What is elevation 5 and what does elevation mean?

Elevation refers to the distance from a point along the plumb line to the absolute base plane, which is called absolute elevation. Abbreviated as elevation. The distance from a point along the plumb line to a hypothetical horizontal base is called the hypothetical elevation.

"Elevation" is a surveying and mapping word, and in popular understanding, elevation is actually altitude. In surveying, elevation is defined as the height of a point on the Earth's surface in the direction of the Earth's gravity, that is, the height of the Earth's gravitational line at the center of gravity. As a result, the direction of the elevation of each point on the earth's surface is different.

Elevation is a feature that determines the location of ground points. The methods of elevation measurement include leveling and triangulation, and leveling is the main method for precise elevation determination. Leveling is a method of estimating the elevation by measuring the difference in height between ground points using an instrument (level) that provides a horizontal line of sight.

There are two main types of elevation systems used in countries around the world: orthometric systems and normal elevation systems, and their corresponding elevation names are altitude and approximate altitude respectively, which are collectively referred to as elevation. There is a difference between a normal height system and a positive height system, mainly due to the different effects of the gravity field, and the gravity line will produce some offset.

The elevation system used in China is a normal height system. If it is not for scientific research, just for general use, the normal high system results in the country can also be called altitude.

In the past, China used the average sea surface of the Yellow Sea obtained from the observation results of the Qingdao tide gauge station from 1950 to 1956 as the zero point of elevation, which was called the "1956 Yellow Sea elevation system". After re-examination, it was found that the elevation was too short and inaccurate, so it was recalculated by using the observation data of Qingdao tide gauge station from 1950 to 1979 and named it "National Elevation Benchmark in 1985". The national leveling point is located in Guanxiang Mountain, Qingdao City, which is the basis for elevation measurement in China.

Its elevation is calculated based on the "1985 National Elevation Benchmark" as the average sea surface of zero, and the original "1956 Yellow Sea Elevation System" is abolished.

The attached picture shows Mount Everest, which was re-measured by China in 2005, making it the most ambitious elevation measurement in history. The survey took a lot of money and nearly half a year, and the results were announced in September 2005 after the survey: the elevation of Mount Everest is meters.

On October 9, the State Bureau of Surveying and Mapping officially announced that the new height of Mount Everest is meters. The rice that has been used for many years at the front will no longer be used in the future.

There are two main methods of altimetry of Mount Everest: the first method is the traditional classical measurement method, which is based on the triangular elevation measurement method, combined with leveling, triangulation, traverse measurement, etc., to correct and calculate the data obtained in gravity, atmosphere and other aspects, and finally obtain the effective data of Mount Everest elevation. The second method is GPS satellite geodesy, which first establishes a reference ellipsoid that can fit the shape of the earth to the greatest extent, and obtains the accurate three-dimensional coordinates of Mount Everest relative to this earth reference ellipsoid through the satellite GPS instrument, and then, as long as we determine the elevation difference between the reference ellipsoid and the real earth at the highest point of Mount Everest, we can get the accurate elevation of Mount Everest.

The altitude of an object to be measured is often referred to as altitude by using a specified sea level as the zero elevation.

Elevations are divided into: absolute and relative elevations.

China stipulates that the average sea surface of the Yellow Sea is used as the datum of elevation (absolute plus or minus), and the origin of the level is set up in Qingdao as the starting point of the national elevation. The vertical distance that a ground point is above the water level is called the "absolute elevation".

Select any level as the datum plane for elevation calculation, and this level is called a hypothetical level. The perpendicular distance between the point on one side of the ground and the assumed water level is called"Relative elevation"

Elevation is a kind of relative elevation, for example, the indoor floor is generally used as a positive and negative point in the construction of houses, and the relative elevation obtained by this is the elevation Different fields have different requirements

Gaussian plane Cartesian coordinates establishment: in the large area mapping, can not be regarded as the earth's spherical surface as a plane, mapping can use the Gaussian plane Cartesian coordinate system, it is based on the meridian and the equator projection as a straight line perpendicular to each other, the projection of the meridian is the x-axis, the equatorial projection is the y-axis, and its intersection is the coordinate origin.

