JP4081455B2 - Coordinate conversion method - Google Patents

Description

  The present invention relates to a coordinate conversion method, and more particularly to a coordinate conversion method from Japanese geodetic system coordinates to world geodetic system coordinates.

  A method described in Non-Patent Document 1 is known as a method for converting a survey result of a reference point created based on the Japanese geodetic system into a result based on the world geodetic system. In this conventional example, coordinate conversion is performed by (1) a method using a coordinate conversion program called TKY2JGD, and (2) a reference point result based on the world geodetic system as a known point, and an average with respect to the observed value at the time of setting the reference point The calculation (revision) method, (3) the method based on the re-measurement (revision) of the existing reference point, and (4) the method using the conversion parameter suitable for each region are shown.

  Of these methods, the method (1) is convenient because the coordinate value after conversion can be automatically obtained by applying a predetermined parameter to the old result value. It may not be appropriate to apply to boundary points managed by public organizations. In other words, the 3rd and 4th class reference points, which have a large number, are often performed under conditions where the measurement time and instruments are different, so the difference in error distribution based on the difference in measurement time and the accuracy based on the difference in instruments. Due to the difference, it is not suitable for uniform conversion. In addition, since the boundary point results are derived by performing various calculations such as intersection calculation, there is a problem that the distance and area between boundary points change due to uniform conversion. there is a possibility.

  On the other hand, the method (2) is a conversion method having a relatively wide application range. However, since the average calculation requires angle data at the time of measurement, the conversion to the point where these data do not remain is the most. In addition to the time-consuming re-measurement of (3), as described above at the boundary points, etc., since translation, intersection calculation, etc. are performed in addition to the error distribution by the average network, There are similar circumstances.

  The method (4) is a method recommended for the conversion of the third and fourth class reference points when the coordinate conversion of the first and second class reference points is performed by the methods (2) and (3). The conversion value of the target point is obtained by interpolation based on the conversion value at the conversion value known point in the predetermined range, but the direction of the conversion amount vector in the area including the conversion target point is the same as the premise of interpolation. There must be a trend. In order to satisfy this condition, it is necessary to suitably determine the area to be interpolated with reference to, for example, an average diagram at the time of installation of a reference point, and there is a problem that specialized knowledge is required.

Furthermore, as a common problem in all these cases, if regional crustal deformation has occurred, it must be re-measured. There is also a problem that a range that requires measurement cannot be assumed.
“Public Survey Result Coordinate Conversion Manual with Geodetic Result 2000 Introduction”, [online], Geographical Survey Institute, Ministry of Land, Infrastructure, Transport and Tourism, [April 6, 2004 search], Internet <URL: http: //psgsv.gsi.go .jp / koukyou / henkan_manual / pdf / henkan_manual_p7-p11.pdf>

The present invention has been made to solve the above-described drawbacks, and an object of the present invention is to provide a coordinate conversion method and a coordinate conversion apparatus having high versatility and high conversion accuracy .

According to the present invention, the object is
The coordinate value (old result value) based on the Japanese geodetic system given to the conversion target point in the predetermined area by the computer having the isoline generating means 4, the area dividing means 5, the area searching means 6, and the coordinate calculating means 7 To a coordinate value that conforms to the world geodetic system,
The isolines generating means 4, when the converted value to the World Geodetic System according appropriate method against the old result value of a suitable number of reference points in said area is given, with the converted value and the old result value For each X, Y component difference value, each of the X component difference value and the Y component difference value is set as an elevation value in the X, Y coordinate system, or the difference value of the X, Y2 component amount is set as one component amount on the X, Y plane. A step of generating an isoline 1 with the conversion amount converted as
The area dividing means 5 creating a conversion table 2 in which a difference value is associated with an area divided by the isoline 1 ;
Step S2-1 in which the area search means 6 searches for an area to which the conversion target point belongs in the conversion table 2 .
The coordinate calculation means 7 is achieved by providing a coordinate conversion method for executing step S2-2 to perform coordinate conversion by increasing / decreasing the X and Y difference values corresponding to the area to the old result value of the conversion target point. The

  When converting to the world geodetic coordinate system, first, a conversion table 2 is prepared. The conversion table 2 is created based on the distribution state of the movement amount (difference) by coordinate conversion at the reference point in the area. The selection of the reference point is that (1) the measurement accuracy is high, and (2) it is possible to secure a sufficient number of parameters that are statistically necessary for statistical analysis of the entire region. It is performed as a condition, and preferably, when it is difficult to secure a reference point of the first or second grade or a parameter, an appropriate number of third grade reference points is added to them.

