operating capabilities but also allows users to include functions and operations peculair to their classes of problems. These special functions or operations may in fact take the form of algorithms written and compiled in other system supported languages, such as FORTRAN, and simply linked into Speakeasy's processor. These linked load modules are called linkules. To the user linkules are a vocabulary of English language key words that allow the associated programs to be called and executed by name. During the development of RAGIS, an extensive number of linkules specifically related to napping and spatial analysis were established. In fact, RAGIS has become a subsystem within Speakeasy consisting of more 250 programs and special operations for geographic information processing. Data is encoded through the use of a CRT (Cathode Ray Tube). A data encoding linkule establishes a uniform grid of cells (64 x 48) as a two dimensional array across the CRT screen. Maps or other special features to be encoded are reproduced at the appropriate scale as black and white film positives. These film positives were taken from the 21 maps of the United States, with six individual 64 x 48 grid "cards" being required for each map to be encoded. The film positive is placed on the screen and the pattern of each feature is then visually coded in a raster-like fashion as a dot pattern. In this study, a feature was coded as either present or absent within the appropriate grid cell. Checking the encoded data is accomplished on-line at the CRT screen by simply displaying each dot pattern and checking it against the film positive overlay. The coded data is stored in the computer memory as a logical bit stream with each image forming a distinct binary pattern. This form of storage utilizes the computer's memory switches and results in considerable savings for basic storage, retrieval and display operations. Each data pattern is assigned a unique alphanumeric code or name and becomes like any other word in the system from the user's standpoint. Access is achieved by simply calling for the pattern by name and having
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