output to vectorized formats, e.g. pdf sometimes don't show the flightpath line

[Isabell Krisch]

When saving a topview to a pdf file, the flightpath vanishes. Saving the same topview to png keeps the flightpath.

[Reimar Bauer]

@isabell_krisch can you provide the flightpath?

with the builtin server / data I can't reproduce this

[Reimar Bauer]

Got the flightpath bei PM, but can't reproduce this. Can you still reproduce this?

[Joern Ungermann]

I cannot reproduce the problem either. @isabell_krisch , can you provide a more accurate description for reproducing the error? If I immediately save the Topview after starting the program, the PNG and PDF both are identical and show the flight pathg.

[Isabell Krisch]

@ReimarBauer @joernu76: Flight path only vanishes when saving with atmospheric data (for example cloud cover). The error is reproducible both with Python 3.6.6 and Python 2.7.14 and both times mss 1.7.3. I further tried different Webmap Services (including internal ones and EUMETSAT) and the problem is persistent.

[Reimar Bauer]

@isabell_krisch I used https://eumetview.eumetsat.int/geoserver/wms and tried with msg_fog | meteosat:msg_fog

in a completly fresh miniconda3 and only netcdf4 is downgraded to 1.4.0

I guess I understand now what you have found! issue_pdf_output.png

The connecting line between the points is not printed.

[Reimar Bauer]

All vectorized formats have the same issue

• svg
• eps, ps
• pdf

[Reimar Bauer]

The issue is related to the matplotlib.backends.backend_pdf.FigureCanvasPdf

From the ToDo there

# TODOs:
#
# * encoding of fonts, including mathtext fonts and unicode support
# * TTF support has lots of small TODOs, e.g., how do you know if a font
#   is serif/sans-serif, or symbolic/non-symbolic?
# * draw_markers, draw_line_collection, etc.

[Reimar Bauer]

looks like one solution may be we have to refactor self.line = self.ax.plot to become self.line = self.ax.scatter

scatter elements are visible in pdf too

https://bitbucket.org/wxmetvis/mss/src/3e8aaf3f55ea00e01c03210c07f032cbebd87066/mslib/msui/mpl_pathinteractor.py?at=stable&fileviewer=file-view-default#mpl_pathinteractor.py-395

[Reimar Bauer]

Because of API change we have to solve this in 1.8

[Reimar Bauer]

this needs upstream an improvement