Use Google Earth to align old maps
on the current environment
I happen to live in the middle of what used to be the old Camp Bowie in Fort Worth, Texas. It existed from about 1917-1918 and my house is setting on top of what used to be the machine gun batallion. I discovered this when I found an old map of the camp on the internet. The map was a little confusing because most of the streets that are here now weren't then. So I used Google Earth to align the old map to see exactly where everything was with a current perspective. This works great, especially if there are features on your old map that still exist so it is easier to register.
I already had the map in jpg format, but you could scan one from a paper copy and use that.
Open Google Earth and find the approximate location that you're researching. You can type in a city name and pin point from there or use an address if there is one. You may have to zoom and scroll around to find it. Look at the old map for distinct land shapes and patterns or geographic features that your eye might connect with the Google Earth terrain. When you see a pattern or feature that is on both Google Earth and the old map you can then overlay the old map and line it up.
If you know a city or address that is close to the area you're interested in type it into the "fly to box" in the upper left. Alternatively you can zoom and scroll the globe until you find the area.
Here I've located and zoomed to the approximate area and by doing a visual scan, I can see a unique feature, the 5 point intersection that makes a distinct triangle pattern.
This was a good visual match as you can see in the old map below; some of the roads that form the triangle were there in 1917.
Now that I have a match reference on both maps, I can overlay the old map.
Click on either the overlay image icon above the map or the dropdown Add menu. The New Image Dialogue Box pops up and you can browse for the map image on your computer to load it.
Give the overlay a name and adjust the opacity so you can see the Google Earth features below it for registering.
After you save it you can re-open the adjustment dialogue box by finding your overlay under the Places tab then right clicking on it and open the Properties.
Use the center green plus shape to position the map. Use the green corners and side marks to scale and the green diamond to rotate.
This can be a little tricky, especially the scaling. To keep it proportionate you will need to play with it to get it lined up as much as possible. Just keep an eye on all of the features that show on both maps and get them registered. If possible find matching features at the far left and right or top and bottom to keep the scale correct.
Here I have the old map lined up with the current aerial. I can now see all of the new roads and houses in relative position to where
the fort was. This is a very handy way to pinpoint your next metal detecting hunt.
Hope it helps find your next treasure!
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If you don't have Google Earth you can get it here