18 Questions
What is a method to make temporary survey points visible in a valley?
Erect tall flagged poles in a valley
How can cairns or tall flagged poles be surveyed for accurate location?
By GPS compass resection
What precision can be expected while using a basic GPS unit on the ground?
10-5 meters
Why is it important to note the precision of a location obtained using GPS?
To understand the reliability of the GPS data
How has the science of photogrammetry evolved in map-making over time?
Advanced with digital imagery and GIS processing
What has replaced the traditional complex graphical methods in air photography?
Digital imagery with PC-based GIS processing
What is the recommended angle for back-bearings to intersect the fence or other linear feature for the best results?
90°
When is compass resection typically used?
In rough, steep, boggy terrain or for long distances
Which of the following is NOT a feature suggested for taking compass bearings during compass resection?
Highways
What should be done if the triangle formed by intersecting bearings during compass resection is less than 1 mm across?
Take its center as the correct position
Why is it suggested to choose landmarks for compass resection that result in intersecting back-bearings between 60° and 90°?
To ensure ideal intersections that are seldom possible
What should be done if after checking bearings and plotting, there is still a triangle formed during compass resection?
Sight a fourth point if available
What is the purpose of adjusting a mirror compass for the grid magnetic angle?
To determine the angle between the orienting arrow and the orienting lines
How accurately should a geologist be able to pinpoint their location on a map according to the text?
Within 10 m
What method can be used to fix a point on a British 1:10 000 map, according to the text?
By resecting from known points
What is the purpose of temporary cairns mentioned in the text?
To provide additional points for resecting from
On maps of poorer quality, what additional effort might be required by a geologist according to the text?
Spending time surveying a network of cairns and useful points
What does the term 'resecting' mean in the context of location finding on maps?
Using prominent landmarks to fix points
Learn about the use of temporary survey points in valleys and the application of Global Positioning System (GPS) for accurate positioning. Discover how to utilize cairns or tall flagged poles for surveying purposes.
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