Measuring device and measuring method

Abstract

To solve the problems in which conventional arts get involved, that is, to provide a surveying-purpose device that uses an external corner or internal corner not only as a surveying reference point, but also as a level reference point (a bench mark), and to provide a surveying method that uses the surveying-purpose device.SOLUTION: A surveying-purpose device according to the present invention comprises: a ruler plate that is made of an L-shaped plate in a plan view; and a supporting cylinder that is installed in a top surface of the ruler plate. The supporting cylinder is arranged almost vertically to the ruler plate. Then, an inner side L-shaped line or an exterior side L-shaped line abuts against an almost vertically intersecting exterior corner or internal corner, and in turn the ruler plate is almost horizontally arranged. In a state with the ruler plate almost horizontally arranged, when inserting a pin of a surveying-purpose reflection prism into an insertion hole, the surveying-purpose reflection prism is arranged almost vertically, and a lower end of the pin abuts against the top surface.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a technology for a device particularly used for indoor surveying, and more specifically, to a surveying device that can be installed at the inside and outside corners and a surveying method using the same.

Background Art

[0002] When constructing buildings such as logistics warehouses and factories, floor level surveying (hereinafter referred to as "floor level measurement") is carried out when the pouring of the floor concrete is completed. Conventionally, when performing this floor level measurement, it has been the mainstream to perform plane coordinate surveying using a center line on the floor surface as a reference line, and to perform level measurement using a leveling mark provided on a column.

[0003] Normally, since the plane coordinates (X, Y) of the apex of a column (i.e., the outside corner) in a plan view are known, a reference line (for example, a relief line at a certain distance from the column) can be set by using a plurality of columns, that is, a plane coordinate system (generally an arbitrary coordinate system) can be set on the floor surface. Further, by setting a plurality of reference lines that intersect in a grid pattern, the plane coordinates of the intersection points of the reference lines can be obtained from various conditions (such as the interval between the reference lines and the relief amount from the column surface). Then, after sighting a point with a known height (i.e., a benchmark) such as a leveling mark with a level (for example, an auto level), the height of the position is measured by sighting a staff placed at the intersection point of the reference lines.

[0004] Conventional floor level surveying was carried out in the following procedure: by setting reference lines, the plane coordinates were determined, and then, using an automatic level, the height was repeatedly measured at each intersection of the reference lines. That is, two steps were required: a step of grasping the plane coordinates and a step of determining the height at that position. Moreover, at least two operators, one responsible for the level and the other for the staff, were needed. Also, in cases where it was necessary to determine the plane coordinates of an arbitrary point that was not an intersection of the reference lines, it was necessary to secure two people: one responsible for surveying instruments such as total stations and transits, and the other for installing a surveying reflecting prism (so-called target) at the measurement point. On the other hand, the results of the floor level survey (i.e., plane coordinates and height) were recorded on-site by the surveyor on drawings or field notebooks. Furthermore, when it was desired to display the survey results on CAD (Computer Aided Design), the operator had to re-enter (so-called manual input) the numerical values recorded on the drawings, etc.

[0005] As described above, conventional floor level surveying had problems such as requiring two steps, being time-consuming and laborious in the work, and needing to secure at least two operators, that is, it cost a considerable amount for the surveying work. Furthermore, the work of the operator recording the survey results and manually inputting them to obtain CAD data was both laborious and prone to errors, and such inconveniences were particularly prominent in cases where the floor area was large.

[0006] By the way, it was usually explained that the plane coordinates of the outside corners of the columns were known. Therefore, if the outside corners of the columns were used as survey reference points, the plane coordinates of any measurement point could be determined, that is, it was liberated from setting reference lines in a grid pattern. Specifically, by installing surveying instruments such as total stations and transits and sighting the outside corners of two columns, the installation coordinates of the surveying instruments could be obtained, and as a result, the coordinates of any measurement point could be determined.

