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GIS shapefile format

Shapefiles that can be imported into GIS software can be downloaded from the UKCP09 User Interface . They are available for any gridded variable for which a map is available (with the exception of maps of aggregated areas, i.e. administrative regions and river basin areas).

Careful consideration and caution is required when working with the shapefiles, in order to ensure that the results of any of your work in a GIS are scientifically valid.

Where can I find them?

GIS shapefiles can be accessed through the output page of the User Interface . Simply select the 'shapefile' option from the drop-down selection when saving your request.

Shapefiles are only available if you select one emission scenario, one variable and one temporal selection. They are also only available for the whole of the UK. You will therefore need to select 'Entire UK' for location, and then 'Map' as output type.

How can I use them?

Shapefiles can be used in several ways:

1. To import UKCP09 data into a GIS programme

Shapefiles are saved as a zipped file due to their size. You will need to extract the zipped file first before you load the file into GIS software such as ArcGIS. Once you have opened ArcGIS, click on the 'Add' symbol to add the data. Browse to where you have saved the file and select the file with the file type .shp. This should produce a rotated grid of all the shapefiles.

You may wish to obtain a digital background map so you can see the outline of the British Isles. These are available for download from the Ordnance Survey website

2. To examine the range of uncertainty both within and between emission scenarios

GIS is a useful tool for establishing and visualising the range of uncertainty within and across emission scenarios.

For a given emissions scenario you can map the range of uncertainty for a given variable. For instance, you could visualise the range between the 10 and 90% probability levels for summer mean temperature for a given emissions scenario.

If you want to visualise the full range of uncertainty for a given climate variable across all emissions scenarios, it is possible to do this using GIS. To do this you must subtract the value of the climate variable at the 10% probability level for the Low emissions scenario from the value of the 90% probability level for the High emissions scenario. This would result in a map of the total range of uncertainty.

The above two cases represent the only situations where it is valid to use the UKCP09 data to establish ranges.

Things to be aware of

There are several things you need to bear in mind when using shapefiles:

1. They are not available for sea level rise.

Shapefiles are only available for climate projections over land in the UK so you will not be able to obtain shapefiles for sea level rise.

2. Shapefiles for more than one variable should not be overlaid.

The nature of the data means that it is not scientifically valid to use two different UKCP09 variables in an analysis.

The shapefiles were created using the CDF data. Each shapefile contains data for one probability level. For guidance on how to use CDF data please see the 'CDF data' pages.

3. They should not be considered to be weather map data when used within a GIS

UKCP09 shapefile data does not presenting a snapshot of a distribution of the climate at a particular time with all the grids square values spatially coherent. A UKCP09 map does not provide the same information as that provided by a weather map or a map of observed climate data and should not be analysed and interpreted as such.

Maps created using the shapefile data should be interpreted like other UKCP09 maps.

For guidance on using UKCP09 maps please refer to the sections on 'Customisable Maps' and to Section 4.3.1 of the Climate Change Projections report.

Need more help?

For questions and queries about UKCP09 please see our Help section.