It’s been a while, since I last developed things for qgis2web. To be honest: I lost focus on the whole project after we decided to merge qgis2leaf with the openlayers exporter back in 2015. Tom Chadwin and many others did a great job and managed to develop the state of-the-art plugin when it comes to publishing content right from within QGIS. But as I was lucky I had the chance to develop some interesting things for QGIS2web in the last weeks.
The ArcGIS REST API provides some interesting endpoints which can be used for free with a developer account. But how to do this in QGIS as you might not have a licensed ArcGIS Desktop license at hand: A short example using isochrones or “service areas” as Esri calls them.
The last days I needed to work with other geoenthusiasts on a PostGIS database. Unfortunately, as you upload a layer from QGIS you will be the owner of the new created table and no one is able to alter it by default. Here I show you, how to change this using some “trigger functions” and some shared roles.
When using QGIS along with PostGIS you might want to publish data directly from inside QGIS into your PostGIS database. This is not only convenient as you don’t need to change the software of use but also easier as it only takes a drag and drop in QGIS instead of any commandline/fancytool. Yet it comes with a disadvantage: the number of inserts from QGIS into the db is limited to 200 per transaction. So it will take some time to insert a bigger dataset with 150.000 points or so. So how to overcome this?
The Copernicus Program provides an interesting alternative data source for your work with Landsat data… Sentinel images: Copernicus will deliver an unprecedented volume of free data, provide new operational services and foster new business opportunities and job creation. The data itself is collected since 2014 (Sentinel 1A) and the operation is scheduled to deliver data till 2020 at least. But how to get the data into the GIS of your choice.
On 24th of February, the QGIS developers have officially released QGIS 3 (codename “Girona”). It is the third major version of the free and open source cross-platform GIS software. In this post, I want to tease you with the most important infos and installation instructions.
Our author Riccardo recently published an article on GeoNet where he described the traffic aware analysis of service areas (isochrones) in ArcGIS Pro with the analytical support of ArcGIS Online. I searched for a way to do something similar in QGIS. So let’s follow the white rabbit.
Donut Polygons were the nightmare in first GIS courses. At the very moment I can’t remember why but the concept of an inner and an outer part makes total sense in the real world (house with a patio, lakes with islands, Rome with the Vatican City) yet the creation of those was never the covered in the basic “how to edit”-classes. So how can we create them with QGIS, ArcMap as well as ArcGIS Pro and geoJSON? In this tutorial I will cover this basic task.
We all played around with this little thing: wood labyrinths with one or many little balls called a “Ball-in-a-maze puzzle”. The goal was to find a path through the labyrinth so the ball was not trapped by the holes in the board: Google leveraged the idea itself and made a funny little game PlayMapsCube out of it to communicate the ideas and logic behind one of its main products: Google Maps.
Two years ago I wrote the OSMroute plugin which enable the QGIS user to use the OpenRouteService API for geocoding of points, accessibility analysis as well as routing from A to B. Unfortunately the managing of a plugin/ open source tool is time-consuming/ hard. But fortunately Nils Rode lifted the plugin to a new level: OSM tools.
Some days ago a new version of the ALOS 30m DEM was released: Void pixels due to clouds and snow pixels within 60 deg. of north and south latitudes in Version 1 were complemented by existing DEMs. Out of the areas are same with Version 1 product. As we already compared ALOS with SRTM-1(I saw the ALOS DEM as “the winner”) I am now interested in how this performs in a another setting. We are changing our focus from Mongolia to Germany and check how the new ALOS DEM works compared with SRTM 1.
QGIS 3.0 is the next big release in terms of features and tools. As it is stated in this e-mail chain we could expect this new major release in late 2017 and time is passing fast: retire 2.14 in June 2017 2.18 becomes LTR from June 2017 to 2018 3.0 feature freeze in July 2017 release 3.0 in Sept 2017 release 3.2 as next LTR in release 3.0 + 4 Months (eta June 2018) Yet this timeline is not strict and [was?] under discussion. We might expect a new candidate loaded with some cool and uncool features.
As I realized that I have a really huge family I was keen to digitize the current family tree and get into contact to my relatives. For getting things done, I choose the open source genealogy software Gramps to record all offline information about my family members and create a database as base for further investigations, updates and of course spatial visualization. After that, I exported a database view and visualized it with QGIS.
For a geomorphological study that I am working on I want to produce topographic swath profiles across a mountain range, that is, I want the average elevation along a profile plus the min and max values within a certain distance of said profile. I have used three different methods to achieve that and found some nice resources that I’d like to share with you: GMT – Generic Mapping Tools GMT is a powerful suite of command-line small programs to manipulate all kinds of geographic data (Wessel and Smith, 1998; Wessel et al., 2013). A walk through on how to produce…