Author Archives: pvanb

About pvanb

I am a tropical forest ecologist with a focus on spatial and temporal patterns and processes at population and ecosystem level. I am furthermore very interested in issues related to conservation and sustainable use of biodiversity and natural resources under current and future climates. I have worked in the Middle East (Syria and Lebanon) and South America (Brazil) and in Eastern Africa (Kenya).

Computing MESS in R and GRASS – a speed comparison

The Multivariate Environmental Similarity Surfaces (MESS) is an index that represents how similar a point is to a reference set of points, with respect to a set of predictor variables (Elith et al (2010). The function was first implemented as part of the Maxent software package, but is now also available in R and GRASS. Below, I will compare how fast the different implementations are. Continue reading

Access GRASS 7 data in QGIS

QGIS supports GRASS in two different ways. 1) For those working with GRASS databases, there is the GRASS toolbox, which basically offered an alternative GUI to GRASS. For those working with other data types, most GRASS functions are now available through the processing toolbox.

I do most of my spatial analysis in GRASS, while I use QGIS amongst others to create maps based on the results. So I mostly used the GRASS toolbox. Unfortunately, the GRASS toolbox doesn’t work (yet) in QGIS 2.6. So what now? Well, as it turns out, QGIS can access GRASS raster layers through the QGIS browser. Continue reading

Locus Map Pro carries its support for MBTiles to the next level

I wrote before about the MBtiles format, a convenient format to store tiled maps in a single portable sqlite database. Probably the easiest way to create them is with Tilemill, as described here. The format is supported by amongst others QGIS, but it is especially suitable for use with map viewers on your mobile device.

The format is now supported by various mobile map viewers, including e.g., Geopaparazzi and OruxMaps. One I like for its rich set of features is Locus Map Pro. I normally only write about open source, but I think the developer of this app deserves some credit for being one of the first (as far as I am aware of) to support the MBtiles format.  Up to very recently you could only view maps in MBtiles format (similar to the other viewers mentioned above), but with the latest update support for the UTFgrid feature has been added.This basically adds interactivity to your map.
Continue reading

The all new and shiny QGIS 2.6 is out

QGIS Brighton (2.6) is out, with tons of new features and improvements. Check it out on http://qgis.org/.

For an overview of the new features, check out this change log. You really should check it out. I just had a look and although I am using the trunk and beta versions for some time now, I still noticed quite a few new features I hadn’t discovered yet!

Update of Zim-wiki export template for an adaptive website

A short note that I updated my export template for a adaptive website to work with Zim 0.61. You can find it on my github page. It is very much work in progress, but perhaps it will be useful to somebody.

Examples of websites that were created using this template are http://notebook.ecodiv.org,http://maps.vegetationmap4africa.org/docs.html and http://www.penwatch.net/morrowind_dnd_zim/.

UK to adopt ODF as standard format

This could be an important move, the UK adopts ODF as standard format for government documents. Stated reasons; the open standards will reduce the cost incurred by users and it will be easier for them to work with the government when they use ODF.

Perhaps this may also compel Google to support ODF in Google Docs (ironically, the latest MS Office products seems to support ODF better than Google Docs, but anyway..).