Overlaying FAA Sectional Charts into Google Earth?

Also, ESRI has their own imagery service for World Imagery that uses satellites and aerial photos with a high resolution of 15m per pixel.

The sectionals from ArcGIS are from Feb 21, 2012.

reply to post by boomer135


Current FAA sectionals and TAC are dated March 8, 2012. FAA maps are usually dated around the 7th through 9th, so I assuming you are giving me the file date and not the date on the imagery itself.

Incidentally, GE imagery can be way better than 1 meter. Often they include aerial photography rather than just satellite imagery. This is especially true over urban areas such as KLAS. Mark Aubin, cofounder of Keyhole which became Google Earth, had a paper on this, though I don't see it anymore on the internet. I'm guessing Aubin left Google and his name has been erased from google literature.

Actually GE's imagery is 15m per pixel with a base imagery of 30m per pixel. They are currently working on a new imagery resolution of 2.5m per pixel but it's not out yet. Where did you find this way better than 1 meter? I don't think the American government would allow a non government company to use 1 meter per pixel. That's getting close to violating rights.

Actually I just found what you were talking about. Yeah there are some areas that have several pixels per meter, but like you said, they are mostly urban areas. But the majority of GE's imagery is 15m per pixel, for now.

reply to post by boomer135


Around the Nellis range, the resolution is far better than 15m. You can see the shape of those little creosote shrubs.

If you recall this thread, you can resolve a 1.5 meter stripe on the target:
www.abovetopsecret.com...

The target shown on the flickr account is located at
35.273025 -117.511883

You can resolve lines well under a meter on it. Unless someone beats me too it, I will measure that target the next time I pass through the area.

Note that resolution of the imagery versus what you can resolve are two different topics. Ultimately resolving imagery comes down to the MTF "(Modulation Transfer Function). The resolution is a function of contrast and spacing. Resolution targets have a series of stripes on them because it is more difficult to resolve a series of stripes than just one stripe surrounded by black space. If you really want to get technical, resolution should be described in terms of arcseconds. However people find arcseconds confusing, so for an optical system the rule is you specify the resolution at the point where the intensity of the white bars falls to 50%.

resolution and contrasst

The Sectional Charts from FalconView are old, thats right, but actually the ones that I am interested in are the TTR, UTTR, Groom Lake area (R-4808N), Edwards AFB, Vandenberg AFB, China Lake, and maybe White Sands. For some reason, i could not find any differences in how they appear compared to gariac's files.

The airspace frequencies are the same, for example, CTC Nellis on 126.65 for MOA Entry or something like that in nature. even the (R) boundries are the same.

But i agree, its always better to have an up to date sectional chart for navigation.

reply to post by darpa999


If you want frequencies, it is far better just to go to airnav.com and the NOTAM for the specific area. The graphical maps are updated far less often than simple text.

reply to post by gariac




I agree. Freq's change alot and some of them are probably obsolete as soon as the charts are updated.

As for arc seconds, I agree its a better way to see the resolution. But like you said they can get confusing for alot of people. General rule of thumb though is 1 arc second is equal to 30 meter resolution, i.e. 1/3 arc second is 10 meters and so on. I'm not an expert by any means, just a geography major, and we use them quite a bit.

FalconView is much like ArcMap, but I guess ArcMap is much much more user friendlly and does not require the SQL installation.

No, it doesnt require sql, but you can use it in arcmap if you want. It's actually a really convienient feature. we use it all the time for stuff. And the interface is really user friendly. no need to know what to type in the formula because it's mostly point and click.

reply to post by boomer135


It is tough to get the atmosphere much under 1 arcsecond. That is why space based telescopes are so valuable. Poking around the net, there are claims of 1/3 arcsecond viewing without adaptive techniques. [For space viewing, adaptive techniques requires and artificial star. I don't know if the scheme can be reversed, i.e. terrestrial viewing from space.]

Using s=r*theta, you can estimate the size of the spot on earth. S=arc length on the earth, and yes I know that is not accurate. I am using the small angle approximation. R is the radius. Not having a clue to how high recon birds do their polar orbit, the book of knowledge (wiki) indicates 1000km. One arcsecond is 4.8481368 µrad; That puts the spot on the ground at 4.84 meters. That is 4.84 meters per pixel, but that isn't necessarily the resolution. It wouldn't surprise me if you had to at least double that figure, i.e. white stripe next to black stripe. So maybe 1 arc second is about 10 meters, but it also depend on the exact altitude. I think your figure of merit is good, perhaps padded slightly.

Note that you can resolve telephone poles at Groom Lake from Tikaboo. That is maybe half meter resolution. Working backwards, you have theta in rads = s/r. It is about 40km to Groom from TIkaboo. That is about 12.5urad, or 2.6 arc seconds. With the barlow and camera sensor, I probably get a bit under 2 arcseconds.

reply to post by gariac


Yeah I was going off the book of knowledge as well : "Elevation data was recently Updated to 10m (1/3 arc second) Resolution for the united states from the previous 30m (1 arc second) resolution"
en.m.wikipedia.org...

Sorry on my phone so it's hard to cut and paste. Your way makes more sense but we know that Wikipedia never lies . Lol.

I created a kmz file from the Nellis range map and calibrated it as well as I could to google earth. The map itself looks like a scan and has some nonlinearities.

www.inplanesight.org...
The link is on this page. Note that the file is large and will take some time for it to be downloads and then more time for google earth to process it.