[0007] However, when using the corner of a column as a survey reference point, a survey reflector prism must be placed at that corner in a predetermined orientation (e.g., the pin being vertical). However, the survey reflector prism itself becomes an obstacle and cannot be placed as desired. Note that various techniques using the corner of a column as a survey reference point have been proposed. For example, in Patent Document 1, a surveying device is proposed in which a sight with an acute tip and first and second reflecting prisms are arranged at regular intervals on a straight line.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] According to the technique disclosed in Patent Document 1, it is possible to measure the planar coordinates of the corner of a column or use the corner of a column as a survey reference point. However, since two or more survey reflector prisms are used, the manufacturing cost is high. Moreover, since these survey reflector prisms are permanently installed, it is difficult to perform sighting by automatic tracking. In addition, the surveying device of Patent Document 1 has a problem that it is necessary to maintain a horizontal posture while checking a level, which requires manual labor and the posture becomes unstable, so the survey accuracy is not stable. Furthermore, although planar coordinates can be obtained, the height cannot be grasped, and it is necessary to perform leveling again, so the problems of conventional floor level measurement cannot be solved.

[0010] The problem of the present invention is to solve the problems of the prior art, that is, to provide a surveying device that can be used with the corner or edge as a survey reference point and also as a level reference point (benchmark), and a surveying method using the same.

Means for Solving the Problems

[0011] The invention of the present application focuses on the fact that the horizontal posture of an L-shaped plate material is automatically maintained by arranging it at an external corner or an internal corner, and it is an invention made based on an unprecedented idea.

[0012] The surveying device of the present invention includes a scale plate made of a plate material with an L-shaped plan view, and a support cylinder installed on the upper surface of the scale plate. Inside the scale plate, an inner L-shaped line composed of two substantially vertical (including vertical) line segments is formed, and outside the scale plate, an outer L-shaped line composed of two substantially vertical (including vertical) line segments is formed. The support cylinder is arranged substantially perpendicular (including vertical) to the scale plate, and an insertion hole penetrating the support cylinder is formed inside. When the inner L-shaped line abuts against an external corner intersecting substantially vertically (including vertically), or when the outer L-shaped line abuts against an internal corner intersecting substantially vertically (including vertically), the scale plate is arranged substantially horizontally (including horizontally). In this state, when the pin of the surveying reflecting prism is inserted into the insertion hole, the surveying reflecting prism is arranged substantially vertically (including vertically), and the lower end of the pin abuts against the upper surface of the scale plate.

[0013] The surveying device of the present invention can also be configured such that two or more support cylinders are installed on the upper surface of the scale plate.

[0014] The surveying device of the present invention can also be configured such that a spirit level using a bubble is provided on the upper surface of the scale plate.

[0015] The surveying device of the present invention can also be configured to further include a wall plate. This wall plate is arranged substantially perpendicular (including vertical) to the scale plate and is attached to the inner L-shaped line of the scale plate. In this case, when the inner L-shaped line abuts against a column having an external corner intersecting substantially vertically (including vertically), the wall plate abuts against the wall surface of the column.

[0016] The surveying method of the present invention is a method for obtaining the coordinates of an arbitrary point using the surveying device of the present invention, and includes a first placement step, a first sighting step, a second placement step, a second sighting step, an installation position calculation step, and a coordinate acquisition step. Among these, in the first placement step, the surveying device is placed so as to abut on the first corner where the inner L-shaped line of the surveying device intersects substantially vertically (including vertically), or on the first corner where the outer L-shaped line of the surveying device intersects substantially vertically (including vertically). In the first sighting step, with the scale plate abutting on the first corner (or the first corner), the pin of the surveying reflection prism is inserted into the insertion hole, and the surveying reflection prism is sighted by the surveying instrument. Similarly, in the second placement step, the surveying device is placed so as to abut on the second corner where the inner L-shaped line of the surveying device intersects substantially vertically (including vertically) (or the second corner where the outer L-shaped line of the surveying device intersects substantially vertically (including vertically)), and in the second sighting step, with the scale plate abutting on the second corner (or the second corner), the pin of the surveying reflection prism is inserted into the insertion hole, and the surveying reflection prism is sighted by the surveying instrument. In the installation position calculation step, the coordinates of the installation position of the surveying device are calculated based on the measurement results obtained in the first sighting step and the second sighting step. And in the coordinate acquisition step, the surveying reflection prism is placed at an arbitrary measurement point, and the coordinates of the measurement point are acquired by sighting the surveying reflection prism with the surveying instrument. Note that when the scale plate abuts on the first corner (or the first corner), the center coordinates of the insertion hole are known, and when the scale plate abuts on the second corner (or the second corner), the center coordinates of the insertion hole are known.

