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WalkLite in Mobile GIS: A Schema to Extend and Symbolize SpatiaLite. Dr. X. Chen xianchen@walkinfo.com.cn Walkinfo Tech. Co. Ltd. Background. WalkGIS A GIS platform as of 1998 Complying with OGC standards Representing vector and raster geospatial data by Walk schema
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WalkLite in Mobile GIS: A Schema to Extend and Symbolize SpatiaLite Dr. X. Chen xianchen@walkinfo.com.cn Walkinfo Tech. Co. Ltd.
Background • WalkGIS • A GISplatform as of 1998 • Complying with OGC standards • Representing vector and raster geospatial data by Walk schema • Providing a C++-like script language for customization • A family of GIS products: WalkSurvey, WalkISurvey, WalkIOffice, WalkFloor, WalkCheck, WalkFU, etc. • Originally designed for land survey in China, now widely used in land use investigation & planning, house property, transportation, population, etc.
Problems in 2013 • Traditional desktop-based system is somehow outdated • No application can be run on mobile devices • End users limited in specific areas • Difficulties encountered when translating various geospatial data
WalkGIS Migration From Windows to Cross-Platform
WalkLite • Walk schema applied in SQLite/SpatiaLite: • Adapting OGR SQLite driver • Defining four meta-data tables: WalkLayers, SymbolFactory, MetaData, and MetaDataDef. • Each WalkLite layer corresponding to three tables: • Features • Symbols • Annotations (text annotations, raster and vector tiles)
WalkLite Layer • WalkLite features: OGR SQLite layer containing • OGC SRS geometry • OGC Feature ID and Walk Feature ID • Createtime: Time of the feature creation • Style ID: Symbol ID for feature style • Feature attributes • SpatiaLite is used for spatial index
WalkLite: Annotations • WalkLite annotations: OGR SQLite layer containing • OGC SRS geometry • Points for the location of text annotations • Polygons for the location of tiles • OGC Feature ID and Walk Annotation ID • Annotation: Text that stores the content of annotation or the file path of tile (Format supported by GDAL) • Style ID: Symbol ID for annotation style • SpatiaLite is used for spatial index
WalkLite: Symbols • WalkLite symbols: regular SQLite table • Styles ID referred by the features and annotations • Style: BLOB data serializing the symbol style • Style name and note
Advantages of WalkLite • Cross-platform: No data translation required between mobile application (data collection) and desktop application (data processing) • One schema for both vector and raster data, also map styling • Comparatively fast by using SpatiaLite index
WalkLite Applications • WalkLite-based mobile GIS App used in a number of Chinese provinces for: • Land investigation • Land use Planning • Cadastral inventory • Real estate analysis • …
Future Work? • Cross-platform SDK • Supporting iOS • WalkLite driver in GDAL/OGR [ODBC-based Walk driver already in GDAL/OGR (version >=1.10.0)] • Further improving and optimizing the performance of WalkLite data
Questions? http://www.walkinfo.com/en.html