Hi,
`Borehole.boreholeLength` is using the stereotype `voidable` according to the implementing rules and the [UML model](https://inspire.ec.europa.eu/data-model/approved/r4618-ir/html/EARoot/EA2/EA2/EA2/EA1/EA7713.htm).
In the [xsd](https://inspire.ec.europa.eu/schemas/ge-core/4.0/GeologyCore.xsd), it is defined using the `swe:QuantityPropertyType` and no additional attributes which leads to the fact that no `nilReason` attribute can be provided for `Borehole.boreholeLength`.
Is there a reason not to use a type extending the `swe:QuantityPropertyType` with an additional `nilReason` attribute for the boreholeLength element?
Thank you and all the best
Johanna
Dear @JohannaOtt,
no, there is not, it seems that the `Borehole.boreholeLength` attribute is not encoded correctly.
I will move the issue to the schema repository since the encoding should be fixed.
The current encoding:
```xml
<element name="boreholeLength" nillable="true" type="swe:QuantityPropertyType">
<annotation>
<documentation>-- Definition --The distance along a borehole.-- Description --This
will be determined by the data provider (ie, "length" can have different sources,
like drillers measurement, loggers measurement, survey).
</documentation>
</annotation>
</element>
```
should be replaced by the following:
```xml
<element name="boreholeLength" nillable="true">
<annotation>
<documentation>-- Definition -- The distance along a borehole. -- Description -- This
will be determined by the data provider (ie, "length" can have different sources,
like drillers measurement, loggers measurement, survey).</documentation>
</annotation>
<complexType>
<complexContent>
<extension base="gml:AbstractMemberType">
<sequence>
<element ref="swe:Quantity"/>
</sequence>
<attribute name="nilReason" type="gml:NilReasonType"/>
</extension>
</complexContent>
</complexType>
</element>
```
As shown in the figure below, the new encoding (on the left side) allows the provision of the nilReason.