Effect of the Invention

[0017] The surveying device and the surveying method of the present invention have the following effects. (1) By one sighting with the surveying instrument, the reference plane coordinates and the reference height can be obtained, and as a result, the floor level survey can be performed more efficiently than in the prior art. (2) By simply abutting the inner L-shaped line or the outer L-shaped line on the corner or the corner, the substantially horizontal (including horizontal) posture of the scale plate is stably maintained, and as a result, the measurement results can be obtained with stable accuracy. (3) By using a measuring instrument, it is not necessary to record the measurement results on-site on drawings or the like, and CAD data can be automatically obtained without manual input. (4) Furthermore, by using an automatic tracking type measuring instrument, even a single operator can perform floor level measurement.

Brief Description of Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0019] Examples of embodiments of the measuring device and the measuring method of the present invention will be described based on the drawings.

[0020] 1. Measuring Device First, the measuring device of the present invention will be described in detail. The measuring method of the present invention is a method mainly for performing measurement indoors using the measuring device of the present invention. Therefore, first, the measuring device of the present invention will be described, and then the measuring method of the present invention will be described.

[0021] Figure 1 is a perspective view schematically showing the surveying device 100 of the present invention. As shown in this figure, the surveying device 100 of the present invention is composed of a scale plate 110 and a support cylinder 120, and can further include a wall plate 130 and a level 140.

[0022] The scale plate 110 has an L-shaped plan view as shown in Fig. 2(a) and is a thin plate-like member as shown in Fig. 2(b). Note that Fig. 2(a) is a plan view of the surveying device 100 seen from above, and Fig. 2(b) is a side view of the surveying device 100 seen from the side. Inside the scale plate 110 (upper left side in the figure), an inner L-shaped line IL composed of two substantially vertical (including vertical) line segments is formed, and outside it (lower right side in the figure), an outer L-shaped line OL composed of two substantially vertical (including vertical) line segments is formed.

[0023] The support cylinder 120 supports the surveying reflecting prism PR as shown in Fig. 3 and is a member including a main body portion 121 (Fig. 1) and an insertion hole 122 (Fig. 1) provided at the central portion thereof. Note that Fig. 3 is a side view schematically showing the surveying device 100 supporting the surveying reflecting prism PR in a state of being in contact with a pillar. This support cylinder 120 is installed on the upper surface of the scale plate 110 so that the insertion hole 122 is substantially perpendicular (including perpendicular) to the scale plate 110. Also, the insertion hole 122 penetrates through the entire length of the main body portion 121. Therefore, when the pin of the surveying reflecting prism PR is inserted into the insertion hole 122, the lower end of the pin will be grounded on the upper surface of the scale plate 110.

[0024] The support cylinder 120 only needs to be installed at one location on the scale plate 110. However, depending on the location where it is arranged, the support cylinder 120 (that is, the surveying reflecting prism PR) may be located at a position where it is difficult to sight from the surveying instrument. Therefore, in order to increase the options for installing the surveying reflecting prism PR, the support cylinder 120 can also be installed at two or more locations on the scale plate 110.

[0025] As shown in FIGS. 1 and 2(b), the wall plate 130 is a plate-like member attached along the inner L-shaped line IL on the lower surface side of the template plate 110 so as to be substantially perpendicular (including perpendicular) to the template plate 110. Note that the wall plate 130 can be attached to the template plate 110 over the entire length of the inner L-shaped line IL (i.e., with an extension equal to the length of the inner L-shaped line IL), or can be partially attached to each of the two line segments forming the inner L-shaped line IL. Also, the wall plate 130 can be fixed to the template plate 110 so as to be non-removable, or the wall plate 130 can be attached to the template plate 110 so as to be removable. Furthermore, the wall plate 130 can be attached along the outer L-shaped line OL instead of (or in addition to) the inner L-shaped line IL.

