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Using an iPhone as a GPS for JOSM (on Windows)

If you wanna see your current position in JOSM (Java OpenStreetMap Editor), but your mobile computing device lacks a GPS chip, this could help:

You need:

an iOS device

enabled tethering

the GPS 2 IP app

installed JOSM

We're going to install gpsd (and cygwin, socat) on windows and connect it with your iOS device and JOSM.

First, download and install the GPS 2 IP app to your iOS device. Enable tethering, then open the app and use following settings:

NMEA messages to send:

GGA

RMC

Connection method: Socket

iPhone IP selection: Hotspot

Then, install cygwin: Download and run the setup-x86.exe and use the defaults until you reach the Select Packages step. (you'll have to use the 32 bit version, else you have to compile gpsd yourself)

Search for socat, open the Net category and mark it for installation with one click. Then continue with next. A lot of dependencies will be installed, too.

Now download the gpsd binaries from http://home.arcor.de/ulf.lamping/gpsd/gpsd.html (look for gpsd-2.37-1-win32-bin.zip). Extract the contents of that .zip directly into your cygwin\bin dir.

Open the cygwin terminal twice. In the first one, input

socat GOPEN:/dev/gps,ignoreeof TCP:172.20.10.1:11123

(where 172.20.10.1 is the IP displayed by the app).

In the second one, run

gpsd -n -N -D 1 /dev/gps

You can check if everything works correctly by opening a third cygwin terminal and typing gpspipe -w.

Now, open JOSM and install the LiveGPS plugin (Go to Edit > Preferences > Plugins and look for LiveGPS. Enable it, then close the window with OK. The plugin gets downloaded and JOSM restarts itself.

Enable the display of the gps status information panel by enabling Windows > LiveGPS. Then activate the gps position tracking with GPS > Capture GPS track. If everything works correctly, the status field in the panel should read Connected and a new Live GPS Layer should appear in your layer list.

Have fun :)

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Export Slides from Keynote with better embedded speaker notes

I'm using CPDF and pdflatex for that. For pdflatex you could use this docker image, so you don't have to setup a full latex environment.

First export your slides from keynote without speaker notes and in full quality. (slides.pdf)

Then export your slides with speaker notes and in lowest quality (we drop the slide images, so a smaller file is faster). (notes.pdf)

Cut the speaker notes from the combined slide with cpdf:

cpdf -mediabox "0 250pt 1080pt 125pt" slides-with-notes.pdf -o notes.pdf

You may have to play with the mediabox values to match the width and height of your notes.

Then use this ruby script (it's a modified version of this stackoverflow answer) to generate a .tex file for pdflatex.

#!/usr/bin/ruby latexhead = <<'EOF' \documentclass{article} \usepackage[pdftex]{graphicx} \usepackage[margin=0pt,paperwidth=1927pt,paperheight=1300pt]{geometry} \usepackage{pdfpages} \usepackage{morefloats} \begin{document} EOF latextail = <<'EOF' \end{document} EOF pages = %x[pdfinfo #{ARGV[0]}].split(/\n/).select{|x| x=~ /Pages:/}[0].split(/\s+/)[1].to_i puts latexhead s = (1..pages).to_a s.each do |p| puts "\\begin{figure}[!htbp]" puts "\\includegraphics[page=#{p}]{#{ARGV[0]}}" puts "\\includegraphics[page=#{p},scale=1.7]{#{ARGV[1]}}" puts "\\end{figure}" puts "\\clearpage" end puts latextail

Run the ruby script with the slides and notes pdf as arguments and feed the output to pdflatex.

ruby texgenerator.rb slides.pdf notes.pdf > embedded.tex pdflatex embedded.tex

Now look into embedded.pdf - it contains your slides in full width with the speaker notes below.

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Keeping your docker bridge alive

If you have postgres (or any other daemon) listening on your docker default bridge ip (172.17.42.1) and you are upgrading your packages regularly, it may be that your docker bridge is still down, but your service is already trying to bind to the bridges ip (and failing miserably).

I didn't find a way to manipulate APT so it restarts docker before postgres, so I had to look for other solutions.

One possible way is to persist the bridge docker is using:

On ubuntu install the bridge-utils package:

sudo apt-get install bridge-utils

Then stop your docker daemon and remove its bridge:

sudo service docker stop sudo ip link set dev docker0 down sudo brctl delbr docker0 sudo iptables -t nat -F POSTROUTING

Now open /etc/network/interfaces in your favourite editor and append the following block:

auto docker0 iface docker0 inet static address 172.17.42.1 netmask 255.255.0.0 bridge_ports dummy0 bridge_stp off bridge_fd 0

The bridge_ports dummy0 line is needed, else /etc/network/if-pre-up.d/bridge is ignoring our bridge. That causes some interface dummy0 does not exist! error messages, but you can safely ignore them.

bridge_stp off disables the STP protocol and bridge_fd 0 reduces the forwarding delay to zero - both things that keep a bridge thats only used locally happy.

Because we named the bridge docker0 docker is automatically using it. If you want to give it an other name, look at the -b option for DOCKER_OPTS.

Initialize the bridge by calling

sudo /etc/init.d/networking reload

and start your docker daemon again:

sudo service docker start

🌴

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