BS: aerial photographs

Subject: RE: BS: aerial photographs
From: GUEST,leeneia
Date: 09 Jan 07 - 01:14 PM

Later - thought I'd share something interesting I found by way of saying thanks:

http://www.airphotousa.com/Funstuff/Samples/fullsize/elway-maze.jpg

Subject: RE: BS: aerial photographs
From: GUEST,leeneia
Date: 08 Jan 07 - 11:49 PM

This is all most interesting. I've looked at a log of web pages, and Amos, I will keep your faith in commercial firms in mind.

Subject: RE: BS: aerial photographs
From: nutty
Date: 08 Jan 07 - 11:32 AM

Clicking on IMAGES on the Google search page gives you a lot of options that can be narrowed using the "Advanced Search" facility.

Subject: RE: BS: aerial photographs
From: Rowan
Date: 07 Jan 07 - 10:53 PM

OK, here is my favourite story about air photos used for mapping purposes.

At the end of WWII the Americans had a huge number of personnel still in uniform and quite a lot of equipment that cried out to be put to good use. Much of both could be used for aerial photographic mapping and some heavy suggested "Why don't we do something that's never been possible before? Let's map Antarctica!"

You've got to hand it to Americans; even with the current disasters their hearts are definitely in the right place. So Operation Highjump was on its way. Fleets of aircraft (probably DC3s) were used to take simultaneous verticals and obliques to port and starboard. From recollection it was all on 5" square B&W negatives (and prints) with perfect 60% endlap for the verticals and 30% sidelap for the obliques. The whole continent was flown, with all the piccies filling a huge hangar "somewhere in America".

Trouble was, if you intend using airphotos for topographic mapping you need what surveyors call "Ground Control". This isn't Houston conversing with Dr Tom; this is prominently marked points on the ground that have had their positions on the earth's surface carefully recorded by surveyors. As far as the antarctic was concerned, the amount of it that had any (let alone good) Ground Control was 3/5 of 5/8 of FA. And 90% of the lanscape consisted of sastrugi which changed shape and position every time the wind blew.

C'est la vie!

Some good came of it all, however! The Americans, being good sports, made the piccies available to allies. The Australians had been operating scientific stations (ANARE) at both Macquarie Is. (technically part of Tasmania) and Heard Is. (an Australian Territory that has allowed more than one bar bet to be one with the question "What is the highest Australian mountain?" Most answer Koszciuzko -at a smidgin over 7000'- instead of "Big Ben" at double the height) since 1947, when Operation Highjump was at its height. [Sorry! Couldn't resist.]

The Australians got copies of the prints displaying Antarctica's coasts near Australia and found one displaying an almost perfect harbour. The next year, after the Kista Dan had finished with Heard Is. it sailed due south until it got to the antarctic coast. They took a punt on which way to turn (I forget whether it was "Port" or "Starboard") and two days later they entered the harbour, now named Horseshoe Harbour from its shape. In 1954 it became the base for the oldest continuously occupied station in Antarctica; it was where I spent 1969, along with 23 other Australians as well as four Americans working on the Pageos program. Enabling me to claim, with a completely straight face, "I'm a 69er!"

There wasn't much folk music there though.

Cheers, Rowan

Subject: RE: BS: aerial photographs
From: Charley Noble
Date: 07 Jan 07 - 09:47 PM

The other amazing thing I found when I was working as a Peace Corps teacher was that even young children in Ethiopia, once oriented to a familiar landmark had no trouble describing everything else they saw. They were not disoriented by the perspective of flying above the landscape as I had earlier imagined. This made aerial photographs of great use in my geography classes for explaining the concept of mapping. We actually ended up collaborating as I outlined the map of the region and they told me what was on the map.

I still have a set of about 30 of those aerial photographs. It will be interesting to see what changes have taken place in the 40 years since I was last there. Unfortunately the Google-World imagery is currently poor in Ethiopia except for major cities.