Plane Cartesian coordinates: When the survey area is small, the plane Cartesian coordinates can be used, with the x-axis as the vertical axis, which generally represents the north-south direction, and the y-axis as the horizontal axis to represent the east-west direction.

Absolute elevation: The distance from the ground point to the geoid in the direction of the perpendicular line is called the absolute elevation.

Relative elevation: The lead-straight distance from a ground point to any level is called relative elevation.

Through engineering practice, the author finds that the GPS fast static technology can be used to jointly measure the reference station and leveling point, and the GPS elevation can be estimated by the linear fitting adjustment of the EGM96 model, so as to make a reasonable evaluation of the engineering achievements of the external commission. (It doesn't seem to have anything to do with network technology, what are you used for!) )

"Building elevation" is a term that is rarely used, and the most commonly used term is "building elevation".

Elevation generally refers to the elevation point that is unified across the country. The origin of elevation, there is an elevation measurement observatory in Qingdao in China, which uses the average sea surface height of the Yellow Sea measured over the years as the starting point for calculation. For example, if the elevation point of a certain place is, it means that this point is higher than the elevation datum point of Qingdao.

This elevation is called the "absolute elevation" of the point.

The height of Mount Everest is the absolute elevation.

The elevation system datum starting point is different for each country and cannot be compared.

The difference between two elevations is called relative elevation. For example, the average elevation of the Red Plains is about 3,600 meters. Then the Hongyuan area is about 3068 meters higher than the urban area of Chengdu, so the relative elevation between Hongyuan and Chengdu is 3068 meters.

When designing, the design institute should give the absolute elevation of plus or minus 0 for each unit building. It is generally written as "the absolute elevation of this building". Indicates what is the plus or minus 0 elevation of the building.

Buildings are generally represented by elevation. Generally, it is the ground elevation of the ground floor (floor) of the building. All other elevations are measured from plus or minus zero of the building. For example, the elevation of one floor is meters, the elevation of 10 floors is meters, and so on.

Note: Building levels are not the same as structural levels. In general, the elevation of the structure is about 50 mm higher than the elevation of the building. This is to take into account the screed layer, mortar bonding layer, floor tiles and other factors on top of the floor structure layer.

Note 2: The floor elevation of the corridor, toilet and floor should be lower than the ground elevation of the ordinary room (floor) to prevent water from backflowing.

Note 3: The ground floor of the general building is at least 300 mm higher than the outdoor floor.

1. Elevation refers to the height of a certain empty point relative to the datum, and there are four kinds of elevation systems commonly used at present, including normal height, normal height, force height and geodetic elevation, and the elevation datum has different definitions in various countries. An elevation system is a one-dimensional coordinate system that defines the distance from a point along a specific path to a reference plane.

2. Elevation system refers to the elevation system defined relative to the starting surface of different properties (geoid plane, quasi-geoid plane, ellipsoidal surface, etc.).

3. The elevation system uses different simple datums to represent the height of the ground point, or adopts different processing methods for the leveling data to produce different systems, which are divided into normal height, normal height, force height and earth elevation systems.

<> Elevation Point: This is an information point that is marked with an elevation value, usually with a contour line.

Cooperate with the expression of geomorphological features.

Elevation information. In addition to the differences in individual elevation attributes, on the one hand, the distribution relationship between the distribution of elevation points and the important topographic feature units, rivers, roads and other natural or human elements makes the individual elevation points have different importance significance in geographical properties. On the other hand, the undulations of the regional topography make the elevation point groups show different sparse relationships in the spatial distribution.

I believe that many people often have a small right-angled isosceles triangle on the construction drawing, and the tip of the triangle is upward or downward, which is actually the symbol of the façade. The layman may not understand very well, so Yang. <>

I believe that many people often have a small right-angled isosceles triangle on the construction drawing, and the tip of the triangle is upward or downward, which is actually the symbol of the façade. The layman may not understand it very well, so what does the elevation angle mean? How is the elevation calculated?

Let's take a look with Bian Xiao.

1.What does altitude mean?

