Posts

This blog serves as a combination of blog and personal notebook. I’ll might write about the use of open source software in research and education, or more specifically, about the use of GIS and other analytical tools. However, once in a while, I might get inspired and write about a totally different subject. We’ll see.

Switching to Quarto

I just finished porting my blog, based on blogdown and Hugo, to Quarto. Main reason was a number of small but handy improvements. Main challenge was to find all those small tweaks and make them work in the new setup. But it all worked out nicely.
Oct 25, 2022
2 min

Removing the background in a picture

With a single line of code

With only one line of code, the rembg package finds the object of interest in a picture and removes the background. Or, at least, that is what it promises. But does it hold up to that promise? tags: U2-Net, image segmentation, image classification, deep learning, artifcial neural network
Oct 8, 2022
3 min

Working with the global Building Footprints data

Or, how to deal with very large geojson files

The open building footprints from Bing Maps is a great data set. However, it is not an easy one to work with due to the size. Luckily, with just a few lines of code, you can split the file in manageable chunks that are easier to deal with. tags: GDAL, OGR, open data, Nepal, data import, data wrangling
Jun 5, 2022
6 min
tutorial

MODIS fire data in GRASS GIS

In this post I show how to import 8-day MODIS satellite images from 2002-2021 in a GRASS GIS temporal database, and how to compute some summary statistics based on these data layers. tags: MODIS, Fire frequencies, Satellite image
Mar 27, 2022
15 min
tutorial

Calc - Importing tables from web pages

To grab a table from a website isnt terribly difficult. One can simply copy and paste it in your document. But especially if the page contains many tables, there is an easier way to get the tables in your LibreOffice spreadsheet. tags: webscraping, Calc, Spreadsheet, tables
Feb 20, 2022
1 min
tutorial

Create a QR code in Libreoffice

If you are using a software tool for a long time, it is easy to miss out on (new) features. Like this cool feature in Libreoffice to create a QR or barcode. And it is really simple. Tags: QR code
Feb 20, 2022
0 min

Upload raster labels to a point layer attribute table

Introducing the v.what.rast.label addon. An little utility to sample the raster values and labels at point locations defined by a vector point layer. Values and labels are written to the attribute table of the point layer. tags: grass gis addon, data wrangling
Jan 23, 2022
5 min
tutorial

Latest GRASS GIS addons now also available for Windows

For Window users, several new GRASS GIS addons that were published recently did not show up in the list of available addons when running the g.extension function. But as a great start of the new year, this has now been fixed.
Jan 1, 2022
0 min

Storing styles and metadata in a GeoPackage

Or why it is so easy to share you data using a Geopackage.

There are many reasons to like the GeoPackage. One is that it makes it so easy to share your data, including symbology and other layer properties in one database file. And what makes this even better is that you can also store QGIS projects directly inside GeoPackage files. tags: Geopackage, layer properties, data storage, open data
Dec 31, 2021
2 min
tutorial

Playing with animal tracking data in QGIS

Using the Temporal Controller in QGIS to visualize the movements of cattle in the Logone Floodplain in Cameroon. Based on data from the Movebank, a free, online database of animal tracking data. tags: movement data, data visualisation
Aug 30, 2021
11 min
tutorial

Compute the area per category

Exploring different methods to do this in GRASS GIS

A short note about different ways in GRASS GIS to create a raster layer with as values the surface area of the categories in another raster layer. tags: GIS, data exploration
Aug 3, 2021
7 min
tutorial

Distance between features

Calculating the distance between features (points, polygons, lines) is a common GIS task. In this tutorial I will calculate the nearest sighting of mountain lions to Minnesota in GRASS GIS. tags: GIS, spatial analysis, GeoPython
Apr 3, 2021
6 min
tutorial

Import GBIF data

The Global Biodiversity Information Facility (GBIF) is an international open data infrastructure that allows anyone, anywhere to access data about all types of life on Earth, shared across national boundaries via the Internet. tags: biogeography, data import, species distribution, occurrence data
Jan 11, 2021
0 min
tutorial

Interactive dashboards with R

Build on Flexdashboard, Crossover and htmlwidgets

Dashboards provide a great way to communicate information and insights about a particular set of data. In this post, I provide an example of a static, but interactive dashboard build in R. tags: dashboard, R, flexdashboard
Dec 21, 2020
5 min

