Some Considerations to Improve the General Feature Model and General Portrayal Model in Gittok

Abstract. The general feature model (GFM) and the general portrayal model (GPM) are defined in the geospatial information technology learning assistance tool called gittok. This paper introduces five proposals to integrate different types of features and associations in the GFM and GPM: 1) the extensional-schematization procedure enables to formulate application schemata by specifying its extension, that is, every object that falls under the screening guideline; 2) nongeographic feature type may be included in the application schema; 3) feature association type can be geographic or nongeographic in a similar way as feature type; 4) nongeographic features and/or associations can be represented as a one-dimensional map or list; 5) representation by the copy of the portrayal declaration associating with a super feature type to avoid duplication should be possible. These proposals will expand the discipline of geospatial information technology (GIT).