08 August / / Interest
We’ve all been watching with horror as Covid-19 runs rampant worldwide. In South Africa, there has been particular concern about the rapid spread in the Western Cape, where more than half the current confirmed cases have been reported. Pundits wax lyrical with pet theories, but a favourite (at least among those outside the province) is that people from the Cape are slackers and haven’t been taking the lockdown and social distancing rules very seriously.
I have found that one of the biggest challenges as a scientist working on global change issues in South Africa has been not having access to my country’s long-term weather records. Our weather service charges for the distribution of data (despite it being collected with taxpayer’s money), and a hefty fee at that. While one can occassionally access data for research purposes, this is usually only if there’s a student involved, and requires tracking down an individual within the organization who’s willing to field your query.
21 November / / Interest / Research
This is an updated quick and dirty analysis of the CapeNature fire database (spanning 1927 to 2018) to see if the major drought that is currently being experienced in the Cape Floristic Region has had any impact on the occurrence or extent of wildfires. I first ran this analysis in 2017 and have been updating it every year. Wildfires are an essential component of fynbos, but components of the fire regime such as return interval need to be within certain bounds of variability to maintain healthy ecosystems.
11 March /
The City of Cape Town’s Draft Water Strategy is out for comment until the 15th March. This post provides a quick and opinionated précis of what it contains and the comments I’ve sent to the City. Even if you don’t agree with me, I encourage you to write to the City and have your say. The Strategy in brief The document is structured around 5 “Commitments”, which are defined as “A willingness to give our time and energy to something that we believe in, a promise, a firm decision to do something”
The Basics Interlude Doing GIS from R Since I first started maintaining blog posts on handling spatial data in R perhaps the most common question I’ve received is “How do I handle big spatial data in R?”. I thought its finally time to provide a blog post to deal with this particular topic. The answer of course is that there are many, many ways. Now I know those of you who have asked me in person are thinking “That’s not what he said when I asked?
A quick note on the structure of this tutorial Data Description Housekeeping Getting and cleaning the data, but first and foremost, projection!!! Let’s start with point data Raster data (mostly functions from library(raster)) Polygons! Going parallel!!! Animation! Some other data visualization and analysis But what about our poor cedars? Options for writing out spatial data This post follows on from Handling Spatial Data in R - #1.
Installing R (and RStudio) CRAN Spatial Task Views!!! Useful DIY resources Points, lines, polygons and rasters - R can handle them all. My aim for this post is to give you the basics required to teach yourself spatial data analysis in R - following 3 major sections listed above. In the next post I provide a practical example working with point, line, polygon and raster data. If you’re already familiar with R then you can skip straight there, but you may be interested to check out the useful DIY resources before you go.
The current drought experienced by Cape Town and surrounds has brought the issue of climate change to the fore in public discourse (if it wasn’t already). It’s discussed extensively in the media and plays a prominent role in the City’s Water Outlook 2018 Report (Version 25 - updated 20 May 2018) as motivation for the need for long term bulk water augmentation schemes.
28 February / / Interest
This post provides an interactive visualization of the results of Le Maitre et al. 2016. Estimates of the impacts of invasive alien plants on water flows in South Africa. Water SA Vol. 42 No. 4. It aims to highlight how much water could be reclaimed by clearing alien species from our catchments. The extreme drought that is gripping Cape Town and surrounds has municipalities desperately seeking options to augment bulk water supply.