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How can I pull Geometry data (CityGML) from an online database into my FME workspace for an adjustable selection area?


The mentioned database is available under the following url: https://www.opengeodata.nrw.de/produkte/geobasis/3dg/lod2_gml/lod2_gml/ . According to a very brief documentation the database is provided as an ATOM Download-Feed. But unfortunately I don't understand how to handle it in FME and will appreciate any advise.

 

Best regards

Alex

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Best answer by daveatsafe 8 April 2022, 23:39

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Hi @mralex007​,

The LoD tiles are 1000m * 1000m, with the lower left corner specified in the tile name.

So the tile LoD2_32_280_5657_1_NW.gml would have its lower left at 280000, 5657000 in the coordinate system EPSG:25832.

The easiest way to get the data is to reproject your selection polygon to EPSG:25832 (if needed), scale it by 0.001, then round the coordinates to 0 decimal places. Extract the coordinates as a list - each unique coordinate will specify a tile to download to cover the original selection.

You can use the FeatureReader transformer to read a CityGML dataset directly from the URL of the tile. You will need to set the reader parameter Reader Driven by CityGML Schema to No, however.

Hi @mralex007​,

The LoD tiles are 1000m * 1000m, with the lower left corner specified in the tile name.

So the tile LoD2_32_280_5657_1_NW.gml would have its lower left at 280000, 5657000 in the coordinate system EPSG:25832.

The easiest way to get the data is to reproject your selection polygon to EPSG:25832 (if needed), scale it by 0.001, then round the coordinates to 0 decimal places. Extract the coordinates as a list - each unique coordinate will specify a tile to download to cover the original selection.

You can use the FeatureReader transformer to read a CityGML dataset directly from the URL of the tile. You will need to set the reader parameter Reader Driven by CityGML Schema to No, however.

Thank you very much for the helpful answer! My model is finally working.

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