Charley Noble

Subject: RE: BS: aerial photographs
From: Rowan
Date: 07 Jan 07 - 05:52 PM

Landscape mapping in the anglophone countries has gone through several phases. Leaving aside the seriously historical stuff prior to the 19 century, most such mapping was either cadastral (for property boundaries, municipal rates -what Americans call taxes- and minor works) or topographic; the latter was done mostly for military purposes. It wasn't until the latter half of the 19th century that mappers got serious about geodetic surveying for land masses and started coordinating the global requirements. Once they had, the mappers started collecting the necessary data to fit all the info into geodetically respectable maps.

In the middle half of the 20th century (from the '30s to the '80s, in the "developed" world), aerial photos were the main method of acquiring topographic detail to put into these maps and air photos for this purpose were mostly 'verticals' although 'obliques' were also used. As an aside, there's a lovely story about such mapping photography that I leave for another time. Colour airphotos delivered an order of magnitude more info than B&W piccies but they weren't generally available (in Australia, at least) until the late '60s.

Then we started getting satellite photography, which removed some aspects of distortion inherent with aeroplane-based photography but introduced others. John is spot on about the coloration of satellite prints. The satellites use sensors recording (digitally) anything up to 25 wavelengths spread across the electromagnetic spectrum and customers select the ones they wish to combine for their own purposes; the term 'false colour' is used for such images. The resolution used to be 100' (30m) wide pixels on Landsat and 5m wide for SPOT but these have probably been changed since I last checked.

Such resolution is way below that of even routine aerial photography. Another problem for us southerners is that all the sensors were set to meet the requirements of the satellite owners, all of whom were from the northern hemisphere. Australian reflectivities (to say nothing of sensitivities) are quite different and I seem to recall the same is true for African landscapes, meaning we have to do our own fiddles (sorry, "massaging") for interpretive purposes.

The lack of perspective distortion means that most image processing for mapping (read "GIS") purposes is done from satellite data and air photography these days is directed mostly towards municipal and engineering works or 'personal' customers, all of whom are essentially possessors of private commercial data.

A bit long but intended to be helpful.

Cheers, Rowan

Subject: RE: BS: aerial photographs
From: Amos
Date: 06 Jan 07 - 07:28 PM

Commercial sites have archives which will cost you a lot less, if they will serve your purpose, than commissioning a fly-over for a detailed shot.

Commercial firms are equipped to do straight down shots, and can also geo-coordinate them digitally if you plan to integrate them into some geo-information system.

If you email large aero-photogrtaphy services and ask if they have something for (area) at (year) they can often provide the very thing. If it's an older analog file neg or copy they will scan it so you can have it digitally. Everything for a price, of course.


A

Subject: RE: BS: aerial photographs
From: Charley Noble
Date: 06 Jan 07 - 07:15 PM

John-

That giraffe must have a verrrrry lonnnnng neck!

Charley Noble

Subject: RE: BS: aerial photographs
From: JohnInKansas
Date: 06 Jan 07 - 06:35 PM

There seem to be few published "airplane views" recently. People do take them, one supposes, but they seem not to appear on the web. I'd suspect it's just too expensive to take a plane up to allow anything but closely controlled commercial marketing of the pictures.

Some of the old archives have lots of such views, but they're mostly from low altitudes and take in just a single "homestead" or part of a city block. An aunt had a nicely framed one of their farm front lot from a barnstormer who took the picture and then landed on the road out front to sell them the copy, ca. 1945(?) or so.

Modern airplanes aren't really equipped for looking down, so many of the less commercial shots end up with Something in the way that prevents a good pic.

