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Introduction to the ALES Program

The Automated Land Evaluation System, or ALES, is a computer program that 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 ALESare 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). Since each model is built by a different evaluator to satisfy local needs, there is no fixed list of land use requirements by which land uses are evaluated, and no fixed list of land characteristics from which land qualities are inferred. Instead, these lists are determined by the evaluator to suit local conditions and objectives.

To reiterate the key point:

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.

The program is highly interactive, and takes advantage of the PC video display and keyboard. It is designed to be self-explanatory, and leads the user through a series of menus, data entry forms, 'why?' explanations, and dialogues, as well as context-sensitive help screens. Function keys control most operations.

The program user can choose to interact with ALES in any human language to which the display text has been translated:

in addition to English.

Special attention has been given to the creation, editing, and display of decision trees, which are the way in which the evaluator express expert knowledge about the relation between land and land uses In addition, model builders can write their own notes ('annotations') that can be displayed by the model user to explain the model builder's reasoning.

ALES runs on almost any Intel/DOS-compatible PC. Click here to see ALES' System Requirements.

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Last Updated: 2010_307

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