Elevation refers to the height of each part of the building, which is the vertical height of a part of the building relative to the datum (elevation zero point), and is the basis for vertical positioning. To further understand the meaning of elevations, we need to know the types of elevations. There are two types of elevations: absolute elevation and relative elevation, which vary according to the choice of datum.

Absolute elevation: refers to the elevation with the datum plane uniformly specified by the country or region as the zero point. China stipulates that the mean sea level of the Yellow Sea near Qingdao is zero above sea level; The calculated elevation is called the absolute elevation.

The outdoor floor elevation in the general plan of the construction drawing often adopts the absolute elevation. In addition to the general plan, relative elevations are generally used. Relative elevation, that is, the absolute elevation of the main ground on the first floor of the building is set to the zero point of the relative elevation, which is represented by ".

The above level is a positive level, and the lower level is a negative level. The positive elevation is not preceded by the number, and the negative elevation is preceded by the number.

Let's take a look at the façade label, which is a right-angled isosceles triangle, where the façade symbol for the outdoor terrace in the master plan is represented by a blackened right-angled isosceles triangle. The top of the symbol refers to the height position to be labeled. The tip is usually down or up.

The elevation number is written to the left or right of the elevation symbol. The elevation number is in meters (m) and is written to the third decimal place (the second decimal place is destined in general floor plans). To better understand what altitude means and how to read, here is an example.

The relationship between relative and absolute elevation is often explained in general design instructions, for example.

For example, the ground elevation of the first floor key excitation room is equivalent to the absolute elevation. This makes it possible to measure the indoor ground elevation of the ground floor of a building based on the local leveling point (absolute elevation).

2. How to calculate the elevation?

Elevation: Take a reference point as 0 point, and the elevation difference between other places in China and this reference point is the elevation of the Yellow Sea and the elevation of Wusongkou, that is, a cornerstone here is 0 meters, and the elevation of other places is subject to this. Elevation measurement is simple:

After the instrument is leveled, its line of sight is horizontal, and when the level is standing at point A, the horizontal line in the instrument is aligned with a point of the level, then this point will have a reading H1, and then the measurement is calculated: the elevation of point A H1-H2 = the elevation of point B.

This section describes the meaning of elevation and how to calculate it. I'm sure everyone should know by now. In fact, knowing the elevation is only one of the knowledge points of architectural drawings. Later, I will explain more about the architectural drawings similar to the façade to help you understand the building.

Leveling is used.

The formula for calculating the elevation is: Foresight Rounded Point Elevation = Rear Sight Point Elevation + Rear View Reading - Front View Reading.

Total station. It is usually displayed directly in the instrument.

Design elevation refers to the elevation required to be achieved at a point in an engineering design. It is the elevation of the pavement extending to the center line of the pavement when the project is finally formed.

The design elevation is a relative elevation, which is the elevation set by the design institute on the design drawings, in order to facilitate construction, most of the ground on the first floor is set to plus or minus 00, so the elevation of other places also has a relative value relative to plus or minus 00. The ground elevation is the absolute elevation, which is relative to the altitude, and the Yellow Sea level is used as the reference plane.

Design Elevation Calculation Method:

From: ground elevation at point A + spacing between a and b slope ratio = ground elevation at point b; Vertical distance h=(a, b spacing) 2r --r is the radius of the vertical curve; Detain: the design elevation of point b = the ground elevation of point b + (-vertical distance h --"+" in the case of concave curve, and "-" in the case of convex curve

The relationship between the design elevation and the tangent elevation:

Design elevation = tangent elevation longitudinal distance. The design elevation is the elevation required to be reached after the completion of the project, and the tangent elevation is the elevation of the starting and ending points of the slope section when calculating the corresponding slope. The relationship between the two is the design elevation = tangent elevation longitudinal distance. <

In local areas, it is sometimes necessary to assume an elevation starting surface, and the vertical distance from the ground point to the level is called the relative elevation.

Absolute elevation, or elevation, is the distance from a point on the ground to the geoid in the direction of the perpendicular.

The plumb distance from a ground point to a geoid is called the absolute elevation of that point.