The software of GIS (Geographic Information System) allows the user to manipulate and manage spacial data. For this project, we used GIS to create a map of the study area and to make different layers for different information.
This image shows the Loonse en Drunense Duinen National Park. The area within the red lines is the total area covered by the drone that will be used in the report.
The individual images taken by the drone are stitched together to form the larger map. Using that map as a base, new layers can be added to the map to describe different properties about the area. Four different maps were created: ground cover classification, NDVI (Normalised Difference Vegetation Index), vegetation height, and a succession map. These maps will be described below.
The maps to the right show the different ground cover by using the drone images. The map shows trees surrounding the heath and sand dunes.
This was done by taking small groups of pixels within different sections and applying a category to it. This is done to “teach” the software to recognise the different coverage types. Once this is finished, the software will apply this to the entire map.
A NDVI layer was created for the dune area. This NDVI uses the principle that live vegetation absorbs certain wavelengths of radiation. Plants use photosynthetically active radiation as a source of energy, thus, chlorophyll in plants absorbs visible light.
Near-infrared light is reflected. This knowledge was used to make a layer indicating which vegetation is active. This results in different values for different vegetation types.
This method was used as a more reliable way to distinguish between the vegetation types.
On this map, vegetation can easily be distinguished from bare soil, in this case sand. In this map, most trees have a high NDVI value, shown in green. Heath and grasses, however, are seen in a more yellow and/or orange shade.
This map gives an idea of the trees found on this location at the date of the height measurements. As these measurements likely occurred in 2010, the map shows some trees have since been cut down in the Life project. The LIFE project aims to create and restore Natura 2000 habitats. More information can be found in the About the Project section.
In this case, the project took place between 2009 and 2013 and was financed by the province of Noord-Brabant.
Together with the drone photographs, this map can still give an indication of the location of trees at this point in time, as most trees along the edges are still present. The tree height also gives an idea of the age, and possibly the type of tree found.
Using the vegetation height map, a new map was made showing the land cover types when including the vegetation height for classification of trees. This image shows the difference between using and not using the tree height in classifying the land cover types.
A succession map was created by using outside sources from previous years. This map makes clear that since the Life project in 2011, the drift-sand area has been quite steady over the years. The largest increase in sand area seems to have taken place in the north-western part of the park, where trees and the topsoil layer were removed.