ERS-SAR Applications

A first and very important step that each remote sensing related project should take is to evaluate the adequacy of a satellite sensor for a given application.

Thus, a number of applications were investigated in order to identify those which might profit greatly from the use of information obtained through the interpretation of ERS-SAR data. The following criteria were applied:

• the economic value of the application (e.g. the detection of mineral resources),
• the environmental value (e.g. information on the degradation of forests),
• the political value (e.g. information on the availability of food resources),
• the technical feasibility,
• the existence of reliable processing methods to be applied by the institutions of the countries concerned.

In general, the following applications can be considered when talking about the use of high resolution satellite data:

• monitoring of forest,
• monitoring of agriculture,
• monitoring of urban areas,
• geological mapping,
• cartography,
• monitoring of coastal zones,
• monitoring of the maritime environment.

Whereas mapping is defined as the evaluation of a relatively stable situation (map up-date every 10 years), monitoring is defined as the evaluation of a dynamic process (deforestation detection on an annual basis).

The requirements for the different applications can vary depending on the climatic zone of the area of interest. Therefore, three major zones were identified: sub-arid regions (e.g. North of Nigeria), sub-tropical regions (e.g. Cameroon), tropical regions (e.g. Gabon).

In the following pages, different applications are briefly described with the help of the above criteria. These short descriptions aim at giving a flavour of what could be done with remote sensing, and readers are invited to test them for themselves. A subset of the applications has been chosen for more detailed image interpretation. This does not mean that those which are not explained in the later chapters cannot benefit from the use of ERS-SAR data, but rather that the results are perhaps less impressive than for the key applications selected. In addition, this publication does not aim to give a comprehensive picture (see literature list) of the application potential of ERS-SAR, but rather tries to help the user to identify the most useful data sources, the related interpretation methods and some potential results.

APPLICATIONS

1 Tropical and sub-equatorial forest management and deforestation evaluation

2 Rice Monitoring

3 Oil spill detection/Water pollution and ship detection

4 Lake Chad extension

5 Coastal environment of Guinea Bissau

6 Management of urban agglomeration

7 Pipeline: location and planning/environmental impact assessment

8 Map updating

9A Mapping and management of non renewable resources

9B Volcano monitoring in Cameroon and Zaire

10 Protection of mangrove forests and coastal erosion

All eleven of the forgoing applications are considered to be very important for Central African countries and ERS data can certainly provide very useful information. It was not possible to investigate all of them in detail, however, and therefore six were selected as being representative examples for more in-depth study. The areas investigated were located in different countries in order to demonstrate the usefulness of ERS-SAR for the whole Central African region.

1. Tropical forestry management in Gabon, the Congo and Equatorial Guinea (Application 1).

2. Agriculture (rice) monitoring in Nigeria (Application 2).

3. Hydrology and water resource management for Lake Chad in Cameroon (Application 4).

4. Cartography (including urban management) in Nigeria and Gabon (Applications 6, 8).

5. Geological cartography in the Central African Republic (Application 9a).

6. Mangrove forest management in Gabon (Application 10).

Those applications which are not described in detail in Chapter "Selected Interpretation Results" are, however, included in the general evaluation of the ERS-SAR application potential in the last chapter. More details about these applications can also be found via the bibliography in the Annex.