WalkLite in Mobile GIS: A Schema to Extend and Symbolize SpatiaLite

Dr. X. Chenxianchen@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•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.

WalkGIS•A GIS platform 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• Traditional desktop-based system is somehow outdated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

1998 ~ 2013 2013 ~

Platform Windows only Windows, Linux, Android

Device Desktop Desktop, Mobile

Base library Walk Library Walk Library + GDAL/OGR

Graphical UI GDI+ GDI+, Skia

Built-in data formats

Walk MDB, SQL Server Spatial

Walk SQLite (WalkLite), Walk MDB, etc.

Vector data supported

Shapefile, AutoCAD dxf, Mapinfo

Data formats supported by GDAL/OGR

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-based mobile GIS App used in a number of Chinese provinces for:• Land investigation• Land use Planning• Cadastral inventory• Real estate analysis• …

WalkLite Applications

• 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

• 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

Future Work?

Questions?Questions?http://www.walkinfo.com/en.html