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Looking For Easy Way To Do Map Overlays


Steve_Colby
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Does anyone have any suggestions for doing quick and easy map overlays? For instance, overlaying a USGS Map over a Google Satellite image? I would think there would HAVE to be an easier way than creating images of both maps and then laying a transparency of one over the other.

 

Thanks for your suggestions.

 

~ Steve

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Does anyone have any suggestions for doing quick and easy map overlays? For instance, overlaying a USGS Map over a Google Satellite image? I would think there would HAVE to be an easier way than creating images of both maps and then laying a transparency of one over the other.

 

Thanks for your suggestions.

 

~ Steve

Steve,

 

It is easy to do overlays in Google Earth. I haven't done it in a couple of months so I'm rusty and may miss a step in describing the process, but basically it is as follows.

 

Scan the map you want to use, or get a digital copy off the internet. Make it an overlay by clicking the Add Overlay button on Goggle Earth. You can them adjust the transparency level of the overlay so you can see through it to the underlying Google Earth Map. Reduce 3D as it will distort the overlay.

 

(I should note, as you must already know , that USGS maps of the northeast and much of the west are already available in the form of overlays on Google earth, and are alredy positioned for use.)

 

The difficult task is to get the overlay and the underlying GE map to line up. The easiest task occurs when the overlay has sections, townships and ranges. There is a service that I use (www.Earthpoint.us) that puts section lines on the Google Earth map, making it easy to accurately resize the overlay to the GE map. (The overlay has handles that allow stretching the image to fit).

 

If you don't have section lines, it means you have to match map features, which may be more difficult, but still very doable (use three known points on each and stretch till they overlay).

 

That is the quick and dirty of it. That works if you are doing it for yourself. If you want a copy others can see and understand, it gets more difficult because two images that use similar colors with semi transparency don't stand out from one another when they are combined.

 

What you want then is a high contrast overlay that will show up distantly on the underlying Google Earth map. Without getting into excruciating detail (I'll answer questions if you want) I manipulate the overlay in a photo editing program and convert the background of the image (the part I don't want to show) to transparent in a transparent GIF file. I convert everything I want to show to a bright color. When I overlay the transparent GIF on Google Earth, the background of the overlaid map is transparent and the map features show in bright contrast on the Google Earth base.

 

It may all sound a bit complicated, but it isn't and once you have done it a couple of times, its like riding a bike.

 

Maybe that will be of use, and I will happily answer questions.

 

Dave

 

Keep the Show on the Road!

 

PS Mobilene, Sit Properly, and others here may have better work flows.

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Steve,

 

It is easy to do overlays in Google Earth. I haven't done it in a couple of months so I'm rusty and may miss a step in describing the process, but basically it is as follows.

 

Scan the map you want to use, or get a digital copy off the internet. Make it an overlay by clicking the Add Overlay button on Goggle Earth. You can them adjust the transparency level of the overlay so you can see through it to the underlying Google Earth Map. Reduce 3D as it will distort the overlay.

 

(I should note, as you must already know , that USGS maps of the northeast and much of the west are already available in the form of overlays on Google earth, and are alredy positioned for use.)

 

The difficult task is to get the overlay and the underlying GE map to line up. The easiest task occurs when the overlay has sections, townships and ranges. There is a service that I use (www.Earthpoint.us) that puts section lines on the Google Earth map, making it easy to accurately resize the overlay to the GE map. (The overlay has handles that allow stretching the image to fit).

 

If you don't have section lines, it means you have to match map features, which may be more difficult, but still very doable (use three known points on each and stretch till they overlay).

 

That is the quick and dirty of it. That works if you are doing it for yourself. If you want a copy others can see and understand, it gets more difficult because two images that use similar colors with semi transparency don't stand out from one another when they are combined.

 

What you want then is a high contrast overlay that will show up distantly on the underlying Google Earth map. Without getting into excruciating detail (I'll answer questions if you want) I manipulate the overlay in a photo editing program and convert the background of the image (the part I don't want to show) to transparent in a transparent GIF file. I convert everything I want to show to a bright color. When I overlay the transparent GIF on Google Earth, the background of the overlaid map is transparent and the map features show in bright contrast on the Google Earth base.

 

It may all sound a bit complicated, but it isn't and once you have done it a couple of times, its like riding a bike.

 

Maybe that will be of use, and I will happily answer questions.

 

Dave

 

Keep the Show on the Road!

 

PS Mobilene, Sit Properly, and others here may have better work flows.

 

A few other comments about matching old and new maps. There will be self evident to anyone who does this regularly, as yourself, but might help the less experienced.

 

Old maps, and by that I mean any not based on aerial or satellite images, are not likely to be spot on. Those based on original Land Office surveys will vary in quality based on the surveyor, how much detail he included, and how many guesses he allowed himself. I find them usually pretty good along section lines because he had to walk them, but within sections, it was often a guess.

 

USGS maps are better where they are available in historic form.

 

Road maps are diagrammatic, even those done carefully like the auto club strip maps of the teens and 20's. None the less, I find them amazingly good, given the means they used (compass, odometer).

 

Of you overlay a well done strip map onto Google Earth you will be disappointed that they don't usually line up very well. But they do fit better locally. What I mean by that is that locations at opposite ends of the strip map will be displaced in distance and angle because of accumulated small errors. But locally they will line up pretty well. The shape of a road (curves, turns) may be the best indicator when trying to match old and new. Twisting and turning the overlay may produce a fit.

 

I have great praise for the Google Earth overlay feature. It is an amazing tool for discovery. For example, I was messing with a 1916 USGS map that included the area where we live. When I did the overlay, there was a house showing on the acreage next to us, which is now vacant land. A quick walk determined that there was spring where the house stood, I had no idea there hand been a house or spring there.

 

Without the Google Earth overlay, Sit Properly (Eric) and I would have never found Spencer. We would have wandered hundreds of yards off track.

 

Love those overlays, and let me know how I can help!!

 

Dave

 

Keep the Show on the Road!

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Dave,

I never knew the Google Map Overlays existed. I use the regular Google Map service and there is no "Overlay" button. It was only after reading your post that I found Google Map Maker. I going to have to learn this whole thing... And as I get older, it seems to be more complicated to do so. :blink:

 

Steve

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Dave,

I never knew the Google Map Overlays existed. I use the regular Google Map service and there is no "Overlay" button. It was only after reading your post that I found Google Map Maker. I going to have to learn this whole thing... And as I get older, it seems to be more complicated to do so. :blink:

 

Steve

 

Steve,

I was describing GOOGLE EARTH, not GOOGLE MAP MAKER. Google Earth works great for overlays, but I see that Google Map Maker has an overlay feature I will need to explore!

 

I know Google Earth works for what you want to do (match old and new maps), but I sort of doubt that Google Map Maker has some of the needed features (eg section lines). I get the impression Google Map maker is a useful tool for drawing maps.....which for me would be a big asset, but one I didn't know existed!!! So we are even!! Oh Boy, more tools to learn.

 

Dave

 

Keep the Show on the Road!!

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