Hello,
I am doing some research on how agricultural land use is affecting the functional diversity of birds. In order to do this, I need to work out the % agriculture, natural forest and habitat diversity of each 10km site across the whole UK.
I have a shapefile of all the 10km sites and have downloaded the UK land cover map for 2015 and crop maps.
Does anyone know how I can work out these percentages for each site? Either using R or I have downlaoded QGIS but not used it before.
Many thanks,
Rebecca
QGIS can easily be used for this. Once the area of study is clipped, all you have to do is open the attribute table of the corresponding shapefile and calculate the area using the field calculator tool (link 1). If the coordinate system (CRS) of the shapefile you're using is set as latitude and longitude (degree units), you'll have to project this file first (transform to UTM - metric units). This process (link 2) is needed because the output area unit varies according to the CRS of the shapefile. If the CRS is set as UTM, the output area unit will be in square meters (m²).
Link 1: https://www.youtube.com/watch?v=TKSu9Dg1wHQ
Link 2: https://www.youtube.com/watch?v=DZX5xhNVEyk
Hope that helps!
Hi Rebecca
As you already have the land cover map, all you need to do is add the geometric columns/forms to your site shapefile to get the area occupied by each site or class by going to vector, then geometry tool and finally export/add/geometric columns.
Specify the input shapefile well in case you have several active layers.
To have real values (in m²), you will have to reproject the shapefile of the sites in UTM.
To finally get the % of each site, the "group stat" extension that you will have to install beforehand, will allow you to have the final result.
Useful link: https://www.youtube.com/watch?v=4fFAun9Z1m0
Translated with www.DeepL.com/Translator
Daddy
Dear Jenkins
The previous answers are quite complete.
But let's go:
1) cut mask (10km shapefile) x land use 2015;
The result of this operation is land use 10x10km for 2015;
2) If not in metric coordinates, transform the result from step 1 to the desired system;
3) Open the attribute table of the previous layer;
4) Turn on the edit and open the field calculator (see previous videos);
5) Set up the operation on the calculator and generate a new column with the areas then create another column with the% percentages of each land use.
Which SRC system do you intend to use?
Best Regards
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