to rec.radio.amateur.antenna
external usenet poster
 
Posts: 61
Default What's the most accurate elevation tool on the net (freebie)

On Monday, March 5, 2012 7:33:45 AM UTC-8, alpha male wrote:
On Mon, 05 Mar 2012 15:30:57 +0000, alpha male wrote:

On Sat, 03 Mar 2012 19:43:47 -0800, Jeff Liebermann wrote:
(I wonder how they handle the constant
creep which occurs out here near the San Andreas fault line).


What I mean by that is that it's a right-slip fault, and it moves by
centimeters to inches each year (sometimes in feet to yards, both in
elevation and in position) ... but ... how do they know if the west side
moved north or if the east side moved south?

I wonder what they use for their frame of reference since it depends on
which side of the fault you're on if you want to say the west moved north
or that the east moved south.


WGS84 is a geographic coordinate system: it's referenced to the Prime Meridian and the Equator, not to any ground landmarks locally.

the digital elevation data is "accurate as of the date of collection". If a fault moves or someone engages in a big earthmoving operation, then the data set won't reflect reality.

As to the practical problem of determining plate movement? Easy if you have GPS, because GPS is referenced to WGS84, and WGS84 is referenced to a specific geoid, anchored at the equator and the prime meridian. In turn, one can use celestial landmarks to calibrate it.


 




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