Shapefile vs GeoPackage tradeoffs in new standard based on CDB 11/10/2018 GAJ Geospatial Enterprises LLC

GAJ Geospatial Enterprises LLC Shapefiles are currently use in all CDB datasets to define vector information CDB Layers defined by vector datasets 100_GSFeature 101_GTFeature 102_GeoPolitical 201_RoadNetwork 202_RailRoadNetwork 203_PowerLinenetwork 204_HydrographyNetwork 400_NavData 401_Navigation 11/10/2018 GAJ Geospatial Enterprises LLC

GAJ Geospatial Enterprises LLC Each of these layers may have multiple components requiring different representations I.E. 201_RoadNetwork has a lineal features selector as well as a point feature selector I.E. 204_HydrographyNetwork has a lineal features selector as well as an areal feature selector Each of these representations requires a separate Shapefile set consisting of a .shp file a .dbf file and a .shx file in CDB. In CDB we are eliminating the .prj file which contains the projection information since by definition we define CDB as being WGS84 Latitude / Longitude (EPSG:4326). In eliminating the .prj file however the Shapefile can not be processed by many applications that require projection to be included with the Shapfile. 11/10/2018 GAJ Geospatial Enterprises LLC

GAJ Geospatial Enterprises LLC Shapefile Summery In the current CDB specification for each tile we have up to 3 files per Component Selector 2 as defined on page N-72 of the “CDB Specification – Appendices – V3.0” There a 20 Component Selector 2 values defined in the appendix. Since some of the Component Selector 2 selections point to attribute only selectors with no geometry component for a fully populated dataset we would have 40 (best case) to 60 worst case files depending on the software used to create the database. 11/10/2018 GAJ Geospatial Enterprises LLC

GAJ Geospatial Enterprises LLC GeoPackage The GeoPackage standard allows us to use multiple layers in a single file unlike Shapefiles which require multiple files per layer. This would allow us to have one vector file per CDB tile replacing 40 files required in the 3.0 specification. Layer Names can follow current CDB specification. Open Source GeoPackage implementations area available with non restrictive licenses such as the MIT license. The Geospatial Data Abstraction Library (GDAL) provides this functionality for both Shapefiles and GeoPackage datasets. 11/10/2018 GAJ Geospatial Enterprises LLC