Question

An ArcGIS user is working with a CAD polyline feature class. It is comprised of a Feature_Type field containing water main features and a RefName field, which may contain a valve type or may be NULL. How can tins user build a query to isolate Water Main features containing a valid valve type?

A. "Feature_Type" = 'Water Mains' AND "RefName" < > 'Null'
B. "Feature_Type" = Water Mains AND "RefName" NOT Null
C. "Feature_Type" = 'Water Mains' AND "RefName" IS NOT Null
D. "Feature_Type" = 'Water Mains' AND "RefName" < > IS Null

Answer 1

This query selects Water Main features with a valid valve type by checking that the "Feature_Type" is 'Water Mains' and the "RefName" is not NULL.Thus,the correct option is c.

Step-by-step explanation:

In ArcGIS, the correct query to isolate Water Main features containing a valid valve type is option C. The query checks two conditions using the AND operator. First, it ensures that the "Feature_Type" is 'Water Mains,' and second, it checks that the "RefName" is not NULL using the "IS NOT Null" condition.

Now, let's break down the components of the query:

- `"Feature_Type" = 'Water Mains'`: This part ensures that only features with "Water Mains" in the "Feature_Type" field are considered.

- `"RefName" IS NOT Null`: This condition filters out features where the "RefName" field is not NULL. In other words, it selects only those Water Main features that have a valid value in the "RefName" field.

The combination of these conditions ensures that the query isolates Water Main features with a valid valve type. It's crucial to use "IS NOT Null" instead of the inequality operators ("<>" or "NOT") when checking for NULL values in ArcGIS queries.

In summary, option C provides an accurate and comprehensive query for the given task, making it the correct choice for isolating Water Main features with a valid valve type.

Therefore,the correct option is c.