[0026] As shown in FIG. 4, the measuring device 100 is used by arranging it such that the inner L-shaped line IL of the template plate 110 abuts against the outside corner, or as shown in FIG. 5, by arranging it such that the outer L-shaped line OL of the template plate 110 abuts against the inside corner. For example, as shown in FIG. 3, when the wall plate 130 (i.e., the inner L-shaped line IL) is abutted against the outside corner of a column where two substantially vertical planes (including vertical planes) intersect substantially perpendicularly (including perpendicularly), the template plate 110 becomes substantially horizontal (including horizontal), and the insertion hole 122 of the support cylinder 120 becomes substantially vertical (including vertical). Thereby, the measuring reflecting prism PR with its pin inserted through the insertion hole 122 becomes substantially vertical (including vertical), that is, the measuring reflecting prism PR can indicate the planar position (X, Y) of the lower end of the pin. Also, if the measuring device 100 is arranged such that the upper surface of the template plate 110 becomes a mark (e.g., a mark 1 m high from the floor surface) provided on the column, the measuring reflecting prism PR can indicate the height (Z) of the mark by the lower end of the pin.

[0027] Incidentally, when the wall plate 130 arranged substantially vertically (including vertically) abuts on an outside corner or an inside corner where two substantially vertical wall surfaces (including vertical wall surfaces) intersect substantially vertically (including vertically), the wall plate 130 becomes a substantially vertical plane (including a vertical plane), and the scale plate 110 becomes substantially horizontal (including horizontal). That is, when two movable surfaces that intersect vertically are abutted on two fixed surfaces that intersect vertically, the postures of these movable surfaces are defined by the fixed surfaces. For example, if the fixed surface is vertical, the movable surface also becomes vertical. On the other hand, when two line segments that intersect vertically are abutted on two fixed surfaces that intersect vertically, the postures of these line segments are not defined by the fixed surfaces. That is, just by abutting the inner L-shaped line IL or the outer L-shaped line OL on two fixed surfaces that intersect vertically, the posture of the scale plate 110 is not determined. However, since the scale plate 110 is a plate material, a wall surface (hereinafter referred to as a "thickness surface") is formed in the thickness direction, and usually, this thickness surface and the upper surface or the lower surface of the plate material are substantially vertical (including vertically). Therefore, even if the wall plate 130 is omitted, if the inner L-shaped line IL is arranged to abut on the outside corner (or the outer L-shaped line OL is arranged to abut on the inside corner), the scale plate 110 becomes substantially horizontal (including horizontal), and the insertion hole 122 of the support cylinder 120 becomes substantially vertical (including vertically).

[0028] As described above, if the inner L-shaped line IL is arranged to abut on the outside corner (or the outer L-shaped line OL is arranged to abut on the inside corner), the scale plate 110 becomes substantially horizontal (including horizontal). However, the operator who arranges the surveying device 100 may sometimes want to confirm that the scale plate 110 is substantially horizontal (including horizontal). In this case, as shown in FIGS. 1 and 2, a spirit level 140 using a bubble may be provided on the upper surface of the scale plate 110.

[0029] The support cylinder 120 can support the surveying reflecting prism PR, that is, it is not necessary to secure an operator with the surveying reflecting prism PR, which is suitable for labor saving. On the other hand, by providing the support cylinder 120, the entire surveying device 100 becomes larger, making handling and storage slightly difficult, and the number of parts also increases, resulting in a slightly higher manufacturing cost. Therefore, as shown in FIG. 6, a marker 150 can be installed on the leveling plate 110, and the support cylinder 120 can be omitted. In this case, since the operator needs to set the surveying reflecting prism PR at the position of the marker 150 so that the operator is in a vertical posture, although it is necessary to secure the operator, the surveying device 100 becomes compact and the manufacturing cost can be suppressed. Of course, similar to the support cylinder 120, the marker 150 can be provided at only one location or at two or more locations.

[0030] Hereinafter, an example of using the surveying device 100 will be described with reference to FIG. 7. FIG. 7 is a plan view for explaining an example of performing surveying by arranging the surveying device 100 at the corner of a pillar. Usually, when performing indoor surveying such as floor level surveying, a plane coordinate (usually an arbitrary coordinate system) is set indoors. At this time, as shown in FIG. 7, it is common to set two orthogonal axes (X-axis, Y-axis) along the wall surface constituting the pillar. In addition, the corner of the pillar has a known plane coordinate, that is, it can be used as a plane reference point. Furthermore, the height of the plumb line (for example, a line 1 m high from the floor surface) provided on the pillar is known, that is, it can be used as an elevation reference point (benchmark).

