Separate three different gaps
A service outage means the request could not be completed. A no-coverage response means the provider returned no usable map records for the point. An unrated component means a map record exists but the particular property is not reported. Retry can help the first problem; it does not create missing survey measurements.
Read the depth coverage
Our screening interval is the upper 100 cm. If reported linear-extensibility values cover 40 cm, the other 60 cm remain unrated. The visual depth strip shows the actual reported intervals rather than painting the whole profile with the highest available class. Overlapping intervals count once.
A mixed map unit needs a mixed answer
A dominant component may be unrated while another component has a reported value. The report keeps those components separate. It does not silently substitute the smaller rated component for the larger unknown one. A tied largest share or multiple intersecting map units also prevents a unique dominant selection.
What to do with the gap
First confirm the intended location. Review the original source and existing site documents. For a decision about a building, ask which site-specific investigation would fill the gap. Moving the pin until a lower class appears is not a reliable way to evaluate a property.
Sources and interpretation
Explanations and workflow are our own. This is educational screening, not a site investigation or engineering recommendation.