  Therefore, the “region” in the present invention refers to a region having an area or the like that can secure a reference point that satisfies the above two selection conditions, and does not necessarily need to coincide with an administrative division. This refers to an area that is about the size and size of a prefecture.

  After selecting the reference point, coordinate conversion is performed on each reference point. Since the present invention can be roughly evaluated with respect to the selected conversion method by using the output from the contour line output means 8 described later or the coordinate conversion evaluation map B in combination, there are various coordinate conversion methods. Although one can be used, it is desirable to adopt one of the methods described in the above-mentioned “Public Survey Result Coordinate Conversion Manual Accompanying the Introduction of Geodetic Result 2000”. In particular, when the TKY2JGD conversion program is used, the conversion work can be automatically performed, and relatively high accuracy can be expected by the calculation.

  The conversion table 2 calculates the difference between the old result value and the conversion result with respect to the selection reference point in the X and Y directions, and further, an isoline 1 connecting points having the same difference value generated based on the difference. Is generated by assigning the difference value of the contour line 1 in the region divided by.

  The coordinate conversion of the conversion target point using the conversion table 2 generated as described above can be obtained simply by increasing or decreasing the difference value assigned to the region to which the conversion target point belongs to the old result value. As a result, the conversion work is easy, and, as described above, there is no observation data such as the angle and distance of the conversion target point. The same processing as is possible.

  As will be described later, the conversion table 2 is divided into regions by the difference isolines 1, and the isolines 1 serving as boundary lines between the regions can be easily displayed. The display result is obtained by displaying the distribution of the shift amount (difference) by the execution of the predetermined coordinate conversion method in the predetermined area using the contour lines. If there is no crustal movement and the old result value is appropriate, the amount of deviation due to coordinate transformation is considered to have a constant value or a certain tendency. On the other hand, when the contour line 1 is dense, there is a large amount of deviation due to conversion between two adjacent points, and it is possible to estimate the presence of some abnormality with respect to crustal movements or survey results. In addition, as described above, when the conversion target point is a boundary point, and the change in the distance between the boundary points is excessive, the conversion value cannot be adopted, so that it is considered as a target for revision or calculation. .

The above method
Coordinate transformation that converts the coordinates of the conversion point specified on the map database 3 of the predetermined area where the position data is given by the coordinate value (old result value) compliant with the Japanese geodetic system to the coordinate value compliant with the world geodetic system A device,
X, Y for each of the X and Y component difference values between the converted value and the old result value when given a conversion value to the world geodetic system by an appropriate method with respect to an appropriate number of reference points selected from the map database 3 In the Y coordinate system, each of the X component difference value and the Y component difference value is used as an elevation value, or a conversion amount obtained by converting the difference value of the X, Y2 component amount as one component amount on the X, Y plane is used as an elevation value. An isoline generating means 4 for generating an isoline 1;
Area dividing means 5 for dividing the map information plane into areas by the isoline 1 and assigning a difference value corresponding to each divided area;
An area search means 6 for searching the belonging area of the conversion target point based on the old result value;
Coordinate calculation means 7 for increasing / decreasing the assigned difference value of the area to which it belongs to the old result value of the conversion target point and outputting it as a coordinate value after conversion,
It can implement | achieve using the coordinate transformation apparatus which has these.

In this device,
When an isoline outputting means 8 for displaying the isoline 1 generated based on the difference value between the converted value for the reference point and the old result value on the map information is added,
Since it is possible to visually check the difference within the area, that is, the distribution of the movement amount, as described above, the target area for the revision, the revision, etc. can be easily identified, and the intensive about these areas Examination becomes possible.

  According to the present invention, versatility and conversion accuracy can be improved during coordinate conversion.

  As shown in FIG. 1, the coordinate conversion apparatus A includes an input unit 10, an output port 11, and a storage unit 12, and the storage unit 12 stores an area map database 3 including a conversion target point. The map database 3 holds the ID of a reference point and the like existing in the map space, the point type, and the old result value in the plane rectangular coordinate system, and can be displayed two-dimensionally on a display device or the like connected to the output port 11.

