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The TopologyBuilder computes topology on input point,行,和/或区域特征。
Topologically significant nodes and lines are computed using all input features and output with additional attributes which describe the topological relationships.TopologyBuilder并不假定所有输入数据都是干净的,并且节点化正确。It takes any data and constructs the resulting topology after computing any intersections present in the input data.
It outputs the significant NODEs and LINEs with attributes describing their topological relationships.AREAs are output with information about the LINE edges which form them.
TheTopologyBuilder documentationhas detailed information on the various parameters which can be used to control the topology information which is produced.
该变压器通常用于确定拓扑关系,以帮助后期变压器的决策。
一组交通数据由公交路线和站点组成。The idea is to measure the length between each stop.The problem is how to obtain the ID from each stop and attach it to that section of route.TopologyBuilder为每个站点创建一个节点ID,after which FeatureMergers are used to match the node ID for stops/routes and thereby obtain the stop ID.The resultant workspace looks something like this:
As is often the case in FME there is often more than one approach to solving a problem.这个公交车站的问题也可以通过使用FME中的一些线性参考工具来解决,例如测量,NeighborFinderandSnipper&LengthToPointCalculator……
源数据是一组沿着单个总线路径的总线站点。The bus route is made up of line segments between each bus stop.所有参数均设置为默认值,未设置Group By。
Note:If we were processing a large number of bus routes it would be useful to add the route numbers to the bus stops such that the route number could be used in a Group By.这将大大加快处理速度。
Building topology adds a lot of extra attributes to the features that,depending on what further processing you are doing,may not be needed.如果不需要的话,最好将其移除。In this example we are only interested in the interaction between the lines and the nodes,而不是线条边缘,or node angle information.
The _node_number on the nodes can be linked to the _from_node and _to_node values on the line to extract the start/stop bus stops along the route.
最后,使用长度计算器计算站点之间的距离,并将新的总线路径信息写入mapinfo选项卡文件。
笔记:仔细观察输出,添加了一个额外的节点,其中总线路由在路由末端附近分成两个节点,因此,需要进行额外的处理来解决这些问题。
The "Assume Clean Data" parameter in the TopologyBuilder can be useful as in the following example.
用户拥有道路数据集,希望创建定义线和节点ID及其连接的网络属性。
The key issue is what happens at a bridge or overpass?In this screenshot (below) we see the source road is a complete line that passes over (and does not intersect) the street beneath:
After the transformation with TopologyBuilder,the network attributes are created (below):
……但不幸的是,线条在交叉处相交(如下所示):
使用“假设干净数据”选项可以防止不需要的数据清理(如下所示):
打开后,会得到正确的结果(如下所示):
The data is typically at the top of each tutorial.我附加了模板工作区和单独的数据:
Regards,
-Liz
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