Enriched geometric simplification of linear features
Polyline geometries are used to represent linear features, such as roads, rivers and pipelines on maps. The generalization process results in a polyline that represents the feature either at a different resolution or different scale from the original geometries. In addition, the simplification process may result in losing the geometric properties associated with the intermediate points on the original geometries. These intermediate points can contain attributes or characteristics depending on the application domain. For example, points on the road network can contain information about accumulated length of the road, positional velocity, speed limit or accumulated gas consumption. This paper involves implementing the SELF (Semantically Enriched Line simpliFication) data structure to preserve the length attributes associated with individual points on actual linear features [Stefanakis 2015]. The number of points to be stored in the SELF structure is optimized by applying alternative compression techniques. The data structure has been implemented in PostgreSQL 9.4 [2014] with PostGIS [2016] extension using PL/pgSQL to support static and non-functional polylines. Extended experimental work has been carried out to better understand the impact of simplification on both synthetic and real (natural and artificial) linear features such as rivers and pipelines. The efficiency of SELF structure with regard to geo metric property preservation has been tested at various levels of simplification.