The Conversion Of HPD Chart Database Point Symbol To GIS Platform

Maritime Safety Administration of the People's Repulic of China in order to adapt to the development of information technology and improve the efficiency of the production needs of the chart,in 2007 the introduction of the CARIS HPD product hydrographic database system.With the development of shipping companies,port authorities,maritime bureau will need to HPD source data in the database and other hydrographic data(such as aerial survey data and DWG data,etc.)superimposed on the GIS platform display.The HPD chart system does not consider the sharing of the chart data in the design,which leads to the fact that the data of the HPD chart system can not be superimposed on the same platform with other chart data.The vector symbol HPD chart database symbols by lifting stroke is described,and the various symbols of the GIS platform is the TrueType font symbol,so the HPD chart database symbols to convert TrueType format symbol has very important research significance.This paper studies the process to consult the documents provided by the CARIS company,analyzes the structure of vector data symbols HPD chart database.Review of relevant literature at home and abroad,analyzes the data structure of TrueType font file.By inserting the font symbol in empty files of different font file,insert table change contrast method before and after the symbol font file descriptor table,the study of TrueType font file description table record data,in order to grasp the storage structure of TrueType font file.This paper studies the structure of vector data symbols HPD chart in the database,read the symbols HPD chart database in the color information and the stroke information.By studying the vector data structure of the TrueType font file,the HPD chart database is organized into TrueType font file.The TrueType font files and empty file caret after the description of change table table item,the Glyf table,Cmap table,Loca table,Head table,Maxp table,Hhea table,Hmtx table and OS/2 table record data Type,master the storage method of TrueType font file.According to the number of dimensions of nature chart symbols,custom chart symbols TrueType font file,and insert chart symbols after conversion.Using the ArcGIS Engine development kit,the converted HPD chart database point symbol is displayed on the ArcGIS platform,and presents a method of converting HPD chart symbols into GIS platform by vector method in TrueType format.