Automated Land Evaluation System

Automated Land Evaluation System - ALES

The Automated Land Evaluation System, or ALES, is a land information system which allows countries to determine the crops which are physically and economically best suited to their respective land units. ALES allows land evaluators to build expert systems to evaluate land according to the method presented in the Food and Agriculture Organization "Framework for Land Evaluation" (FAO 1976). It is intended for use in project or regional scale land evaluation. The entities evaluated by ALES are map units, which may be defined either broadly (as e.g. in reconnaissance surveys and general feasibility studies) or narrowly (as e.g. in detailed resource surveys and farm-scale planning).

ALES' function is basically to match the land attributes to crop requirements and to determine the most suitable options for land use, including in the analysis socio-economic variables such as cost. ALES is being piloted in three Eastern Caribbean countries

Evaluators build their own expert systems with ALES, taking into account local conditions and objectives. ALES is not by itself an expert system, and does not include by itself any knowledge about land and land use. ALES is a framework within which evaluators can express their own, local, knowledge.

ALES has seven components:

1. a framework for a knowledge base describing proposed land uses, in both physical and economic terms;
2. a framework for a database describing the land areas to be evaluated;
3. an inference mechanism to relate these two, thereby computing the physical and economic suitability of a set of map units for a set of proposed land uses;
4. an explanation facility that allows model builders to understand and fine-tune their models;
5. a consultation mode that allows a casual user to query the system about one land use at a time;
6. a report generator (on-screen, to a printer, or to disk files); and
7. an import/export module that allows data to be exchanged with external databases, geographic information systems, and spreadsheets. This includes the ALIDRIS interface to the IDRISI geographic information system as well as an interface to xBase (dBase III+) - format database files, including Attribute Tables in PC-Arc/Info

ALES is not a GIS and does not display maps. It can, however, analyze geographic land characteristics if map units are appropriate defined, and it can directly reclassify IDRISI maps or Arc/Info Attribute Tables with the same mapping unit legend as the ALES database.

Given its characteristics, ALES is a good candidate for being used as a decision support system for sustainable land-use purposes. Due to its flexibility, environmental and socioeconomic attributes that are considered to be important for sustainability could be used to define desirable land qualities. The definition of the appropriate data for estimating sustainability to be collected and input into the system would be the main challenge left to overcome.

For more information on ALES:

Cornell University's ALES Home Page. Contains detailed information and history of the ALES system and on land evaluation methods in general, as well as useful links. http://www.css.cornell.edu/landeval/ales/ales.htm

Also see Presentation on Managing Information for Decision-making in Land Use Planning - Automated Land Information System (ALES), by Glynis Ford, FAO/Ministry of Agriculture of Jamaica. Additional materials are available on the IDSD Training Workshop page.

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