Author: Zander Venter

Climate analysis

Zander Venter

Global cloudiness. I have always wondered where on earth am I the most likely to get depressed from lack of sunshine.

I made this image of the average number of cloudy days per year picked up by the Advanced Very High Resolution Radiometer (AVHRR). Dark blue areas have nearly 365 cloudy days, while light tan areas have hardly any.

It is amazing how you can pick up continental boundaries and even major rivers purely from cloud frequency alone. Looks like Gabon and Singapore are some of the gloomiest places to live.

For other examples check out this Instagram page.

Agricultural change

Zander Venter

Bloemhof dam and surrounding agricultural fields along the Vaal river in South Africa. Can you make out the funky seahorse blowing bubbles?

This image was obtained from the vertical co-polarization from the synthetic aperture radar sensor on Sentinel-1. Scenes in January, June and December of 2016 where assigned to the red, blue and green bands, respectively. We cahn use such images visualize change in colout. Landcover that has changed over the year displays with more vivid colours.

For other examples check out this Instagram page.

Water quality

Zander Venter

Fiery oceans. The red flame-like shapes burning in this image are actually indications of very high water (ocean and lake) chlorophyll concentrations. Chlorophyll is a pigment found in plants and algae. You can see the effect of the easterly trade winds which cause massive upwelling of nutrient-rich water off the West coast of Africa. This causes algal blooms which can be detected with the MODIS satellite. This image encompasses all the MODIS imagery for 2017 combined into a median mosaic.

For other examples check out this Instagram page.

Rangeland managment from space

Zander Venter

Rangelands cover 50% of the earth’s surface. The average livestock farmer has to manage hundreds to thousands of hectares of this precious resource on foot, horseback or vehicle – a colossal task.

For the first time, freely available satellite imagery can give farmers a bird’s-eye view of their farm from space. The only problem is that accessing this imagery is very difficult and once you have it, interpreting it is even more challenging.

SpaceGrazer aims to solve this problem. Farmers who use the SpaceGrazer mobile and web app, are able to obtain real-time satellite imagery and statistics on their farm’s forage availability, quality and a host of other user-friendly data.

All the farmer has to do is register, digitize their grazing camps/paddocks, and we will do the rest for you. Some of the information provided includes:

  • Forage quality and availability scores down to the camp-level
  • Interactive 3D maps of forage biomass
  • Rangeland degradation status
  • Woody plant cover maps
  • Interactive historical trend graphs of the above stats
  • Forage forecasts and early warning systems
  • Grazing rotation management tool

According to the Food and Agricultural Organisation, meat and dairy consumption is set to increase 75% by 2050. For farmers to meet this rise in demand without compromising rangeland condition, they need tools such as SpaceGrazer to increase efficiency and sustainability.

Check out the SpaceGrazer app here: SpaceGrazer

Woody plant encroachment inspector

Zander Venter

The march of the woody plants! Although deforestation has been quantified and talked about in the media a lot, there is another trend taking place on the quiet outside of forests. Woody shrubs and trees have been increasing over Africa according to a new study conducted by ZSV consultant Zander Venter. Woody plant encroachment can have serious negative consequences for rural and commercial rangeland managers. Trees take up space that grasses would occupy and grasses are the most important forage resource for livestock. Trees can also drink large amounts of water from the ground and affect local hydrological cycles. This woody plant encroachment inspector web app gives striking examples of woody plant encroachment in South Africa using fixed-point photographs from the rePhotoSA database.

 

Play around with the app here: Woody plant encroachment inspector

Fire inspector app

Zander Venter

Fire can be a villain and a hero. It poses a significant threat to human lives when it comes too close to our dwellings. Yet, it is also a key part of most ecosystems, allowing vegetation to turn over a new leaf. Until recently the extent of this global phenomenon has been difficult to quantify. Using the MODIS satellite, which flies overhead twice a day, we can identify fires from space. The imagery has been difficult for scientists let-alone citizens to access. With this new Fire Inspector web app, anyone can investigate where and when fires have occurred over the globe during the past two decades.

 

Play around with the app here: Fire Inspector

Africa burns

Zander Venter

Fire can be a villain and a hero. It poses significant threat to human lives when it comes too close to our dwellings. Yet, it is also a key part of most ecosystems, allowing vegetation to turn over a new leaf. This animation shows fires over Africa for the past two decades. Pixels that are burned repeatedly get hotter colours through time.

Human footprint

Zander Venter

We live on a constantly changing planet but are often unaware of how much we as humans contribute to that change. Over the past few decades satellite technology has advanced and has given us insight into our collective footprint on the planet. It is immense. This timelapse shows the impact of Cape Town citizens on Theewaterskloof dam levels exacerbated by drought.

Check out other aspects of our footprint in this video:

Hungry cattle from space

Zander Venter

Integrating animal GPS movement data with satellite imagery is a great way to visualise an animal’s interaction with its environment. This animation shows GPS points from three collared cattle moving over a farm grazing camp. The animals are herded in thin grazing strips each day using electric fencing. With an NDVI (normalised difference vegetation index) overlay from Landsat and Sentinel satellite imagery you can see the impact they have on the vegetation. Like lawn mowers they sequentially demolish the small strips of grass one day at a time.