Linking spatial and non-spatial dataframes

Note, the order in which you link does matter

When linking a spatial dataframe and a non-spatial dataframe in R using the the dplyr syntax, note that the order in which you do this matters. tags: sf, dplyr, SQL
Dec 6, 2020
2 min
Tutorial

Access soilgrid data using the WCS protocol

The soil data layers from soilgrid.org provides access to grid layers representing the spatial distribution of soil properties across the globe. This post provides an example of how to use the OWSLib pacakge to access these soil grid layers for your area of interest. tags: soilgrid, OWSlib, open data, data import
Nov 25, 2020
7 min
tutorial

RStudio meets Zotero

RStudio with a visual RMarkdown editor mode and Zotero integration

There is certainly something to look forward to in the upcoming RStudio version 1.4. With the all new visual RMarkdown editor and integration with Zotero, you can not only run your analyses in RStudio, you can also write the report with ease. tags: reference manager, bibliopgraphy, RMarkdown, open source, open data
Sep 28, 2020
0 min

Tree species diversity distribution

Estimating tree diversity distribution patterns using the r.series.diversity addon for GRASS GIS

A short description how to use the r.series.diversity addon for GRASS GIS to generate maps of the tree species diversity across the contiguous USA, based on tree species distribution data by Wilson et al. 2013. tags: biodiversity, biogeography
Jul 29, 2020
8 min
tutorial

Huis ter Heide

You may get depressed from all the news about the loss of our biodiversity in the Netherlands. But that doesn’t mean there aren’t still beautiful places to be found. A few days back I happen to stumble upon one of these hidden gems, Huis ter Heide, an estate owned and managed by Natuurmonumenten (Dutch Society for Nature Conservation).
Jul 25, 2020
2 min

Adding functions to the QGIS toolbox

The graphical modeler is a great way to automate tasks, using the routines in the QGIS processing toolbox. However, what to do if you need a function not available in the toolbox? In that case you may want to look into writing your own script. tags: QGIS processing toolbox, automation
Jul 23, 2020
5 min
tutorial

GISQuick

An easy way to publish your map online

There are several ways you can publish or share your maps, created in QGIS, online. One very easy way is to use the Gisquick publishing platform. It basically requires two steps only; create a QGIS project, and upload it. tags: online map, data sharing, open source
Jul 15, 2020
4 min
tutorial

Import NASA DEM in GRASS GIS

Easy and quick using the r.in.nasadem addon

Importing the NASADEM_HGT dataset in GRASS GIS is greatly facilitated with the r.in.nasadem addon. tags: SRTM, DEM, altitude
Jun 26, 2020
4 min
tutorial

QGIS 3.14 is there

There is always this buzz that comes with new releases of QGIS. I guess this is because the development goes so quick, and each and every release brings something new and exciting. tags: software release
Jun 23, 2020
1 min

Legend for continuous raster in QGIS composer

This blogpost shows in a few steps how to add a continuous colour legend for a raster layer in a map layout in QGIS. It is a work around, but it works. tags: legend, visualisation, legend
Jun 21, 2020
2 min
tutorial

Creating a map with inset using tmap

Plotting maps with tmap and adding nicely aligned legend and inset map. tags: R, cartography
Jun 20, 2020
6 min
tutorial

Recording sounds

Recording bird sounds Using Audacity About the audio player Recording bird sounds I like bird watching, and I would like to improve my skills in recognizing bird sounds. To that end, I recently bought a small audio recorder (the H1n handy recorder, for those interested). tags: bird songs, nature, sound recording, Audacity
Jun 14, 2020
1 min

De Grote Geo Show

The Grote Geoshow is a Dutch show on Twitch (live) and YouTube by the OSGeo.nl foundation and friends. It airs every Thursday afternoon and is all about open geo topics. tags: open source, qgis
Jun 13, 2020
0 min

New GRASS GIS website

GRASS GIS is a fantastic software package, not only one of the oldest GIS packages still around, but also one that is continuously updating and improving thanks to a vibrant community.
Jun 13, 2020
0 min

Comparing human population density maps

Population density maps have multiple implications, e.g., to help relief agencies to better plan where they are needed most in case of disaster and in demographic, economic and environmental research. tags: demography, data quality, population density
Jun 12, 2020
2 min

Migrating from ecostudies to ecodiv

Ecostudies EOL A new solution Using blogdown Migrating old posts Ecostudies EOL I have kept a blog on Ecostudies for quite some years. It was mostly about using open source GIS tools. tags: Hugo, web publishing
Jun 12, 2020
1 min
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