Why is it that when surveyors measure the height of a mountain, they should use the horizontal plane

Because there's a benchmark for everything. Most of the earth is seawater, and many valleys, basins, flatlands, grasslands, and so many valleys, basins, flatlands, grasslands, and so many grasslands in the world are often very large, and there are so many valleys, basins, flatlands, grasslands, or something in the world. Come to think of it, the sea is not flat, but the sea is the best, so it seems like that's it.

I didn't find any professional knowledge, so I had to talk about it myself.

Because the water is relatively flat, that's why we have to talk about the principle of a bowl of water being flat!

It should be the level from sea level to the top of the mountain, right?

Summary. 1. The projection method is to measure the vertical projection area, and the change of height does not affect the measurement results. In fact, it is the map plane measurement, which is simple and accurate.

2. The surface method is to actually measure the surface area of the mountain, which should be measured piece by piece, and then summarized to obtain the total area. This method is more cumbersome, but it can reflect the real area used, and it is fair for those that are mainly planted.

The area of a mountain needs to be determined, what methods can be measured? How should each method be measured?

1. The projection method is to measure the vertical projection area, and the change of height does not affect the measurement results. In fact, it is the map plane measurement, which is simple and accurate. 2. The surface method is to actually measure the surface area of the cavity mountain, which should be measured piece by piece, and then summarized to obtain the total area.

This celery base method is more cumbersome, but it can reflect the real use area, and it is more fair for those uses that are mainly planted.

The fifth-order elevation control can also be carried out by the method of photoelectric ranging triangular elevation. 2.The elevation control route should choose the flattest and shortest line connecting each opening, in order to meet the requirements of less stations, fast observation and high accuracy, and no less than 2 leveling points should be buried in each hole to check the position of the two leveling points to be able to place an instrument to jointly measure it is advisable to facilitate the introduction of measurement and avoid the interference of construction.

Solution: From the data in the table, it can be seen that a-c=90, c-d=80, e-d=-60, f-e=50, g-f=-70, b-g=40, +a-d=170, +f-d=-10, +b-f=-30, +b-d=-40, deformed d-b=40, +a-b=210

The height of observation point A is 210 meters relative to observation point B

If e-d is -60m, then d-e is 60mf, if e-e is 50m, then e-f is -50g-f, then f-g is -70, then f-g is 70b-g, if it is 40, then g-b is -40, then a-b=90+80+60+(-50)+70+(-40)=210m

A - C represents the height of the observation point A relative to the observation point C, that is, the point A is higher than the point C, then a - C is 90 meters, i.e. the height of the height of AC = 90.

a-c = 90 and c-d = 80 a-d = 170a-d = 170, e-d = 60 a-e = 230a-e = 230, f-e = 50 a-f = 180a-f = 180, g-f = 70, a-g = 250ag = 250, b-g = 40 ab = 210 a-b phase 210 m.

The relative elevation is to take any point as the reference point plus or minus zero, and you take point a. Point C is 90m positive relative to point A, plus positive plus minus, point C is 90m higher than point A, D-A=175m, B-A=150M.

If e-d is -60m, then d-e is 60mf, and if e-e is 50m, then e-f is -50

If g-f is -70, then f-g is 70

If b-g is 40, then g-b is -40

then a-b=90+80+60+(-50)+70+(-40)=210m

From the data in the table, it can be seen that: a-c=90, c-d=80, d-e=60, e-f=-50, f-g=70, g-b=-40, +: (a-c) + (c-d) + (d-e) + (e-f) + (f-g) + (g-b) = a-b = 90 + 80 + 60-50 + 70-40 = 210

The height of observation point A is 210 meters relative to observation point B

Therefore, a