So what does 'GIS' actually mean for us?

You are not alone in asking that question! When I trained in Geography 20 years ago, it was the new thing. I then put it to one side and hardly thought about it, until now.......

GIS stands for Geographical Information System.

It's a way of storing, organising and presenting information, and combines mapping, databases and statistics.

You probably have some experience of this already, if you have ever used satnav, or GoogleEarth, or a handheld GPS, or if you've tried to get rid of that irritating map on facebook.

 Basically, you start with a base map. This is usually a really good satellite image. The newer satellite images can have a pixel size of 0.5m x0.5m!

You load this into your computer program, and then you can start adding more data, a 'layer' at a time.

So for example, if I went to Hawks Nest Pond today (what a great idea), I could take my GPS and walk the boundary of the new reserve. I could then save this data in the program and produce a new map. This would be a really small data set! If you counted all the albatross in the islands, or entered all the climate data for the last 50 years, you would be using much bigger data sets.

Once you have some data and some base images, you can start to ask your GIS to do all kinds of amazing things.

 

If I had the digital version of the geological map, and my Hawks Nest Pond boundary, I could find out what kind of rocks and soils were there. If I had done the right work on the plant records for the islands, I could predict what kinds of plants would be most likely to grow there; by combining the data set for 'places where we have found silvery buttercups' with the geological map, we could start to make predictions about other places where they might be found growing.

GIS also allows us to map and interpret changes over time. This is likely to be particularly useful if we really are experiencing a changing climate. We can look at all kinds of relationships between rainfall, changing vegetation cover and land use, to help landowners and managers to make decisions about how to get the best from their land in the long term.

Why now?

GIS has clear benefits for conservation planning; if you have data about the important species and habitats you want to conserve, and other data about the land available for conservation, either because it's already a nature reserve, or because it's publicly owned, or because its owners already manage it for conservation, then you can start to assess how you are doing and what you need to do next. There are various tools around to help with this. One is a computer program called MARXAN; you put all that data into it, and it tells you where you should be focussing your efforts.

One of the objectives of the Protected Areas Project is to have a good look at MARXAN to see if it would work for us. Over the next few weeks I'll be putting out some feelers to try to find out what data is available to use for this- this kind of thing is only as useful as the data you put into it. Unfortunately, there are a few stumbling blocks right at the start:

• satellite imagery; you know how I said at the start that you need a high resolution satellite image.....well, we don't have any. They are expensive. Who will pay?
• data; masses of high quality data has been collected over the years but it is all in different places. I haven't tried too hard to look for it yet, so wish me luck with that!
• a base map; there seems to be a digital map produced by the military, but we don't seem to be able to use it. Otherwise we are reduced to a scanned version of the 1963 OS map. Or GoogleEarth; have a look at the image for Sea Lion Island for a demonstration of the limitations of this!

We are not downcast by this; the South Atlantic Environmental Research Institute has this right at the top of its agenda; an island wide GIS is what we need, and this time around, we might actually be going to get it. It opens up a whole new can of worms, to do with data and copyright issues, and whether we all give up our data to allow other people to use it.

(The images are from a presentation given by Justin Moat, head of GIS at Kew. I wish I could explain it as well as he did.)