Google Maps currently doesn't include a method to copy/move features between maps, however as you can import and export features using KML files you can easily use this to achieve this task.
Restrictions and Gotchas to Keep in Mind
If your map uses the 'Snap To Roads' feature that allows lines to follow roads, then this trick is slightly more complex.
When copying a 'Snap to Roads' line, it is changed to a standard line.
So before trying the trick below, in the source map, disable this feature by right clicking every line in turn and turning off the snap feature. Then Save the map, and copy as below. Then in the destination map afterwards will need to re-enable the feature.
'Search Results' - Results saved to "My Maps" via the 'Save to' feature - only export the title, not the description so such results will not show on the new duplicate map .
NOTE: There is a 3Mb limit on displaying KML via Google Maps. So if your map is particularly large - in other words, lots points or description, then there is a chance your copy will silently fail. No error message is shown, it just fails.
1. First job is to get a KML link for the source map
View the source Map, and right click the KML link and copy the link to the clipboard (look for something like 'Copy Shortcut' - the exact wording depends on browser)
2. Then need to import that link into the destination map
Now you have the URL of a KML file in the clipboard, goto (or create) the destination map to copy the features to, and in Edit mode, click the Import link, and paste the url into the 'enter the url of map data on the web' box, and click Upload.
Be prepared to rename your map, as often the import will name the MyMap as per the file just imported.
Note: if you where wanting to 'move' features, after verifying they have copied ok, just delete them from the source map. This method copies ALL the features from the source map, so if only want to copy some of the features, just delete the unneeded ones from the source map.
NOTE: If you need help with KML (Keyhole Markup Language) files, jump over to the KML for Land Surveyors Group Hub and ask your questions there.
This Content Originally Published by a land surveyor to Land Surveyors United Network
very helpful for something I am working on.. thanks Jobber