ClemRz

Advent of Code - challenge 2015

ClemRz

Nearsoft Code Challenge 2017

Challenge: https://www.hackerrank.com/contests/ns-code-challenges/challenges

• Day 1 puzzle
• Day 2 puzzle
• Day 3 puzzle
• Day 4 puzzle
• Day 5 puzzle

Day 1 puzzle

ClemRz

Ible Sort

This Gist shows how to quickly sort the Instructables entries in a contest.

How to

First you need to know the Contest ID. Follow the steps:

• Open the developper tools of your browser and navigate to the contest page
• in the network tab search for getContestEntries.json

ClemRz

Convert GPS files for Navilink (Locosys BGT-31 GPS)

This is how you convert GPX files (or any other file) to fit for the Navilink software / Locosys BGT-31 GPS.

Convert a GPX file to a waypoint file (OziExplorer format: wpt)

Install GPSBabel then run the following in your terminal:

gpsbabel -i gpx -f your-input-file-name.gpx -o ozi -F your-waypoint-file-name

ClemRz

How to synchronise your photos with a GPS track

Install ExifTool and run the following in a terminal:

exiftool -geotag="/path/to/your/GPS/track.kml" -geosync=7:00:00 /path/to/your/photos/folder

The geosync parameter is used when your GPS track is not in the same timezone as your photos. In the above example the GPS track is in the UTC timezone while the photos are in UTC-7.

ClemRz

Filter a KML by HDOP value

Sometimes a trace KML file obtained from a GPS has some points with high HDOP value. Those are usually not accurate and can be omitted from the trace.

How to use this script

Then open a terminal and run:

python zFilterByHdop.py /path/to/your/file.kml

ClemRz

How to override a class in C++ in an Arduino environment

I was working on a custom firmware for ESP8266 using the famous Arduino library and I wanted to create a websocket server. I also wanted the EPS to serve the web page that acts as a websocket server (having the ESP in AP mode).

The awesome library ArduinoWebSockets is very easy to set up and make the ESP serve websockets connections on port 81. The thing is that when I was opening a browser at http://192.168.4.1:81 I had this message: "This is a Websocket server only!". Wow! This means that ESP is capable of returning a http message to the browser! This also means that the message could be tweaked to include the actual html page with the websocket JS client!

I looked at the library file WebSocketsServer.h and found that the method handleNonWebsocketConnection was the one sending this message.

ClemRz

How to pass a callback function as an argument (Arduino, C++)

Arduino Uno:

bool myCallback(int value) {
  // here your custom logic
  return status;
}

ClemRz

How to add vectorial PALSAR-2 Global Forest data in QGIS

Follow those simple steps:

1. Go to http://www.eorc.jaxa.jp/ALOS/en/palsar_fnf/data/index.htm and select latest FNF map.
2. Select the region and sub-region
3. Download the FNF file
4. In your QGIS project open the file that has no extension
5. If you need to merge several FNF files, save them first as GTIFF (raster) and use the merge tool in the raster menu
6. In the raster menu select Conversion > Polygonize, remember to check the "field name" checkbox

ClemRz

How to import OSM vectorial data into QGIS

Follow the steps:

1. Go to https://www.openstreetmap.org and log in
2. On the right, open the layer menu and check the public GPS trace
3. On the top-left corner click on "Export"
4. Enter the coordinates
5. Click on Export button
6. Open the file with a text editor