基于PostGIS的线要素空间聚合方法

Polyline Spatial Aggregation Method Based on PostGIS

针对当前常规方法线空间流量数据聚合效率低的问题,提出基于PostGIS的流空间线要素聚合方法。通过离散化所有的线为点集,建立点集的空间索引,计算点集的唯一点集,对唯一点集上的每个点累加所有与该点重叠的属性值并进行更新,根据点的序列号和上一步更新的属性值,重新连接该条线上所有的点,在属性值变化处进行打断形成新的线要素。在此基础上,去除空间重叠的线要素和图形为空的线要素得到最后的线聚合结果。实验结果表明,该方法以矢量数据形式输出的线聚合结果正确,提取速度显著提升,有效地解决了大量矢量线数据融合时常规方法效率低下的问题。

To address the low efficiency of the existing methods for polyline spatial flow data aggregation,this paper proposes a method for polyline aggregation based on PostGIS.All polylines are discretized into a point set,for which a spatial index is established and the unique point set is calculated.For each point on the unique point set,all the attribute values of the points that overlap with the point are accumulated and updated.According to the sequence number of the point and the updated attribute value,all points on the line are reconnected.The line breaks where the attribute value changes to form a new polyline feature.Finally,all the spatially overlapping polyline features and the line features with empty graphics are removed to obtain the ultimate polyline aggregation result.The experimental results show that the polyline aggregation result output by this method in the form of vector data is correct,and the extraction speed is significantly improved,which effectively solves the low efficiency of the conventional methods for massive vector line data fusion.