converser.nz

Category: NZTekonverse -> Qgis

  • Python Scripting [1C]: Scripting to copy map aerial layers 3

    So I spent a bit more time completing the script, which now looks like this: import glob import os import shutil import xml.etree.ElementTree as ET tree = ET.parse(‘/home/patrick/Sources/CopyFiles/Source/layers.qlr’) root = tree.getroot() for layer in root.iter(‘layer-tree-layer’):         sourcename = layer.get(‘name’)         print(“Layer: ” + sourcename)         sourcepath = “/home/patrick/Sources/CopyFiles/Source/” + sourcename + “.*”         #print(fpath)        …

  • Python Scripting [1B]: Scripting to copy map aerial layers 2

    So as I said at the end of the last post, I am learning to script in Python. Which is turning out to be breathtakingly simple and easy to do. I remember that I was going to do this script originally in Python then ended up doing it in Powershell. Why I did that at…

  • Python Scripting [1A]: Scripting to copy map aerial layers 1

    In my arsenal of computers I have one low spec one that still runs Windows. Even with all the stuff I have for Linux, there are still a handful of tasks that use Windows only software, although this has diminished to the point that this computer often doesn’t get turned on for weeks at a…

  • Computing resources optimisation [2B]

    Last time I wrote a post in this series it was looking at upgrading some of the hardware that I have. This time it is looking at task separation, or in another way, using mediapc to do some stuff like I have looked at previously. This keeps coming up because I have four computers and…

  • Qgis functions for labels

    One of the great things about Qgis is being able to use expressions in a range of things. This is just a little bit about using a function to combine various fields together to make a caption on a label of a feature. In NZ Rail Maps I have features called Locations which are a…

  • Computing resources optimisation [2A]

    So after a couple of months ago when I did some resource optimisation with my existing computers, it’s time to look at the next stage. That stage will be upgrades to enable all four computers to be used for the most stuff they can. The plan I am considering at the moment (subject to resourcing)…

  • Graphics issues with map mosaics [3]

    Continuing from the previous post in this series. Once you have made up some mosaic tiles you need to know how to edit the sidecar files. In this case with the map tiles that come from LDS there are three sidecar files alongside the actual image. We only need to concern ourselves here with the…

  • Graphics issues with map mosaics [2]

    As I wrote in my last post there are problems when you have to scale down imagery significantly. So I am working on a new map mosaic experiment to see what I can do with it. Starting from four tiles at 0.4 metre resolution i.e. 1 pixel measures 0.4 metres on one side, I am…

  • Graphics issues with map mosaics [1]

    Well this is a tricky little number for people like me who are doing things with high resolution images. I am frequently combining high resolution scanned Retrolens stuff with other aerial images and running into some scaling issues. Basically if I have got a Retrolens image at a certain resolution and I have the aerial…

  • Limits.conf settings to allow a lot of file handles

    One of the things I always have to remember to do for Qgis is for each time I install a computer or VM is to change the default settings in /etc/security/limits.conf to allow a larger number of file handles. Otherwise Qgis can’t open a lot of layers at once. Open this file and put the…