John

Subject: RE: BS: aerial photographs
From: Stilly River Sage
Date: 06 Jan 07 - 11:44 AM

Titles and sizes from the place I linked to above:

Boston, Massachusettes From Space, 39x28
Chicago, Illinois From Space, 28x39
Detroit, Michigan From Space, 39x28
Europe, Western From Space, 37x28
Great Salt Lake, Utah From Space,39x28
Houston, Texas From Space, 28x39
Illinois, From Space, 39x28
New York City From Space, 28x39
New York, From Space, 28x39
Ohio, From Space, 28x39
Pennsylvania, From Space, 28x39
USA, From Space, 28x39
Washington DC From Space, 39x28

Canada Satellite Image 30x24
Cape Cod Massachusettes Satellite Image 36x24
Chicago Illinois Satellite Image 30x24
Earth at Night 23x35
Los Angeles California Satellite 24x36
Miami Florida Satellite Image 36x24
San Diego California Satellite Image 36x24
Texas Satellite Image 26x26

Subject: RE: BS: aerial photographs
From: GUEST,leeneia
Date: 06 Jan 07 - 10:01 AM

Thanks, everyone. I've been going to the sites mentioned, even the one with Ariel - thanks, Nigel. I've learned a lot. Next the DH and I will go to his office to use more sophisticated equipment.

Either satellite or aerial photos might work for my project, but as John says, the color of the satellite work is iffy.

Subject: RE: BS: aerial photographs
From: JohnInKansas
Date: 06 Jan 07 - 01:42 AM

A thought that popped up on looking back at the beginning of the thread:

It appears that what's actually wanted is "satellite photos," and the request was for "preferably in color."

Be aware that nearly all satellite pictures are in "false colors" of one sort or another. Generally a number of sensors sensitive to specific wavelengths are used, and the differences in reflectivities at the different wavelenghts give a lot of information about the ground level happenings. Some of the images published may resemble an "eyeball view," and some that are deliberately assembled to emphasize a particular surface phenomenon can be gorgeous - but a bit on the surreal side.

Looking at them on the web, and downloading them from there, one can see what you get; but if placing an order to purchase something for a wall hanging etc., some caution is advised that you look at samples of the same "format" before sending the check.

ADDEND RE the USGS: This is the official source also for "topographic maps," and some splendid samples are available on the web. The best USGS stuff available for download though is in "tabular format" something like a spreadsheet, giving elevations vs horizontal plane coordinates. A program is "available" for printing maps from these databases but 1) it's expensive, 2) it's unsupported since the guy who wrote the program retired and nobody else at USGS seems to know how it works, 3) the best description is "it's shareware written by a government beaurocracy."

(A "programmer" who wanted to produce a "real program" (Windows/Mac compatible?) for plotting this data might find a fairly good market with the mountaineering and other outdoorsy clubs(?), although a couple of commercial map outfits might try to object if it was too successful. Maybe they'd buy you out?)

John

Subject: RE: BS: aerial photographs
From: Rowan
Date: 05 Jan 07 - 11:31 PM

I can't supply any relevant answers to the original question, from here in Oz but some of the posters above have reminded me of a couple of things.

When someone on our local intranet discovered GoogleEarth and alerted the rest of us to the URL of our workplace on it I was intrigued about when the aerial photo had been taken. When I posted that question the game of narrowing the time window by using the usual types of photgraphic evidence was great fun. But it only works where the resolution is adequate and there seems to be no understandable rationale behind which areas in Oz have high (or low) resolution images.

With reference to stereo pairs of airphotos, it's a longstanding trick for municipal councils here to use them for identifying "unapproved" alterations to buildings. Instead of putting adjacent pairs from the same run under the stereoscope (as alluded to by Charley Noble), you put the photos from the earlier run under one mirror and the photos from the later run under the other mirror. When you are viewing the same 'location', the items common to both runs are 'seen' in 3D but items 'seen' in only one of the piccies will appear to be 'floating'. Most of them will be vehicles but house extensions and other alterations to buildings will also appear to be floating. A quick check of the database for whether the work was "approved" and Bob's your uncle.