[0031] On one hand, the center point of the insertion hole 122 of the scale plate 110 and the center point of the marker 150 (i.e., the planar position indicated by the surveying reflecting prism PR) are positions based on the corner (connection point of two line segments) of the inner L-shaped line IL or positions based on the corner of the outer L-shaped line OL that are grasped in advance. Therefore, after arranging the scale plate 110 so that the inner L-shaped line IL abuts against the protruding corner (or the outer L-shaped line OL abuts against the recessed corner), when inserting the surveying reflecting prism PR into the insertion hole 122 (or setting it at the marker 150 position), the positional relationship between the planar position of the surveying reflecting prism PR and the planar position of the protruding corner of the column becomes clear. For example, in FIG. 7, the planar coordinates of the protruding corner of the column are (X1, Y1), and since the center point of the insertion hole 122 is separated from the corner of the inner L-shaped line IL by (δX, δY), the planar position indicated by the surveying reflecting prism PR is (X1 - δX, Y1 - δY). Thus, by using the surveying device 100, the position of the surveying reflecting prism PR can be used as a planar reference point, and furthermore, by aligning the scale plate 110 with the ground ink, the height of the surveying reflecting prism PR can be used as a benchmark.

[0032] 2. Surveying method Subsequently, the surveying method of the present invention will be described with reference to FIG. 8. The surveying method of the present invention is a method mainly for indoor surveying using the surveying device 100 described so far. Therefore, descriptions overlapping with those described for the surveying device 100 will be avoided, and only the content specific to the surveying method of the present invention will be described. That is, the content not described here is the same as that described in "1. Surveying device".

[0033] FIG. 8 is a flowchart showing the main steps of the surveying method of the present invention. As shown in this figure, the surveying method of the present invention can be roughly classified into a "preliminary step" and a "measurement step" surrounded by a dashed line. Among these, the preliminary step is a step of determining the position where surveying instruments such as total stations are installed. Hereinafter, the preliminary step will be described in detail.

[0034] First, the operator installs the surveying instrument at a desired position. Then, the operator places the surveying device 100 at the first corner (or the first entrance corner) and inserts the surveying reflecting prism PR into the insertion hole 122 (Step 211). At this time, as described above, the surveying device 100 is arranged so that the inner L-shaped line IL abuts on the corner (or the outer L-shaped line OL abuts on the entrance corner). When the surveying device 100 is placed at the first corner (or the first entrance corner), the surveying reflecting prism PR is sighted by the surveying instrument (Step 212). Note that the survey can be carried out by two operators, one who sights the surveying instrument and the other who maintains the surveying device 100 in place, or it can be carried out by one operator using an automatically tracking surveying instrument. The same operator installs the surveying device 100 and then sequentially places the surveying device 100, that is, performs the surveying work alone.

[0035] When sighting the surveying reflecting prism PR set at the first corner (or the first entrance corner), the operator places the surveying device 100 at the second corner (or the second entrance corner) and inserts the surveying reflecting prism PR into the insertion hole 122 (Step 213). Then, when the surveying device 100 is placed at the second corner (or the second entrance corner), the surveying reflecting prism PR is sighted by the surveying instrument (Step 214). The angle (azimuth) and distance between the installation position of the surveying instrument and the first corner (or the first entrance corner) are obtained by the first sighting step (Step 212). Similarly, the angle (azimuth) and distance between the installation position of the surveying instrument and the second corner (or the second entrance corner) are obtained by the second sighting step (Step 214). Thereby, the installation position of the surveying instrument can be calculated (Step 215). Also, at either (or both) of the first corner (or the first entrance corner) and the second corner (or the second entrance corner), if the surveying device 100 is placed after aligning the upper surface of the scale plate 110 with the column's ink line, the installation height of the surveying instrument can also be grasped.

[0036] After the above preparatory process is completed, the measurement process is subsequently carried out. Specifically, after an operator installs a surveying reflection prism PR at a desired measurement point, a surveying instrument sights the surveying reflection prism PR (Step221). At this time, the operator installs the surveying reflection prism PR as usual without using the surveying device 100. Then, using the result of the surveying instrument sighting the surveying reflection prism PR, the planar coordinates and height of the measurement point are calculated (Step222). By repeating this arbitrary point sighting process (Step221), the planar coordinates and height of a plurality of measurement points can be obtained.

