Question

HTTPCaller: request WFS with bbox source parameters from other WFS

  • 21 August 2017
  • 4 replies
  • 28 views
S

I would like to be able to make a WFS- (HTTPCaller-)request within a variable bbox-area. These variable bbox-parameters represent municipality-areas.

Currently my worfklow looks like this:

In my current workflow I make a request to a WFS-service containing municpality names and boundaries (not included in the screenshot). Next I make use of BoundsExtractor and AttributeWriter to store these bbox-values.

Next, I have a CSV-file containing all of my WFS-requests (FeatureReader3)

For instance:

ID,URL

1;https://geoservices.informatievlaanderen.be/overdrachtdiensten/GRB/wfs?version=1.1.0&request;=GetFeature&maxFeatures;=1000&StartIndex;=1&typename;=GRB:GBG&outputformat;=application/json

What I would like to do is to join URL from above (FeatureReader3) with the BBOX-values coming form FeatureReader4. Ultimately my request should look like:

https://geoservices.informatievlaanderen.be/overdrachtdiensten/GRB/wfs?version=1.1.0&request;=GetFeature&maxFeatures;=1000&StartIndex;=1&typename;=GRB:GBG&outputformat;=application/json&bbox;=[parameters coming from FeatureReader4].

For now I have tried to use the StringConcatenator to join these values, without luck...

4 replies

redgeographics
Rank
Userlevel 5
Badge +25

The StringConcatenator sees them as 2 seperate features, if you use a FeatureMerger before it you can join them up to a single feature and then do the StringConcatenator.

If you're only processing a single request at a time you can set the FeatureMerger like this:

takashi
Rank
Userlevel 2
Badge +17

Hi @sdv, I think you can connect the FeatureReader_4 and the FeaturReader_3 in series and use the feature output from the FeatureReader_4 as the initiator for the FeatureReader_3. To merge the attributes of the initiator and resulting features, set "Merge Initiator and Result" to the Accumulation Mode parameter.

By the way, is there any specific reason for writing and reading the bbox-values temporarily with the AttributeFileWriter and FeatureReader_4? If there wasn't any reason, I think this workflow could also be possible.

... -> AttributeCreator (create bbox-values) -> FeatureReader_3 (read ID and URL) -> StringConcatenator (create an HTTP request parameter string) -> HTTPCaller -> ...

S

Hi @sdv, I think you can connect the FeatureReader_4 and the FeaturReader_3 in series and use the feature output from the FeatureReader_4 as the initiator for the FeatureReader_3. To merge the attributes of the initiator and resulting features, set "Merge Initiator and Result" to the Accumulation Mode parameter.

By the way, is there any specific reason for writing and reading the bbox-values temporarily with the AttributeFileWriter and FeatureReader_4? If there wasn't any reason, I think this workflow could also be possible.

... -> AttributeCreator (create bbox-values) -> FeatureReader_3 (read ID and URL) -> StringConcatenator (create an HTTP request parameter string) -> HTTPCaller -> ...

thanks takashi !

 

takashi
Rank
Userlevel 2
Badge +17

Hi @sdv, I think you can connect the FeatureReader_4 and the FeaturReader_3 in series and use the feature output from the FeatureReader_4 as the initiator for the FeatureReader_3. To merge the attributes of the initiator and resulting features, set "Merge Initiator and Result" to the Accumulation Mode parameter.

By the way, is there any specific reason for writing and reading the bbox-values temporarily with the AttributeFileWriter and FeatureReader_4? If there wasn't any reason, I think this workflow could also be possible.

... -> AttributeCreator (create bbox-values) -> FeatureReader_3 (read ID and URL) -> StringConcatenator (create an HTTP request parameter string) -> HTTPCaller -> ...

This screenshot illustrates my intention described in the previous post. The StringConcatenator can be removed if you set the "boundingbox" to the Query String parameter in the HTTPCaller.

 

 

 

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