Constructing the symbol association tables for different mapping standards is the basis of the symbol standard conversion.
To recognise a symbol, a pixel-by-pixel matching approach is proposed in which the symbols in a map, and those in the symbol library with the same mapping standard, are firstly transformed into BMP images, and then the symbol images within the map are matched with images from the library, to find out the correct symbol.
For instance, in the petroleum industry, various map standards are used, i.e. the Dutch Shell standard, the United States Geological Survey (USGS) standard and the Chinese Petroleum standard: as such, the "oilfield" object is symbolised differently (Fig. 1).
A novel approach for symbol recognition and automatic conversion is proposed, and according to the approach, based on the ArcGIS Engine platform and the integrated development environment of Visual Studio 2010, a conversion system for a vector map standard is developed by using component object model (COM) technology.
While basic procedures such as process mapping and standards are mentioned, focus will be on deterministic and probabilistic, descriptive and prescriptive, mathematical and computational models as well as new paradigms in system design.
The basic data for the conversion of a map among three petroleum standards are mainly the mapping specifications and symbol library files of the three standards, symbol association tables, and a map based on a standard.
All these validators check if the rules specified in the mapping file for the respective standards are fulfilled by a given instance data file.
Each symbol used in the map can thus be converted, and symbol standard conversion between different mapping standards can be realised.
Based on this idea, the corresponding relationship between symbol codes (names) in different mapping standards can be established, and then the mutual conversion of symbols between different standards can be realised by using the established relationship.
Firstly, the corresponding relationship between symbols in different mapping standards should be constructed according to the symbol codes (names).
