Africover interpretation software

Even if the whole Africover methodological approach is independent from the interpretation method used (e.g. Automatic versus Visual interpretation) and even if part of the countries in the Africover Eastern Africa module have been mapped using a visual interpretation, the experience gathered in those years of activities suggests the use of a combination of the two methods.

The most ergonomic approach consists in the use of a localized (or class specific oriented) automatic classification that can be interactively manipulated, modified and integrated by a on screen visual interpretation. To do this and to allow all the future potential users of the Africover methodology to perform this activity in a fast and user-friendly way two types of new software have been produced.

AIMS (Africover Interpretation and Mapping System) and GeoVIS (Geographical Vector Interpretation System) are “on-screen” interpretation software that combine the advantages of the digital automatic classification and the traditional manual (visual) interpretation.

Both were done to fill a gap on the existing commercial software. Most of them, in fact, are either digital image processing systems performing a number of automatic classifications but with very limited vector capabilities or systems designed to perform an on screen digitization with limited raster functions.

AIMs

AIMS has been the first system to be produced. It is derived from a core image-processing package updated with a series of vector based functionalities. It enables an interactive use of ancillary data by combining different types of data in geographically linked windows. In particular, the software will facilitate image analysis of a large number of optical as well as radar (SAR) satellite images.

Drawing of polygons and lines, cursor positioning, panning and zooming are done in a seamless way. The system will be able to produce map sheets at selected scales of countries with different cartographic systems. AIMS will be used for thematic enhancement of the database (when for instance the land cover layer must be updated with other thematic maps still on raster format) or when different remote sensing data must be used in the same time (e.g. Optical and Radar data in cloudy areas, images of different seasons or data with different spectral and spatial resolution etc.).

The major limitation of the system is that due to the format of the vector layer (basically a “spaghetti vector” with full export capability in shape file) the user must have a substantial knowledge of vector GIS when performing the interpretation. In addition a specialized GIS work will be needed in order to create the final “topological” database.

GeoVIS

GeoVIS is the latest software created. On the opposite of AIMS it has been developed starting from a vector based digitization software. Therefore has much more advanced vector functions for the on screen polygon digitization.

This makes the interpretation activity much simpler and reduces the GIS work to later build up the database. The major limitations are the limited raster functions (absence of automatic classification, geographically linked windows). However these limitations will be updated in the next version of the system.

GeoVIS is property of the Food and Agricultural Organisation of the United Nations and as such is available for download only for UN Agencies, organisations dealing with FAO and National institutions.