  In addition, the coordinate conversion apparatus A includes a conversion table generation unit 9 and a coordinate conversion unit 13. The conversion table generation unit 9 and the coordinate conversion unit 13 can be realized by a program that causes a computer to function as a unit that constitutes each of the above units. In this case, the program is stored in a ROM (not shown) or the program is stored. It is read from the described medium into a memory outside the figure, and a predetermined operation is performed under the control of the CPU outside the figure.

  The conversion table generation unit 9 calculates the difference between the converted coordinate value for the reference point input from the input unit 10 in the isoline generation unit 4 and the old result value at the same point on the map database 3, An isoline 1 is generated from the distribution of the obtained differences, and thereafter, the region dividing means 5 divides the map space using the isoline 1 as a boundary, and the value of the isoline 1 is divided into each divided region. Is assigned as a conversion parameter.

On the other hand, the coordinate conversion unit 13 searches the affiliation area in the conversion table 2 of the given conversion target point, and calculates the post-conversion coordinates using the conversion parameter assigned to the area.
The coordinate conversion includes a generation process (S1) of the conversion table 2 using the conversion table generation unit 9 and a conversion process (S2) using the conversion table 2. In the conversion table generation process (S1), first, Coordinate conversion using the TKY2JGD program is performed on an appropriate number of reference points (step S1-1). The conversion result obtained in step S1-1 is input from the input unit 10 and stored in the storage unit 12. For the reference points selected in the execution of step (S1-1), the first and second reference points are preferentially used, and when the number of parameters is small, a part or all of the third reference points are used. The

  When the post-conversion coordinate values for the reference points are given, first, the isoline generating means 4 searches the storage unit 12 for the reference points that are subject to coordinate conversion (step S1-2), and further, for these reference points. The difference between the old result value and the converted coordinate value is calculated (step S1-3). The difference calculation is performed separately for the X and Y components of the plane rectangular coordinate system, and the calculation results are stored in the storage unit 12 as an X, Y, ΔX table, and an X, Y, ΔY table.

  Thereafter, an isoline 1 is generated for the X, Y, ΔX table or the X, Y, ΔY table (step S1-4). For example, a known contour generation algorithm can be applied to the generation of the isoline 1 in the X, Y, ΔX table by treating ΔX as an elevation value in the X, Y coordinate system. In general, in the contour generation algorithm, the contour line interval is given as an initial setting coefficient. Therefore, by adjusting this via the isoline interval setting unit 14, the contour line 1 output from the isoline generation unit 4 is adjusted. The default value such as 1 (mm) is used when no designation is made.

  In this embodiment, the coordinate conversion apparatus A includes an isoline output means 8. The contour line output means 8 includes a drawing engine (not shown) for converting the contour line 1 into a graphic form and outputting it from a display device connected to the output port 11 or an output device such as a printer. The evaluation map B is drawn. At the time of drawing, the isoline output means 8 calculates the interval between the isolines 1 and 1 based on a preset threshold value, and if there is a place with an interval smaller than the threshold value, the inner area is color-coded. Is done. FIG. 3 is a diagram showing the state of the isoline of the entire region, and FIG. 4 is a part of this, in which the internal region is color-coded because the interval of the isoline 1 at the point P1 is less than or equal to the threshold value. Indicates.

  In this embodiment, the colors are classified into two types, colorless and colored areas, but the type of color coding (number of colors) is determined in consideration of ease of viewing. The threshold value is preferably based on an empirical value obtained from use in another area, but the coordinate conversion evaluation map B shows a guideline for the recalculation and revising area, so it is not necessarily accurate. There is no need to be, and it is sufficient if the changing portion of the congestion level of the contour line 1 can be easily identified.

  In addition, the extraction of the color-coded boundary based on the threshold value is performed by the contour generation algorithm, for example, by interpolating the interpolated values from the vertex coordinates on each side of the Delaunay triangle with the selection reference point as the vertex, and connecting the opposite sides as a contour. If it is, it can be easily performed from the number of generated connections or the interval. Furthermore, the color-coded region need not be the entire region, and can be performed only in the region centered on the coordinate conversion target point. In this case, the interval between the isolines 1 that sandwich the coordinate conversion target point is set as a threshold value. A simple method as compared with can be adopted.