Cheers, Rowan

Subject: RE: BS: aerial photographs
From: Bill D
Date: 05 Jan 07 - 02:28 PM

my spellchecker *beeps* at "aeriel"

'correct' is relative.

Subject: RE: BS: aerial photographs
From: Charley Noble
Date: 05 Jan 07 - 01:48 PM

Nigel-

Very cleaver! LOL

Charley Noble

Subject: RE: BS: aerial photographs
From: Nigel Parsons
Date: 05 Jan 07 - 12:51 PM

Ariel photography

or, with the correct spelling,
Aeriel photography

Nigel

Subject: RE: BS: aerial photographs
From: Charley Noble
Date: 05 Jan 07 - 09:16 AM

I would agree with John in Kansas that USGS probably provides the best quality aerial photography readily available in stereo pairs. However, you might luck out with GoogleEarth, depending on the level of resolution available for your area of interest.

Another question is whether you are interested in photography showing changes over time, or just coverage that is most current. USGS is probably the bet source for that.

One of the nasty tricks we used to play on geology students in aerial photography lab was to reverse the stereo pairs in the set-ups and ask them to explain what they viewed. When the stereo pairs are displayed normal what you see is a three-dimensional landscape that gives you the perspective of flying over the area. However, when the stereo pairs are reversed what you view is an alien landscape where rivers appear to run along the tops of ridges and hills appear to be crators. Our students, those who trusted their eyes, came up with all sorts of creative explanations. ;~)

Cheerily,
Charley Noble

Subject: RE: BS: aerial photographs
From: GUEST,leeneia
Date: 04 Jan 07 - 10:12 PM

Thanks!

Subject: RE: BS: aerial photographs
From: Adrianel
Date: 04 Jan 07 - 10:03 PM

Google Earth is interesting. When it debuted, I looked at the Rock of Gibraltar, and found it was flat to the sea. Now it actually looks like a Rock. However, Cape St. Vincent (spectacular 100 meter cliffs at the bottom lefthand corner of Portugal) is still at sea level. Also, as Spaw said, the definition is very variable. In much of our area (Boston MA), you can see cars in driveways. The village my sister-in-law lives in in France is barely recognizable as a village, let alone seeing houses, or even roads. That said, a half a loaf is better then no bread.

Subject: RE: BS: aerial photographs
From: Stilly River Sage
Date: 04 Jan 07 - 08:34 PM

There is a large map collection at the university where I work, and a number of them were on loan to a museum in Austin a couple of years ago. One of the maps in the exhibit was actually the personal property of a professor who helped curate the exhibit. It came from M-SAT in Rockville, MD, and was called "Texas From Space." If you visit here you'll find a number of maps for sale by this company. They have various parts of the U.S.

The cover story in this newsletter talks about the exhibit and gives some information as to why Dr. Francaviglia chose this map for the exhibit.

SRS

Subject: RE: BS: aerial photographs
From: catspaw49
Date: 04 Jan 07 - 01:55 PM

I love messin' with Google Earth. Our house doesn't show up well because the outlying regions have less resolution but the city regions are great. You can see the basketball hoop stand at my sister-in-law's house and two people playing!

At Connie and Wayne's place you can see the cars in the driveway very well and it appears there are a number of folks in the side yard (which is probably us having a cookout). The Soo Locks are pretty neat and you can see several lakes freighters coming in from Whitefish Bay.

The 3-D aspect looks aren't too bad either.   I used it to give Wayne directions to a motel where he was staying recently in Toledo. What was cool was that I could reference specific buildings for him as well as the roads themselves.

Spaw

Subject: RE: BS: aerial photographs
From: Bill D
Date: 04 Jan 07 - 12:07 PM

ohh..almost forgot....try TerraServer It might get you something.

Subject: RE: BS: aerial photographs
From: GUEST,leeneia
Date: 04 Jan 07 - 11:49 AM

Thanks for all the suggestions. I have a new project, but don't want to talk about it much in case it all falls through and I wind up with egg on my face.

