What does this error message mean: Operator '=' is not defined for the type DBNull and string "Stream Centerline" ? Does anyone know how I can fix this. Thank you

Question

I am using ArcMap and HEC-RAS to model the flood extent in Morpeth.

When trying to use the RAS Geometry-> Stream Centreline Atributes function the error message Operator '=' is not defined for the type DBNull and string "RiverWansbeck1" appears. RiverWansbeck1 being the stream centerline.

Does anyone know what this means and how I can fix it so it will work?

Thanks.

DanPatterson_Retired · Answer

Not sure what you are doing, but many times " = " an assignment statement (aka something is given the value of)

If it is a check for equality " == " is often used (aka is something equal to something else)

So your results need to be assessed in terms of assignment or equality checking for the language that is being used.

TedKowal · Answer

I am not a hydro or a hec user but the error code you are getting is a null value where it was not expected.  If you are reading from a dataset/database/FC One or more of the fields being used contains a null value.

If you are coding: You need and test to account for a null values.