Duplicating lines to create Mag North line array

Timothy C's Avatar

Timothy C

13 Dec, 2016 10:17 PM

I'm using caltopo to create Orienteering maps for my Boy Scout troop, and so far it has been working great. For our purposes, it is very helpful to have magnetic north lines on the maps; I have made these by creating a bunch of bearing lines at 0deg mag, but this is pretty time consuming. (See the green lines on this map https://caltopo.com/p/325P for an example) I need the lines spaced about 2.5cm apart on the printed map, and I was wondering if there's any way I can use a custom layer or something like that to create these lines automatically.


  1. Support Staff 1 Posted by matt on 13 Dec, 2016 10:42 PM

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    Sorry, there's no easy option for this.

    With a pro subscription, you can specify custom images for each corner of a PDF. As a one time investment of effort, you could use photoshop or a similar program to create a transparent image with vertical black lines, and specify that as one of the corner images. The PDF is 200dpi, so you'd want to space the lines every 200px or so. Without a UTM or lat/long grid, the map portion of the page is 7.5x9.25in, so you'd want a 1500x1850 px image.

    It's not pretty but the best I can do. If you want to go that route I can give you a 2-week trial pro subscription to see if it will meet your needs or not.

  2. Support Staff 2 Posted by matt on 13 Dec, 2016 10:44 PM

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    Sorry, I just saw that was mag north not true north. The same technique would apply, assuming you're only creating maps for a limited area and you can re-use the same image without the declination changing noticeably.

  3. matt closed this discussion on 13 Dec, 2016 10:44 PM.

  4. Timothy C re-opened this discussion on 13 Dec, 2016 10:56 PM

  5. 3 Posted by Timothy C on 13 Dec, 2016 10:56 PM

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    Aren't mag north and magnetic north the same thing?

  6. Support Staff 4 Posted by matt on 13 Dec, 2016 11:01 PM

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    Yes, I typod the reply. Edited to say true right after I sent it.

  7. 5 Posted by Timothy C on 30 Dec, 2016 07:25 PM

    Timothy C's Avatar

    Sounds like my basic subscription will work for my needs, but thanks for the offer!

  8. Timothy C closed this discussion on 30 Dec, 2016 07:26 PM.

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