"Import culverts" processing algorithm

[leendertvanwolfswinkel]

Please read #119 first

I propose that before we implement the GUI, we make a processing algorithm that does the same thing. It would work like this:

Inputs

• Source layer
• Target 3Di Schematisation (GeoPackage file)
• Conversion configuration file (e.g. JSON) The JSON file could look something like this:

{
  "target_layer": "culvert",
  "conversion_settings": {
    "use_snapping": true,
    "snapping_distance": 0.5,
    "create_connection_nodes": true
  },
  "fields": {
    "id": {
      "method": "auto"
    },
    "code": {
      "method": "source_attribute",
      "source_attribute": "kdu_identificatie",
      "default_value": "duiker (kdu id onbekend)"
    },
    "display_name": {
      "method": "ignore"
    },
    "calculation_type": {
      "method": "source_attribute",
      "source_attribute": "kdu_open",
      "value_map": {
        "ja": "102",
        "nee": "101"
      }
    },
    "discharge_coefficient_positive": {
      "method": "default",
      "default_value": 0.8
    }   
  }
}

Outputs

• The resulting Culvert and Connection node features are written to the corresponding layers in the geopackage

Algorithm See #119

[leendertvanwolfswinkel]

I have tested this, using this example data: https://app.zenhub.com/files/481141268/b0b34642-e95b-48a8-9fbe-94bfbf5e6c82/download

Test results:

• It helped me debug syntax errors in my JSON file, which was perfect
• I had a lot of duplicate connection nodes
• No culvert features where added to the geopackage
• Map canvas is not repainted after the algo finishes, so it looks like nothing has happened

[ldebek]

Fixes applied.

[leendertvanwolfswinkel]

Great, I think the main things are there now. Some smaller issues (I hope):

• [ ] My config json includes create_connection_nodes in the conversion_settings, but if I set it to False, it will still create connection nodes
• [ ] If a source value is NULL, please use the default_value as fallback value. For example, if in the source data the value for afvoercoefficient is NULL and this is the config for discharge_coefficient_positive

  "discharge_coefficient_positive": {
    "method": "source_attribute",
    "source_attribute": "afvoercoefficient",
    "default_value": 0.8
  },

  the imported culvert should have a discharge_coefficient_positive of 0.8. Now it is NULL

[ldebek]

@leendertvanwolfswinkel Fixes for the above issues applied.

[leendertvanwolfswinkel]

Great! Let's merge this