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这篇文章也是教程的一部分我该怎么做,在FME|Next: Polygons Within Distance of Selected Features
When assessing spatial relationships a common scenario is finding out whether one feature is within X distance of another feature; for example is there a fire station/hall within 5km of a planned fireworks factory!
FME has several transformers that assess spatial relationships when features physically overlap (inside, outside, intersect, match, etc) but no specific transformer to find relationships within X distance.
Therefore the solution is to create a buffer of X distance around one of the features and then carry out a standard spatial overlay of the two datasets.
这个例子的第一个数据集源是表示是除雪路线的道路一组线(在SpatiaLite数据库);即,在冬季有停车限制,这样的雪可以更有效地清除道路。
The second dataset (in GML format) is a set of point features that represent addresses.
该数据集是这样的FME数据检查:
这里的情况是,这些特性对于销售,并为市政GIS团队的一员,我们要告诉潜在买家如果财产是25米除雪路线之内。
1. Start FME Workbench and begin with an empty canvas.
Select Readers > Add Reader from the menubar.
Set the data format to SpatiaLite. Select the attached sl3 file as the source dataset.
2. Again, select Readers > Add Reader from the menubar.
This time set the data format to GML (Geography Markup Language). Select the attached GML dataset as the source.
3. To find if one of these features is within 25 metres of another requires the creation of buffers around one set of features. So, add a Bufferer transformer. Connect it to the snowremovalroutes feature type:
Open the parameters dialog. Set the buffer amount to 25. The units do not need to be specified; they are taken from the units of the current coordinate system.
4. Add a SpatialFilter transformer. Connect the Bufferer:Buffered port to the SpatialFilter:Filter port. Connect the HouseInquiries feature type to the SpatialFilter:Candidate port:
Open the parameters dialog. Set the "Tests to Perform" parameter to carry out the testContains.
This will now assess whether each candidate (property address) is contained by the buffered area of a snow removal route. Features that pass the test must fall within such a buffer and so are within 25m of a snow removal route.
5. Add some Inspector transformers and run the workspace. By inspecting (and setting the symbology of) the output, you can see that the procedure has successfully picked out which addresses are (and which are not) within 25 metres of a snow removal route:
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