How about leveling start from known point to unknown point and back to known point? known point here means the point where the height is knownNidum said:Levelling around a survey route from one fixed bench mark and back to the same bench mark provides a very reliable means of error checking . If the cumulative changes in elevation around the survey route amount to zero when you get back to the known bench mark then the probablity of having made measurement mistakes somewhere along the way is very small .
chetzread said:How about leveling start from known point to unknown point and back to known point? known point here means the point where the height is known
sorry , i mean how about levelling work start from a point where the height is known (benchmark) , and ends at a different point where the height is unknown ...Nidum said:That is effectively the same thing . You can designate any fixed level as your benchmark level .
When levelling over relatively short distances - on for example a construction site - the simpler method of starting from a bench mark and just proceeding in one direction is sometimes used .
Modern laser surveying methods and coming of GPS have made most of the traditional surveying methods obsolete .
Can you explain further ?Nidum said:That is effectively the same thing . You can designate any fixed level as your benchmark level .
When levelling over relatively short distances - on for example a construction site - the simpler method of starting from a bench mark and just proceeding in one direction is sometimes used .
Modern laser surveying methods and coming of GPS have made most of the traditional surveying methods obsolete .
Benchmark and temporary benchmark points are used to establish a known elevation for a specific location. This serves as a reference point for future surveys and construction projects, ensuring accuracy and consistency in the vertical measurements.
Benchmark points are typically established by government agencies or professional surveyors using precise leveling techniques. Temporary benchmark points can also be established by surveyors for specific projects, using methods such as differential leveling or trigonometric leveling.
The main difference is the longevity of the point's use. Benchmark points are typically permanent and have been accurately measured and recorded over time. Temporary benchmark points are used for shorter periods and may be removed or replaced after the project is completed.
Benchmark points serve as a reference for measuring elevations of other points in the same area. Temporary benchmark points can be used as a reference for specific projects, or to check the accuracy of existing benchmark points.
Some challenges may include locating benchmark points that may have been disturbed or destroyed, ensuring the accuracy of the measurements, and accounting for changes in elevation due to natural or man-made factors. It is important to properly document and verify all benchmark points used in a leveling procedure.