Now to check out the suggestions above...

Subject: RE: BS: aerial photographs
From: beardedbruce
Date: 04 Jan 07 - 11:02 AM

http://www.geoeye.com/

Subject: RE: BS: aerial photographs
From: skipy
Date: 04 Jan 07 - 10:44 AM

Off track from original question, but,
there was a case a little while ago where a man went to look at the picture of his house (up for sale) in the estate agents window and his "mates" van was in the drive!
'nough said!
Skipy

Subject: RE: BS: aerial photographs
From: open mike
Date: 04 Jan 07 - 10:20 AM

i just remembered about http://www.topozone.com/

Subject: RE: BS: aerial photographs
From: open mike
Date: 04 Jan 07 - 01:59 AM

try U.S.G.S.
they have
stereo
photos

Subject: RE: BS: aerial photographs
From: JohnInKansas
Date: 04 Jan 07 - 12:56 AM

Try USGS Maps: Aerial Maps

The US Geological Service is the "official" distributor of maps from most of the agencies involved in any sort of charting (including air shots), although some agencies also distribute via their own offices. Most of the shots available are a few years old, so very recent stuff may not be released there.

Google also provides pretty good ones, but they won't allow me to connect via dialup. (They block downloads by slow people.) With Google you can browse to the place you want, and select the "zoom level" to get particular levels of detail - at least I've been told.

It you're looking for something for a wall hanging, you'd probably be best suited with something from a printer, rather than a download. If you're looking for information about your neighbor's nighty then Google is probably your best bet since it lets you browse and zoom.

John

Subject: RE: BS: aerial photographs
From: Cluin
Date: 04 Jan 07 - 12:25 AM

I can see my house and my van as well.

Not all areas have such resolution however. For instance the east side of town here isn't viewable

Subject: RE: BS: aerial photographs
From: Bert
Date: 04 Jan 07 - 12:19 AM

Colorado Springs has aerial photos on the City's web site.

Subject: RE: BS: aerial photographs
From: Bill D
Date: 03 Jan 07 - 09:52 PM

for example, I can see my house and identify the cars in the driveway.

Subject: RE: BS: aerial photographs
From: Bill D
Date: 03 Jan 07 - 09:44 PM

depending on HOW detailed and where it is, you can get some amazing ones free with GoogleEarth....some areas are done is great detail, some only lightly covered.

If you go to maps.google.com, you 'might' be able to tell how good the free ones are...

(GoogleEarth requires a fast connection, but some of use it, and might get you what you need. Care to say what it is?)

Subject: RE: BS: aerial photographs
From: Amos
Date: 03 Jan 07 - 08:46 PM

Why yes, I do. I my part of the country we get them from a small aerial photography company called Lenska Air, but there are a dozen companies for the region, and any of decent size have quite an inventory going back over time.

You can also arrange for custom overflights if you are interested in some corner they have no stock shots of.

Use Google or your Yellow pages to find one for the area you're looking for.


A

Subject: RE: BS: aerial photographs
From: Sorcha
Date: 03 Jan 07 - 08:45 PM

You might try Googling for LandSat or LanSat. Not sure which it is but that is what they do. My cousin used to work for them. How high a resolution do you want?

(Smile...do you want to see the Mongolian shepherd taking a pee?)

Subject: RE: BS: aerial photographs
From: GUEST
Date: 03 Jan 07 - 08:24 PM

Go ahead and answer it someone. This is hardball.

Subject: RE: BS: aerial photographs
From: Cluin
Date: 03 Jan 07 - 07:20 PM

Specific targets?

Subject: BS: aerial photographs
From: GUEST,leeneia
Date: 03 Jan 07 - 07:11 PM

(I am not a guest.)

Does anybody know where to purchase high-resolution aerial photographs of the United States, preferably in color?

Not all of the United States at once, of course. Just parts of it.