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Author Topic: How to overlay GPX track on transparent PNG background?  (Read 894 times)

TrailJimmy

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How to overlay GPX track on transparent PNG background?
« on: March 13, 2020, 06:34:40 PM »
Hi, I have created a hiking track in caltopo. I would like to be able to take this track (ONLY the track, NOT the map) and overlay it on an transparent PNG background. I am NOT looking to make a map file to use on my GPS. I am working on a video project where I would like to overlay the track I created in caltopo over a a jpg image of something else. How can I do this?

jolly47roger

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Re: How to overlay GPX track on transparent PNG background?
« Reply #1 on: March 14, 2020, 01:09:02 AM »
The simplest way, I think, would be to open the track in GPSU, save the image then use Photoshop to select the track by its colour and then paste that onto the background.

Boyd

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Re: How to overlay GPX track on transparent PNG background?
« Reply #2 on: March 14, 2020, 03:16:09 AM »
What is Caltopo? Is it a Garmin map? If so, then can't you just open the track in Basecamp, take a screenshot and save it as a PNG file?

TrailJimmy

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Re: How to overlay GPX track on transparent PNG background?
« Reply #3 on: March 14, 2020, 04:17:44 PM »
The simplest way, I think, would be to open the track in GPSU, save the image then use Photoshop to select the track by its colour and then paste that onto the background.

Thank you for the suggestion. I downloaded GPSU, but unfortunately my track (actually several separate tracks) is very massive and GPSU was not able to open it, wayyy too many track points.  I'm sure there is a way to strip down the track to include fewer track points, but i don't know what the limits are of the free GPSU version are, and not willing to pay for an upgraded license for a one time use. To try and test if would work with the track points that GPSU did load, I went to go save it but not sure what to save it as if it's going to be opened in photoshop. There were like 100 different file extensions and none of them were image file types that I would expect photoshop to be able to open. Can you clarify how I would save the file in GPSU to work with photoshop?

What is Caltopo? Is it a Garmin map? If so, then can't you just open the track in Basecamp, take a screenshot and save it as a PNG file?

caltopo.com... the best mapping platform out there...

No.... like I said, not trying to capture a picture of my track with ANY map background. If that was the case I would just screenshot the map in caltopo. I want to overlay my track only over a different image that is NOT a map. Imagine this... you have a track of the Appalachian Trail, and you want to overlay that track over something like a cartoon style image of the united states.

jolly47roger

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Re: How to overlay GPX track on transparent PNG background?
« Reply #4 on: March 15, 2020, 12:03:29 AM »
Open the GPX in GPSU and click the map icon to draw the track.

Then File>Copy bitmap to put it on the clipboard

TrailJimmy

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Re: How to overlay GPX track on transparent PNG background?
« Reply #5 on: March 15, 2020, 05:57:28 PM »
Open the GPX in GPSU and click the map icon to draw the track.

Then File>Copy bitmap to put it on the clipboard

Thanks! That worked, with the section of the track that was loaded before I hit the track point limit. Are you aware of any utility where I can reduce the track points... by a percentage, or maybe a max number of track points per track?

jolly47roger

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Re: How to overlay GPX track on transparent PNG background?
« Reply #6 on: March 17, 2020, 04:35:52 AM »
If you select track summary, GPSU itself reveals tools to simplify and compress tracks