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Aerial mapping information
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Author:  bobyar2001 [ Fri Mar 11, 2005 11:57 am ]
Post subject:  Aerial mapping information

Ran across this on the Cripple Creek RRs Yahoo group, thought some might be interested:

Whether you live near enough to visit your favorite railroad's old "stomping
grounds" or not, you may be interested in this alternative way of exploring
the terrain.

There are several ways of using the internet to display high resolution
satellite photographs of any point in the continental United States. The
best I've found is called World Wind. World Wind was developed by NASA, and
is freely downloadable. Be warned, however, that you will need several
Gigabytes of free disk space, a fairly speedy processor, a good 3D graphics
card, and a fast internet connection to use this program. Find out more
about the program and download it at <http://worldwind.arc.nasa.gov/>
http://worldwind.arc.nasa.gov/.

When you run WorldWind, you are presented with a view of the Earth from
space. Using the mouse, you can rotate the globe to your point of interest,
then zoom in from virtual earth orbit to a few hundred meters in altitude.

The program allows you to view several different "datasets" (think
"different sets of photos"). The "USGS 1m ortho" dataset is the best for
viewing details in the Cripple Creek area. For example, I've used a view
like this to research the railroad scale I mentioned in my last posting.

Not only can you "look" straight down at aerial photos, but you can "tilt
the camera", so to speak, to view the terrain in perspective. You can "fly"
over the terrain. This is particularly interesting for Colorado railroads,
where you can fly over the right-of-way as it weaves through mountain
passes. :-)

Resolution is fairly good. You can, for example, zoom in on the Colorado
Midland roundhouse in Colorado City; it's easy to identify by it's
distinctive shape. It's also easy to trace the old railroad right of ways in
the Cripple Creek district.

Resolution is much higher in certain urban areas. You can, for example, zoom
in on Disneyland and easily see individual rides. Here's a web site where
people post their favorite WorldWind views:

http://www.worldwindcentral.com/hotspot ... .php?id=41
<http://www.worldwindcentral.com/hotspots/view_hotspot.php?id=41&mode=full>
&mode=full

If your computer isn't up to the task of running World Wind, you might try
Terrafly (www.terrafly.com). This web site allows you to browse the same
USGS photo dataset using just your web browser and the Java plug-in. You may
use the site for free; however, the images are watermarked with the TerraFly
logo unless you pay to become a subscriber.

There are other sites as well. The USGS keeps a list at
<http://geography.usgs.gov/partners/viewonline.html>
http://geography.usgs.gov/partners/viewonline.html.

Though it doesn't allow you to "fly" (have the image pan across your screen
as if you were flying), the Microsoft TerraServer site allows you to browse
the same aerial photos. Follow the following link to see an aerial photo of
the Cripple Creek MT depot (now the museum). Can you see the wye?


<http://terraserver-usa.com/image.aspx?T=1&S=10&Z=13&X=2425&Y=21443&W=2&qs=%
7ccripple+creek%7cco%7c>
http://terraserver-usa.com/image.aspx?T ... 43&W=2&qs=%7
ccripple+creek%7cco%7c

--
Jon Sawyer

Author:  Frisco1522 [ Sat Mar 12, 2005 12:15 am ]
Post subject:  Re: Aerial mapping information

Does anyone know of a site where old aerial photos from USGS are accessible? I'm talking 30s-40s, etc. I think the whole country was photographed around 1940 for map purposes.
I've looked around the net with no luck so far.
It would be dynamite to look at our favorite yards or roundhouses from that long ago.

Author:  elecuyer [ Mon Mar 14, 2005 1:59 pm ]
Post subject:  Historic USGS Maps

While we don't have the Aerial Photos from the 1940s, we have a substantial collection of USGS maps available at:
http://historical.maptech.com

We recently added a pile of maps in Virginia and are always looking to expand the collection as volunteers come forward with additional maps.

-Ed Lecuyer

Author:  steaminfo [ Mon Mar 14, 2005 5:14 pm ]
Post subject:  Re: Aerial mapping information

Frisco1522 wrote:
Does anyone know of a site where old aerial photos from USGS are accessible? I'm talking 30s-40s, etc. I think the whole country was photographed around 1940 for map purposes.
I've looked around the net with no luck so far.
It would be dynamite to look at our favorite yards or roundhouses from that long ago.


That whole collection of aerial photos was provided to the County Recorders (Registrar of Titles or Register of Deeds in some states) of each county photographed. While many counties have more recent photos there's a fair chance the the late 40's early 50's photos are still gathering dust. (I know they are in my home county, my dad was the County Record from 1947 to 1980 or so.

Regards,
Doug

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