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NOAA-OWP / inundation-mapping

Flood inundation mapping and evaluation software configured to work with U.S. National Water Model.
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nwm_lakes.gpkg has some 3D features, all with z-value = 0 #464

Open dhardestylewis opened 3 years ago

dhardestylewis commented 3 years ago

nwm_lakes.gpkg has some 3D features, all with z-value = 0.

Current behavior

Data input nwm_lakes.gpkg in separate FIM3 dataset has some features with 3D values, however the 3rd z-dimension all have value 0. This can break some functionality of GeoPandas, for example outputting to FileGDB, which does not directly support 3D polygons.

I have not yet checked every FIM3 GPKG: others may be impacted.

Expected behavior

No extra information is provided by these 0-value z-coordinates, and these GPKGs are already fairly large. Ensuring these don't creep into input data can help reduce the overall size of provided inputs.

Steps to replicate behavior (include URLs)

  1. Open nwm_lakes.gpkg in any GIS application.
  2. Filter for 3D geometries.
  3. Return 3rd coordinate for each geometry.
  4. Return unique values for all 3rd coordinates.
  5. Determine that there is only 1 unique value for every 3rd coordinate: 0.

Screenshots

None needed.

BradfordBates-NOAA commented 2 years ago

@BrianAvant-NOAA Do you have any thoughts on this?

BrianAvant commented 2 years ago

@BradfordBates-NOAA I'm assuming those z-values are just carried over from whoever created the layer (probably NCAR). If we don't need them then we can remove them if we feel it is an issue.