Aerial and Satellite Maps

[TSCOM]

I have some questions about the history of aerial maps/photos. Are aerial maps taken by airplanes? For example historicaerials.com.

When did the US start taking aerial photos and when did they switch to satellite? I'm curious if they go further back than 1955.

 

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[Mackaydon]

The first images from space were taken on sub-orbital flights. The U.S-launched V-2 flight on October 24, 1946 took one image every 1.5 seconds.
Don.......
Source: Wiki

 

[Jesse James]

Here in PA we can get aerial photos as far back as 1939. That's the oldest I've come across. I believe they were taken for agricultural purposes. The come in handy for my research.

 

[geologyjohn]

I have been a geologist since the 1970's. I frequently use aerial photos in my work. Also for my TH'ing. The oldest stereo pairs of aerial photographs that I have used were a flight line flown in 1928. The oldest non-stereo photos I have looked at are WW1 battlefield reconn photos taken over France and Belgium. Geologyjohn

 

[Clay Diggins]

Aerial maps are images taken by airplanes, stitched together and then orthorectified. That's where the stereo pairs come in - to provide the Digital Elevation Model (DEM) to rectify photo distortions due to differences in elevation across the aerial image area.

Satellite images can provide aerial mapping but there are a lot of limitations that lower level airplanes don't encounter. The most familiar obstacle to good satellite imagery is the lower resolution. Other obstacles are atmospheric disturbance and angle distortion.

Aerial photography goes back all the way to the first cameras being carried on hot air balloons. I can't name an exact date off the top of my head but it was probably 1850 or slightly before.

 

[TSCOM]

Aerial maps are images taken by airplanes, stitched together and then orthorectified. That's where the stereo pairs come in - to provide the Digital Elevation Model (DEM) to rectify photo distortions due to differences in elevation across the aerial image area.

Satellite images can provide aerial mapping but there are a lot of limitations that lower level airplanes don't encounter. The most familiar obstacle to good satellite imagery is the lower resolution. Other obstacles are atmospheric disturbance and angle distortion.

Aerial photography goes back all the way to the first cameras being carried on hot air balloons. I can't name an exact date off the top of my head but it was probably 1850 or slightly before.

Good info, thank you.

 

[CincinnatiKid]

geologyjohn, please excuse my ignorance, but what are "stereo pairs"?
Thanks
Peace

 

[Mackaydon]

If I may jump in.......Two images of the same area, taken from different points of view are called stereopair.
Don......

 

[Clay Diggins]

Here is a simple but understandable illustration of how stereo pairs are used in orthorectification of aerial images.

Rectification by Stereoscopy

 

[redbeardrelics]

I have some questions about the history of aerial maps/photos. Are aerial maps taken by airplanes? For example historicaerials.com.

When did the US start taking aerial photos and when did they switch to satellite? I'm curious if they go further back than 1955.

Good info everyone.
TSCOM, on the historicaerials.com website, the first maps from my area to be corrected or adjusted by use of airplane, seem to be the ones from 1944. This can be discerned by using the "slide" feature, and checking to see how accurate the building locations are on the different maps, in relation to where the buildings are actually located on the more recent, and more accurate photographs taken from airplanes and space (if that makes sense). The maps in my area from 1944 onward are pretty darn accurate. The maps prior to that show errors and variances in distance and road angles etc., that were not corrected by having access to more accurate views from above ground.

 

[geologyjohn]

To Cincinnatikid: I guess that an easy way to answer your question is this. When you look at the stereo pair of photographs through a stereoscope, the images appear to form a single 3-dimensional photograph. Very good for studying topography. Geologyjohn