tag:blogger.com,1999:blog-3551353128022429074.post7027850930607951061..comments2022-03-28T02:03:50.210+01:00Comments on Skrifennow: Speakers of the Welsh language according to 2011 census.MawKernewekhttp://www.blogger.com/profile/03079953492549786059noreply@blogger.comBlogger3125tag:blogger.com,1999:blog-3551353128022429074.post-45966835642175666812015-01-21T23:56:07.015+00:002015-01-21T23:56:07.015+00:00The other thing I haven't explicitly mentioned...The other thing I haven't explicitly mentioned is that it is necessary to join the data to the polygon shapefiles, which is done in the standard way of using "Layer Properties" and Joins on the side tab in the window that comes up. MawKernewekhttps://www.blogger.com/profile/03079953492549786059noreply@blogger.comtag:blogger.com,1999:blog-3551353128022429074.post-44305872755718265562015-01-21T23:30:52.924+00:002015-01-21T23:30:52.924+00:00It doesn't involve any actual programming as s...It doesn't involve any actual programming as such. <br /><br />There are three main steps. <br /><br />First clip the census output polygons (which are themselves downloadable in shapefile format from the ONS) to whichever areas you want to assume are areas of settlement. This I did with the built-in Clip plugin under Vector-->Geoprocessing tools. The first time I did this I used a vectorised elevation map to select areas under 300m. Although Wales has a good deal of land over 300m the only census polygon that vanishes entirely under this scheme is in Blaenavon. <br /><br />Once I got hold of the OS Opendata buildings layer, I could clip the census polygons to buildings. Of course these can be any buildings not just residential so might overpopulate areas with lots of large warehouses and underpopulate areas with compact high-rise flats. <br /><br />The second step was to create the dot distribution, which is another plugin called Random Points which appears under Vector-->Research Tools. This chooses randomly a number of points given by a column in the attribute table of the vector within each extent polygon.<br /><br />The third step was a heatmap under Raster-->Heatmap which allows you to choose a scale on which to map the density of points.MawKernewekhttps://www.blogger.com/profile/03079953492549786059noreply@blogger.comtag:blogger.com,1999:blog-3551353128022429074.post-54732639435834895852015-01-21T22:59:03.927+00:002015-01-21T22:59:03.927+00:00Neat. I'd like to learn how you restrict the m...Neat. I'd like to learn how you restrict the mapping to buildings polygons. Which QGIS plugin did you use? Have you code you could share? Hywelhttps://www.blogger.com/profile/03784606152848601156noreply@blogger.com