Articles

How-to run QGIS 2 and QGIS 3 at the same time in Archlinux or Manjaro

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Since QGIS 3 was released, it's a nice and very pleasant upgrade. Unfortunately some plugins I use does still not work with Qgis 3 due to python upgrade from version 2 to 3.
It's possible to upgrade with tools like 2to3 (If interested, I suggest to watch Heikki Vesanto blog : https://gisforthought.com/updating-a-plugin-from-qgis-2-to-qgis-3/ ) but some plugins needs time to debug.

That's why, it's interesting during migration to have Qgis 2 and 3 at the same time in one computer. It's also possible to run Qgis 2 and 3 at the same time due to profile migration. They are not sharing same preferences folder so you are not breaking anything.
It's possible to have Qgis 2 and 3 running at the time with different way like Conda or Docker. But it's lightest to run it natively.

Archlinux/Manjaro is the Linux distribution I use. It have in my opinion a powerfull little thing called AUR (Arch User Repository) which automate installation of software. Furthermore, if y…

Resume script back from hibernation with systemd for wifi problem

I wrote a simple article which I found in my own opinion usefull ! I still need user manual when I use systemd and I still remember init.d command :-/

Since systemd, I am in an annoying situation when my desktop computer come back from hibernation :
- Network is unresponsive, Network Manager icon on mate desktop show a disable network,
- Command line on desktop and tty are working but you could send a command but never get this command sending to system. It's like freezing but system is still here !

The only workaround in a first time is to detach my TP-LINK TL-WN722N and to reconnect it. No error message in logs about chipset of this usb wifi device which is from Atheros and uses ath9k driver.

Next step to debug is to simulate behaviour but the only thing what I can do is disable ath9k driver before hibernation and renabling them after resume.
For those how wanted to know commands are like that :
Before hibernation disable modules :
rmmod ath9k_htc
rmmod ath9k_common
rmmod ath9k_hw
rm…

My GIS performance impact of Meltdown and Spectre patches

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When I saw performance regression few days ago of Meltdown and Spectre patch from cpu conception problem, I would like to perform some basic test to understand if it could slow down my process.

For those who don't know, here : a postgres article about performance regression : https://www.postgresql.org/message-id/20180102222354.qikjmf7dvnjgbkxe@alap3.anarazel.de 
Since some users finished to make benchmark with Meltdown and Spectre patch, I will not test it on my computer.

How to test  ?
First, I tested it on Archlinux based distribution named Manjaro Linux.


To know if patch is applied to my kernel, I just run this command :

$ cat /proc/cpuinfo | grep cpu_insecure Which reports this :

bugs        : cpu_insecure
bugs        : cpu_insecure
bugs        : cpu_insecure
bugs        : cpu_insecure
bugs        : cpu_insecure
bugs        : cpu_insecure
bugs        : cpu_insecure
bugs        : cpu_insecure When showing cpu_insecure, you know that KPTI patch is enable.

Then there is a specific C code…

Installation de Micmac avec support CUDA sous Archlinux

L'installation de Micmac sous Archlinux n'est pas des plus simples. Alors lorsqu'on veut ajouter le support CUDA, là ça se corse !

Voici donc un petit billet qui résume l'installation de Micmac sou sArchlinux avec le support CUDA

Auparavant il convient de tester l'installation de CUDA.
En ce moment nous sommes avec gcc6 et il y a beaucoup de problèmes sur les compilations notamment pour le CUDA https://wiki.archlinux.org/index.php/GPGPU#CUDA

Donc à la date où j'écris, pour avoir un cuda opérationnel, il faut installer une version de gcc antérieure. Il est possible de le faire avec le dépôt AUR (Archlinux User Repository). Il existe d'ailleurs un package Micmac mais qui n'est pas fonctionnel, il repose sur une ancienne version et ne supporte pas le CUDA

Exemple chez moi j'ai installé gcc5 :
yaourt -S gcc5 puis il faut faire un lien symbolique pour que ce soit pris en compte par CUDA (bien entendu, il faudra installer cuda avant avec pacman -S cuda)…

Adding Microsoft SQL server support in Qgis with Archlinux

Yesterday, I want to connect to a MSSQL Server with GIS support through VPN network until I realize it doesn't work. I use a modifying qgis-ltr aur package.
I've got this error :
[unixODBC][Driver Manager]Can't open lib 'FreeTDS' : file not found QODBC3: Incapable d'établir une connexion
If you want make it works, you have to add unixodbc and freetds packages. You could add them with :

pacman -S unixodbc
pacman -S freetds
Just edit this file :
/etc/odbcinst.ini
And add this

[FreeTDS]
Description = ODBC for FreeTds
Driver      = /usr/lib/libtdsodbc.so.0
Setup       = /usr/lib/libtdsodbc.so.0  Then just add a MSSQL layer in Qgis and it should work

Install GDAL ECW Support in Archlinux / Manjaro

---- ENGLISH VERSION ---- French version is below


Hi,


A quick note to install ecw support for gdal under Archlinux / Manjaro.
It's very simply to install software under Archlinux base, more than Ubuntu ou Mac Osx.

1) Install ecw :
yaourt -Syua libecwj2 These command install ecw lib revision 3.3. A quick search with find or locate show that  libNCSEcw.so is in /usr/lib/ It's a very important fact to install gdal later.

2) Gdal installation
It's common to install gdal with pacman but you cannot edit the PKGBUILD. So I recommand to use gdal-filegdb in AUR repository. This package does not include only gdb support but also other plugins like openjpeg and others.

 yaourt -Syua gdal-filegdb During the install, the process requires you to edit PKGBUILD. You have to choose yes and add this option to the build :
--with-ecw=/usr Validate and let the build ends

3) Verifying :
gdalinfo --formats | grep ECW
ECW -raster- (rw): ERDAS Compressed Wavelets (SDK 3.x)JP2ECW -raster,vector- (rw+v): ER…

MacPorts break my GRASS GIS 7.0 Yosemite installation

After installing the proper version of Python for running BlenderGIS, I would run a previous GRASS GIS Project but unfortunately It didn't want to launch !
I've got this common error :
arch: posix_spawnp: /opt/local/bin/pythonw2.7: Bad CPU type in executable
Well, I decided to make a new installation of GRASS GIS 7.0 by downloading it again from the official site : http://grassmac.wikidot.com/downloads ... After waiting a few moment with my poor internet connection, my bad, the same error is present !
With my favourite search engine, I explore the web and found some things like in the official documentation ( https://grasswiki.osgeo.org/wiki/MacOSX_GRASS_errors ) settings new python's environments variables. By the way, I put this in my ~/.bash_profile :
export GRASS_PYTHON=/usr/bin/python2.7export GRASS_PYTHONWX=/usr/bin/pythonw2.7
It's different to the official common MacOsX GRASS GIS errors but GRASS 7 require python2.7. This procedure didn't work. 
In the descripti…