Which of the following is an essential characteristic of surface indications noted in a topographic survey?

In a topographic survey, an essential characteristic of surface indications is that they should be visible, obvious, and apparent. This visibility is crucial because topographic surveys primarily rely on the observation and measurement of features directly on the ground. When surface indications are clear and evident, it allows surveyors to accurately document the landscape's contours, elevations, and physical features, ensuring precise topographic mapping.

The ability to visually identify these indications enables surveyors to make reliable assessments about the terrain, which is essential for planning and development projects. When surveying, having obvious and apparent features simplifies interpretation and minimizes the risk of errors that could arise from ambiguity or misinterpretation.

In contrast, the need to infer these indications, rely solely on imagery, or employ vague descriptions would not support the precision required in topographic surveys. Clear and visible features strengthen the survey's reliability and integrity, making them a foundational aspect of topographic analysis.