relating land cover raster to vector data

Question

I have a land cover raster basemap that covers different land cover/uses in Europe to 100m resolution and a separate Excel legend file. Separately I have a point shapefile with the details and location of archaeological sites, most of the sites fall into the landuse category of agricultural land, but I want to show this more clearly with a simplified map, and to eventually display a table showing something like "Pastoral Land 3 sites
Arable land 10 sites" etc

I vectorised the raster at first, but am not sure if that was the right thing to do. I am playing around with habitat evaluation plugins, but what I really want to find out is a technique of evaluating the relationship between the vector point (site) and the basemap (landuse), rather then going through the rather arduous process of manually zooming in and noting the position of the point and the colour of the pixel, then going through the legend. To make the final result clearer on a printout display Id also like to change the image resolution.

Is there a specific plugin I can use for this work? I also am trying to reclassify the raster as the detail now is more than I need.

I am using QGIS 2.8 Vienna. Below is an image of the two layers

Answer 1

You can extract raster values of land cover classes to the point shapefile of archaeological sites using Plugin: Point sampling tool which can be downloaded from plugin manager in QGIS.

The tool works perfectly if the projection of the raster(s) data and the point shapefile are same. Working with different projections for the raster(s) and shapefile data will create a shapefile with empty columns of raster values.

After assigning the land cover classes to the points of archaeological sites, you can change the style of those points based on the land cover field. In other words, you can classify the points of archaeological sites based on the land cover categories, as you can see below

The numbers from 1 to 999 are the land cover categories, and the number within the square brackets beside each land cover class represents the number of points within each land cover class (counts the number of points within each land cover class).

There are two ways to count the number of points (archaeological sites) within each land cover class:

1. Use the legend in QGIS. When you add the archaeological sites in the legend in QGIS make sure that Auto Update is unchecked. Then use "Show feature count of each class in vector layer" as you can see below.

2. The second way is to represent the data as table instead of legend. To do so, you can use Excel to open the DBF file of the output point shapefile (archaeological sites) after assigning the land cover to it, then count the number points located in each land cover, and save that file as CSV file. Do not overwrite the original DBF file of the point shapefile that you opened, it may corrupt the file. Just save the file as CSV. If you want to add the CSV table into the QGIS layout you can refer to this answer of the question: Adding excel table to QGIS print composer? for more detailed explanation.