Curious about GPS map overlay possibilities

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Glennielondon

3 posts

Wannabe Geek

#243815 3-Jan-2019 12:47

Hello all, I am curious as to if it is possible to somehow have an enable GPS overlay on a downloaded map. More specifically what I have going on is this, I have a depth chart map of a local pond I ice fish on frequently. I am attempting to somehow get a GPS overlay on this depth chart map so I would be able to tell where the river channel ran through, or where the deepest points are and be able to tell where they are from my location. The map is at this site http://www.fishweb.com/maps/alcona/alcona_dam_pond/index.html and I have also included the map in the attachments. I'm not sure if this is even possible but I would love to be able to find a way to do this or to somehow overlay the image onto some type of current software.

nickb800

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#2153861 3-Jan-2019 14:12

Yes that's doable.

Probably lots of specialist software out there that would do exactly that, but I from the top of my head I'd suggest:

1) Add to Google Earth (desktop) as an 'Image overlay'. There is a calibration process called 'georeferencing' which makes sure the features on the map line up to their actual coordinates

2) Trace over the features that you are interested in, as a 'Path' (line) or 'Polygon' (blob)

3) Save the path/polygons as a kml/kmz file, and upload to Google My Maps

4) Open Google Maps on your mobile, go to 'My places' and find the map that you've just uploaded

Glennielondon

3 posts

Wannabe Geek

#2153893 3-Jan-2019 14:53

I have gotten as far as tracing the area after I already stretched the image over google earth, however when I save the path and try to upload it to my places, only the path outline goes and not the content inside the path, what am I doing wrong?

nickb800

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#2153922 3-Jan-2019 15:49

What do you mean by content within the path? Only the path itself will come across

Glennielondon

3 posts

Wannabe Geek

#2153931 3-Jan-2019 15:56

What I meant is that when I save the file, after tracing a path around the content I want to view with a GPS, when I go to google maps and create a map and upload the file of the path I saved, only the outline of the path is loaded onto the google map, nothing within it. I believe I am doing something wrong. I am saving the path by right clicking on the layer within earth and saving it as a place. I also attempted to save the layer of the image in which I was overlaying onto earth, however when I save and attempt to upload that image to google images, it doesn’t appear to make a change and tells me that “one object in a row can’t be shown” or something along those lines.

frankv

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#2153974 3-Jan-2019 17:05

That map is a GIF, so you have to go though the georeferencing process, and "trace" the lines you want into Google Earth.

I'd look around (e.g. at Michigan's mapping agency) for a map of your river; I'd guess that something in the 1:50,000 or 1:63360 or better should have enough detail. Hopefully you can download it in .KML or .KMZ format. If not, there's lots of mapping app (e.g. OpenJump) that can read in other formats (Shapefile is pretty ubiquitous) and output KML or KMZ. Download the app, download the map, load the map, prune out the part you don't want, export to KMZ.

arkolos

1 post

Wannabe Geek

#2612102 28-Nov-2020 01:06

Hello. There is a new app called "You are here" that allows this : having the GPS position on any map. It's only available for Android for now. https://play.google.com/store/apps/details?id=com.you_are_here