Land Cover Mapping


Overview maps
General overview maps can be created from very high resolution data sets to cover a specific area. General cartographic information can be portrayed and feature extraction can be performed to transform features in a high resolution satellite images to vectors. This can be especially relevant for extracting features such as roads, buildings and other structures in order to perform GIS analyses or to update or perform quality checks on existing map data.

Land Cover / Land Use Mapping
A satellite image often contains information that can readily be analysed visually. In most cases it is possible to get an idea about the relative importance of urban areas, forests, agriculture etc. just by looking at the image.

Nevertheless, it is in some cases necessary to convert the satellite image to a thematic map of different land cover or land use types. This will make it possible to work quantitatively with the characteristics of the area and to analyse and understand the distribution of different land cover types.

When converting a satellite image to a thematic map of land cover classes it is possible to perform simple calculations like the overall area of each class. However, more detailed analyses can generate a deeper understanding of the area, i.e. by looking at the degree of fragmentation of the area or the distance from a specific class to a specific feature. With this information it is then possible to analyse how far deforested patches in a tropical forest area are located from roads or settlements, or to analyse which agricultural crops are grown on the steepest slopes.

Change detection
Using time series of satellite images, it is possible to calculate the degree of change between predefined land cover classes. In this way, changes in the areal extent can be calculated over time. For instance, a typical task would be to determine how significant the deforestation rate has been in tropical forest region and to examine what land cover class the forest has changed to. These analyses can be combined with GIS modelling to predict future scenarios.

Applications
Typical applications of land cover mapping are for instance: 1) generating input for hydrological models 2) analysing environmental degradation or ecological stability or 3) updating agricultural statistics such as crop types, fallow periods etc.