Removal of all but selected colors

[krummelt1]

Hello everyone

Let me start by saying my editing ability is minimal at best.  Big thanks to anyone who helps a rookie out.  Hopefully this stuff is easy for y'all out there.

I am trying to take a JPG of a trail map and extract everything with the exception of the Trail and lift lines.  So far I have used "Selection by Color Select" and then been able to extract a majority of the lines.  This is where I run into a few problems that I feel like some better knowledge of the GIMP tools would help.  So here are the problems I am wrestling with.

1.  The color select also grabs a lot of random pixels of the same color resulting in dots all over.  Is there some way to filter these out?

2.  The lines it does grab are pretty good but on the edges where the lines might have a SLIGHTLY different color , those lines get fuzzy.  Is there some sort of automated process I can use to make the lines that were grabbed more consistent and more bold (like the example)?

I can't post my current progress at the moment but I was hoping to get the discussion started.

Thanks so much for the help.

TJ

[denzjos]

Do you have the original track file (GPX, GDB, etc) or is it a copy from a picture ?

[denzjos]

Maybe this can help you : https://www.gimp-forum.net/Thread-Separa...+decompose

I first used the curves to sharpen the picture and then make a copy from the result and used the multiply layer mode to darken the lines (and flatten the image). Then I used the plugin and clean the result with : GMic-Qr / Repair / Despeckle .

Result of the green lines : 

   

Then smooth with GMic-Qt / Repair / Smooth (Antialias)

     

There are still some imperfections but you can solve that with the gimp tools

[krummelt1]

(09-22-2020, 01:57 AM)krummelt1 Wrote: Hello everyone

Let me start by saying my editing ability is minimal at best.  Big thanks to anyone who helps a rookie out.  Hopefully this stuff is easy for y'all out there.

I am trying to take a JPG of a trail map and extract everything with the exception of the Trail and lift lines.  So far I have used "Selection by Color Select" and then been able to extract a majority of the lines.  This is where I run into a few problems that I feel like some better knowledge of the GIMP tools would help.  So here are the problems I am wrestling with.

1.  The color select also grabs a lot of random pixels of the same color resulting in dots all over.  Is there some way to filter these out?

2.  The lines it does grab are pretty good but on the edges where the lines might have a SLIGHTLY different color , those lines get fuzzy.  Is there some sort of automated process I can use to make the lines that were grabbed more consistent and more bold (like the example)?

I can't post my current progress at the moment but I was hoping to get the discussion started.

Thanks so much for the help.

TJ

Do you have the original track file (GPX, GDB, etc) or is it a copy from a picture ?  I only have a JPG of the mountain