old 1903 topo map bldg locations on modern maps

[maxxkatt]

I noticed with using historic aerials maps and overlays the present day location old buildings and roads are about 350 feet east of the modern topo maps.

why is there a difference and is there a way to locate an old home site on the 1903 topo map with the present day topo map or aerial photo?

 

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[Tom_in_CA]

You're right: When you switch back and forth from the old topos, to the new topos (or satellite), there is often variation of fixed objects. Wish I had an answer for you. But the accuracy is still usually good enough, that you can hone down the spread-of-iron, when trying to find an old site.

 

[1320]

I noticed with using historic aerials maps and overlays the present day location old buildings and roads are about 350 feet east of the modern topo maps.

why is there a difference and is there a way to locate an old home site on the 1903 topo map with the present day topo map or aerial photo?

When using overlays, you have to get the size as close as possible....it's hard to do but worth the time that it takes. The overlay map is not the same scale as the topo maps/aerials.

If the house site is rural, it likely won't show up on any topo map. Aerial images are dependable but I've never tried to use one with an overlay.

 

[Chadeaux]

With the addiction to "ground truthing" old maps to Google Earth in my list of habits, find 3 points of reference that are definitely shown on both maps and mark them. Usually road intersections are the best way, or other land marks that are not likely to have moved (yes, roads are moved, but you should easily be able to determine where that has happened and use another intersection).

Using a photo editor, overlay one above the other (must use transparency - which is adjustable) align the points (resize and rotate as needed). I usually place the newer map on the bottom layer at 0 transparency, and place the old map above at about 80% transparency (or 20% visibility ... varies with paint programs).

Now. after you have aligned the maps as close as possible, create a third layer. You can do your markup of your locations of interest on the third layer. Just put marks on the top layer (I like to use a dot - size relative to the area).

Now, make the old map layer invisible, the modern map fully visible (no transparency) and adjust the transparency of the layer you marked up so that you can see your marks, but not obscure the area belos. Now print out the results. Your new map will now have all of your locations you wanted to search on the old map placed on the new map.

Not as easy as guessing, but probably more accurate. If accuracy isn't important, you probably wouldn't have asked.

 

[angelito1]

Great info chadeaux, do you know of any good topo map apps for Android? .... Thanks

 

[Chadeaux]

Topo is topo ... they're image files. If you can see that particular image on your android, you have it. If you can't you don't.

Never have seen (although I'm sure there are some) a photo editor for android that will do what I described. There likely are some for apple's Incompatible-Pad however.

Mobile devices are nice for convenience, but mostly worthless if you need to do detailed work.

I do web design, photo editing, create e-books and other publications --- all designed to be used by mobile devices, however, without a COMPUTER it would NEVER happen.

Android aps are mostly designed on computers using special "emulators" because (it is my understanding) you can't develop mobile aps or anything else much in a mobile environment.

 

[Truth]

Would you say Topo is the best at overlaying map?


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