Industrial Applicability

[0037] The surveying device and surveying method of the present invention can be used for surveying various buildings (especially indoor surveying) with corners such as logistics warehouses and factories. Also, in addition to floor level surveying, it can be used when surveying the planar position and height of various facilities.

Explanation of Reference Numerals

[0038] 100 Surveying device of the present invention 110 Scale plate (of the surveying device) 120 Support cylinder (of the surveying device) 121 Main body part (of the support cylinder) 122 Insertion hole (of the support cylinder) 130 Wall plate (of the surveying device) 140 Level (of the surveying device) 150 Marker (of the surveying device) IL Inner L-shaped line (of the surveying device) OL Outer L-shaped line (of the surveying device) PR Surveying reflection prism

Claims

1. A scale plate made of a plate material having an L-shaped view in plan, and a support cylinder installed on the upper surface of the scale plate, characterized in that inside the scale plate, an inner L-shaped line composed of two perpendicular or substantially perpendicular line segments is formed, and outside the scale plate, an outer L-shaped line composed of two perpendicular or substantially perpendicular line segments is formed; the support cylinder is arranged perpendicular or substantially perpendicular to the scale plate, and an insertion hole penetrating the support cylinder is formed inside; when the inner L-shaped line abuts on the outermost corner where two perpendicular or substantially perpendicular lines cross, or the outer L-shaped line abuts on the innermost corner where two perpendicular or substantially perpendicular lines cross, the scale plate is arranged horizontally or substantially horizontally; when, with the scale plate arranged horizontally or substantially horizontally, the pin of the surveying reflecting prism is inserted into the insertion hole, the surveying reflecting prism is arranged vertically or substantially vertically, and the lower end of the pin of the surveying reflecting prism abuts on the upper surface of the scale plate. A surveying device characterized by the above.

2. Two or more of the support cylinders are installed on the upper surface of the scale plate. The surveying device according to Claim 1, characterized by the above.

3. A spirit level using a bubble is provided on the upper surface of the scale plate. The surveying device according to Claim 1 or Claim 2, characterized by the above.

4. Further provided with a wall plate arranged perpendicular or substantially perpendicular to the scale plate and attached to the inner L-shaped line of the scale plate, when the inner L-shaped line abuts on a column having an outermost corner where two perpendicular or substantially perpendicular lines cross, the wall plate abuts on the wall surface of the column. The surveying device according to any one of Claims 1 to 3, characterized by the above.

5. A method for obtaining the coordinates of an arbitrary point using the surveying device according to any one of Claims 1 to 4, comprising: a first arranging step of arranging the surveying device so that the inner L-shaped line of the surveying device abuts on the first outermost corner where two perpendicular or substantially perpendicular lines cross, or the outer L-shaped line of the surveying device abuts on the first innermost corner where two perpendicular or substantially perpendicular lines cross; a first sighting step of inserting the pin of the surveying reflecting prism into the insertion hole while the scale plate abuts on the first outermost corner or the first innermost corner, and sighting the surveying reflecting prism with surveying equipment. A second placement step of placing the measuring device so as to abut against a second exit corner that intersects the inner L-shaped line of the measuring device vertically or substantially vertically, or a second entrance corner that intersects the outer L-shaped line of the measuring device vertically or substantially vertically; A second aiming step of inserting the pin of the measuring reflection prism into the insertion hole while the scale plate is in contact with the second exit corner or the second entrance corner, and aiming at the measuring reflection prism with the measuring instrument; An installation position calculation step of calculating the coordinates of the installation position of the measuring device based on the measurement result obtained in the first aiming step and the measurement result obtained in the second aiming step; A coordinate acquisition step of arranging the measuring reflection prism at an arbitrary measurement point and acquiring the coordinates of the measurement point by aiming at the measuring reflection prism with the measuring instrument; When the scale plate abuts against the first exit corner or the first entrance corner, the center coordinates of the insertion hole are known, and when the scale plate abuts against the second exit corner or the second entrance corner, the center coordinates of the insertion hole are known. A surveying method characterized by the above.

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