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Dear Community,

 

I would have a few questions for CityGML building.

 

I have a SHP file with building polygons (roof, wall, groundbase), and I would like to build a proper cityGML file. I read over the whole forum and also CityGML specification, but there is no description, WHICH attributes MUST be defined in case to have a proper CityGML output WITH geometry.

 

In some of the forum topics here, there were good spots, and sample workspaces, which can be used to build simple buildings, but to build from SHP polygons, it's seems though for me.

I'm trying to build a LOD 2 model. I have my walls, roof, ground, and the whole thing aggregated together (So I have the exterior shell and parts separately) They all have unique parent ID per building, set LOD name, feature role, geometry type and other attributes, which I found set inside related questions in this forum. But when I run the translation, I always receive a data set with no geometry inside, if I try to build a proper building model from sides, using boundedBy role. If I use cityObjectMemer role, I can receive geometry, but for building parts, I must use boundedBy role according to my understanding. My best understanding about the issues is that, attributes are not coded properly to match the GML schema.

 

My questions are the following:

Where can I find a full list of "must have" attributes to be defined in order to have geometry output? I think I might miss a few must have attributes, that would be the reason to not receive geometry. CityGML Writer documentation does not provide answers. CityGML specification 2.0 neither.

Where can I find a manual, how to define connection between elements, and how to merge them properly in FME to receive a valid, geometry equipped output? In citygml, the outer shell shall be connected to the parts. I have the multisurface building as aggregated, and parts with the same parent ID, but I assume, other attributes need to be defined. I assume I might use wrong geometry type either.

If you can recommend any documentation, manual, etc. to better understand CityGML building in attribute level in FME, it would be also a great help. I think I ran out of the basic Google searches in the topic :)

 

Your help is highly appreciated. Thank you

Bálint

 

 

 

Hi @mbfoldmeres​,

I think the best place to start would be our CityGML Tutorial, but if you would like to share a sample of your Shape data, I would be happy to put together an annotated workspace to illustrate the processing needed to convert to CityGML.

Hi @mbfoldmeres​,

I think the best place to start would be our CityGML Tutorial, but if you would like to share a sample of your Shape data, I would be happy to put together an annotated workspace to illustrate the processing needed to convert to CityGML.

Dear @daveatsafe​ 

 

Thank you for your answer.

I could manage to build a kind of good workspace to create the CityGML file. However, I think it's not the most well organized one :)

I use FZKViewer to validate my results. For this, I could download a sample which has a hierarchy as the following:

imageI build my Workspace to have a Building, BuildingPart, RoofSurface, GroundSurface, WallSurface and BuildingInstallation layers, plus TINrelief and some textures.

My hierarchy looks like this:

imageWhen I created the CityGML, I used a SHP, where all sides of the building are defined as polygons. I connected the content (with using the required transformers) as follows:

  • The whole shp to Building writer
  • Separated roof, wall and floor elements to BuildingPart writer
  • Separated roof, wall and floor elements to the respective surface writers
  • RoofSurface writer is duplicated as the texture is required (Appearance Setter is the last transformer before the Writer)
  • TIN surface as textured to TINRelief writer (Appearance Setter is the last transformer before the Writer)
  • Structures over the roof (roof on roof and it's walls) in a separated line are connected to the BuildingInstallation Writer
  • BuildingInstallation Writer is duplicated as the roof section received textures.

In the provided hierarchy, I think under Building/CityGML BuildingPart, the bldg:BuildingPart level is not required, and my understanding is that, something is connected kind of double. Also, I'm not sure, if the genobj textures are in the proper hierarchy level. Also, in FME Data Inspector, to see the roof texture, I have to turn off roof geometry, so I assume, something is wrong there as well.

 

Can you please advise, how to create a properly organized hierarchy, and what to modify?

Unfortunately, I cannot share the workspace here.

Thank you for your help.

 

 

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