Sunday, December 6, 2015

PDF Improvements

CalTopo PDFs are now sporting a couple of improvements.

The most noticeable of those is a title input field on the print page:

If filled out, it will show up in a couple places.  On the bottom of the PDF itself:

on the account dialog:

and also in Avenza PDF Maps:

Slightly less noticeable is an improvement in label positioning.  Before, labels were drawn without regard to each other; on a busy map, this resulted in an unreadable mess.  Now, labels will not draw on top of each other.  If two labels conflict, the PDF generator will attempt to move them around (to only few positions; it's not very smart yet), and if that doesn't solve the problem, it will omit the second label to improve readability.

Label 2 automatically floated to the left to avoid conflicts.

Finally, although hard to demonstrate on a screen, MapBuilder layers will now print better.  To create high resolution PDFs, CalTopo starts with a large image and then shrinks it down to fit the page.  With layers that look the same at all zoom levels, like USGS map scans, this works great.  With layers that get redrawn at each zoom level, like OpenStreetMap, shrinks all the lines and text down to the point where they're hard to read.

When you print a MapBuilder layer, the PDF generator will request a tile that's been scaled up by a custom amount so that lines weights and text will come out looking right.  This is only possible on layers produced in-house, but at some point I may ramp up an OpenStreetMap server so that I can do the same thing with OSM maps.

1:24k PDF created without scaling

1:24k PDF with scaling


  1. Nice, I noticed on MapBuilder you also now allow the users to display, if they choose to, the distance between two nodes. It would be great if you would similarly give the option of choosing if you want to display the mane of the trails (if available). Right now it always display the name (again when available) but sometimes the user may want to keep their maps "more minimalist". Cheers and keep up your great work.

  2. In my humble opinion the text on the contour lines is a bit overpowering with the new resizing you have implemented. Any map drawn at larger than 63K scale (I know this is large scale, but nice for "big picture" of a route) is a "soup of characters" from the contour lines labels. You may want to consider changing the color of the contour lines labels or reduce their size/frequency?.

    1. It may not be perfect at all zoom levels, but I deployed a fix that should greatly improve this.

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  4. When creating a geospatial PDF using, for use in the Avenza PDF Maps app, what is the largest area the map can cover, without losing resolution, details, etc.?

    What print settings should I use? (paper size, etc.)