My question is how to test each element in one list with each element in another list? I have lot of lines segments and using lengthCalculator to find all segments less than some specific length. Further with help of TopologyBuilder I get 'to_node' attribute related to LINE output port and 'node_number' related to NODE output port. I have to detect all dangles. So I am trying to test if there is a "node_number =! to_node" If so, then I know at this segment is dangle. Agree? for this I used transform Tester again, but this is not working. My next idea is to create list of all nodes and another list of all segments < specific_length, and then check (test) each node element in one list with to_node element in teh second list. Will this work? Not good idea?
This question is linked to: Find dangling lines .
Tnx
[GIS] How to test list elements in FME
fme
Related Solutions
Most simple way is do an OR test with your tester. Set the test criteria to "OR" And then set a test for each attribute value For example: OR areaID=1253 areaID=1254 areaID=1255 areaID=1304 etc
You can use LineJoiner transformer with parameter List Name. But you need to do some additional data processing:
- Use
LengthCalculatorto calculate lengths. - Use
Sorterto sort your lines by length (numeric sort, descending). - Use
LineJoinerto join lines. The biggest ones first (thanks to step 2). Specify parameterList Nameof theLineJoiner- some name for new list attribute. - Use
ListIndexerwith list index 0 - to get the first joined feature (the biggest one) attributes' from the list.
Here is how it will look:
EDIT1:
In order to be able to join only <1m features to bigger ones we need additionally to use:
Testertransformer after LengthCalculator with test:_length < 1- Use
SpatialFilter(tests to perform parameter:TOUCHES) after Tester to filter only that features which touch features <1m. Then perform line joining on them together with <1m features. Features that don't touch <1m, direct to output (or further processing).
Model:
EDIT2:
If you have <1m line that touches two big ones then they all will be joined together. If such case (<1m feature touches two or more big ones) is possible in your data then you should add some processing of such cases. Take a look at parameters Merge Attributes and Attribute Prefix of transformer SpatialFilter. Using these parameters you should be able to detect such cases and then do some additional filtering.
EDIT3:
Let's solve the case when you have two big lines touching one small (<1m). We need to take only one of the big lines to participate in joining with small one.
In order to be able to perform such filtering we need to mark these two big features with some id from small one they are touching. As stated in EDIT2, it can be done in SpatialFilter transformer using parameters Merge Attributes and Attribute Prefix.
Then use transformer DuplicateRemover to filter such duplicate features (two big) and take only one of them.
Hint: try to use Inspector transformer during creating your model and view intermediate results in any case that is not clear to you. In such way you will better understand how each of the transformers are working. Experiment with your data! :)
Best Answer
My first thought is to create a custom transformer with a loop in it.
Create an attribute (x) to act as a loop counter. Use the ListIndexer with that attribute to extract the values of the list for entry number x. Then compare them to the actual values with the Tester.
You'll want to make sure you don't overwrite the actual attributes by giving them different names to the ones you fetch from the list.
A ListElementCounter will tell you how many entries there are in the list, so you can increment X and test if it is equal to the list count. If so, that's when you exit the transformer.
Surprisingly (because it is a common operation) I can't find an example of this online; but you can read more about custom transformer loops on FMEpedia.