Title: Topographic and Vegetation Maps, produced from high resolution Synthetic Aperture Radar

N° Project: B7-5041/92.12/VIII/FOR

Amount: 3.449.305 ECU

Contractor: INTERA Information technologies LTD (UK)

Field: Publication/cartography

Country: Regional (Afrique Central: Cameroon, Congo, Gabon, Equatorial Guinea, Central African Republic, Zaire, Nigeria)

Date of signature: 11/12/92

Duration: 28 months + rider until 30/09/97 (29 months extension).

To obtain data in persistent cloud covered areas, such are experienced in the Central African Regions. The radar imagery has been chosen as the most reliable way to use.

1. The first phase is to acquire high resolution (6 m pixel) SAR data over the 10 zones in Central Africa for a total f 80425 Kmē.
2. The second phase is to perform the processing of such data, including the production of topographic mapping products, and a pre-interpretation of the imagery for vegetation mapping at 1:50000 scale.
3. The third phase consist of compiling all imagery and field data to produce vegetation maps at 1:50000 scale.

Activities:

• Phase I : Data Acquisition; processing and production of strips;
• Phase II: Production of Ortho-image and contour line mapping products; Pre-interpretation base maps; Training program (20 days for a maximum of 20 persons) on radar imagery and its interpretation.
• Phase III: Vegetation maps

Results expected:

• Elaboration of Topographic and vegetation maps as a support for the ECOFAC Program, The E.C Joint Research Centre and the Nigerian Representation of EC
• Training program provided by the contractor to the ECOFAC and Nigerian users (ground truth people) on radar imagery and its interpretation.

Beneficiaries:

• DG VIII/D5 to produce a cartographic base for the ECOFAC PROGRAM;
• Joint Research Centre, Remote Sensing Dept. to calibrate AVHRR data for the TREES EC program;
• The Nigerian Delegation of the EC for the Cross River National Parks project.

Implementation procedure:

• Field work and ground truth survey . The contractor agrees to perform Synthetic Aperture Radar (SAR) surveys covering 10 national parks, forests and reserves, distributed in 7 countries of Central Africa.
• Training program provided by the contractor to the ECOFAC and Nigerian users (ground truth people) on radar imagery and its interpretation.

Final report. The project has been completed.

The radar imagery was chosen as the most reliable and timely data source for acquiring information in persistent cloud covered areas. SAR surveys were conducted of ten national parks, forests, and reserves in seven countries of Central Africa:

1. Dja Reserve (Cameroon);
2. Takamanda Forest Reserve (Cameroon);
3. Korup National Park (Cameroon);
4. Odzala Complex (Congo);
5. La Lope Reserve (Gabon);
6. Monte Alen Park (Equatorial Guinea);
7. Ngoto and Bodingue Forests (Central African Republic);
8. Salonga National Park (Zaire);
9. Oban Hill Section, Cross River National Parks (Nigeria);
10. Okwango and Afi River Reserve Section (Nigeria).

According with the objectives of the contract, the conclusions of final report underline that the program has successfully demonstrated that airborne SAR data can be used to provide up-to-date vegetation and topographic information for areas that might otherwise have remained unmapped by conventional optical means due to the persistent cloud cover in the area concerned. Moreover some delays (Final Vegetation Base Map Production activities) were created by an inability to communicate with some of the parks or reserves.

Products and services from this project were delivered to three client group:

1. ECOFAC Programme;
2. The Joint Research Centre Remote Sensing Dept. to calibrate AVHRR data for the TREES E.C. programme;
3. The Nigerian Delegation of the EC for the Cross River National Parks project.;.

A training programme including theory of SAR, acquisition of SAR data, processing of data, image analysis and practice sessions, was carried out in October 1993 in Libreville. Maps produced by the participants were reviewed and critical feedback was given by their peers and trainers.

The results of the field verification (III) programme were varied depending on local conditions and the ability of field personnel to respond of updating and editing preliminary maps. The field activities were the responsibility of the administration of each park and reserve. Delays to the delivery schedual were created by an inability to communicate with some of the parks or reserves.