In the above description, the coordinate conversion evaluation map B is created for both ΔX and ΔY. However, the coordinate conversion evaluation map B senses the movement amount during coordinate conversion of the entire region. Since (X, Y, (ΔX ² + ΔY ² ) ^1/2 ) space is assumed, (ΔX ² + ΔY ² ) ^{1 /} on the X, Y plane is assumed. ^An isoline 1 based on the amount of conversion into a quantity that can be displayed with the two component quantities ΔX and ΔY as two component quantities such as 2 may be used.

The coordinate conversion evaluation map B created as described above shows the distribution of the coordinate movement amount after coordinate conversion. For example, the map B can be directly displayed in a color-coded region or at a position straddling it. If there are boundary points PA and PB in Fig. 4,
L = (n−1) d
(Where n is the number of isolines between points, d is the interval between isolines)
It can be immediately seen that a dimensional difference of. This dimensional difference is considered to indicate a change in length (including an area change in the case of 3 points or more) due to boundary point conversion in an unfavorable region. For example, this value is allowed as an error range. By determining whether or not to be performed, it is possible to determine whether or not the coordinate conversion in the region can be performed based on a realistic request.

  In general, by knowing the tendency of the contour line 1 in the region, for example, in a region where the contour lines 1 are dense and swirled, the crustal movement or the average behind Since problems such as inappropriateness of the network and accuracy of the reference point during surveying can be assumed, it can be used as a basis for re-measurement, recalculation, or as a basis for considering re-measurement.

  When the isoline 1 is generated as described above, the region dividing means 5 performs region division in the X and Y planes (step S1-5). The area dividing unit 5 polygonizes each area having the isoline 1 as a boundary, adds ΔX or ΔY as an internal attribute of the polygon, and outputs the converted table 2 to the storage unit 12 (step S1). -6). Although the conversion table 2 depends on the production of a coordinate conversion unit 13 to be described later, basically, it is sufficient if ΔX and ΔY have a data structure in which ΔX and ΔY have a one-to-one correspondence with the area number (ID).

  When the conversion table generation step (S1) is completed as described above, the coordinate conversion step (S2) by the coordinate conversion unit 13 having the area search means 6 and the coordinate calculation means 7 is performed. In this embodiment, an area number in the map database 3 or an area division diagram such as an isoline diagram overlaid on the map database 3 is linked to an area number in the conversion table 2, and the area division map is used for coordinate conversion. After searching for the conversion target point, the ID of the conversion table 2 is searched to obtain ΔX and ΔY of the point finding.

  The search of the affiliation area of the coordinate conversion target point can be directly known, for example, when the coordinate conversion target point is designated on the display device on which the area division diagram is displayed. In the case of collective input, etc., a search is performed for polygons that include the conversion target coordinate point in the area (step S2-1).

When the area search in the area search means 6 is completed, coordinate conversion in the coordinate calculation means 7 is performed (step S2-2). Coordinate transformation is (Xo, Yo) when the old result value read from the map database 3 is
(Xo + ΔX, Yo + ΔY), which is output from an output device connected to the output port 11 by appropriate means.

  In the above description, the reference point coordinate conversion (step S1-1) is performed using the TKY2JGD program. However, the calculation is performed for comparatively higher reference points up to about the third grade. Therefore, the revised value can be used as the converted value.

It is a functional block diagram which shows this invention. It is a figure which shows the flowchart of a coordinate transformation method. It is a figure which shows the output from an isoline production | generation means, (a) is an isoline diagram by (DELTA) X, (b) shows the isoline diagram by (DELTA) Y. The partial enlarged view of the map for coordinate transformation evaluation is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Isoline 2 Conversion table 3 Map database 4 Isoline generation means 5 Area division means 6 Area search means 7 Coordinate calculation means 8 Isoline output means A Coordinate conversion apparatus B Coordinate conversion evaluation map

Claims (5)

A computer having isoline generation means, area segmentation means, area search means, and coordinate calculation means uses the world geodetic system to obtain coordinate values (old result values) conforming to the Japanese geodetic system given to the conversion target points in a predetermined area. A coordinate value that conforms to
X of the isolines generating means, when the converted value to the World Geodetic System according appropriate method against the old result value of a suitable number of reference points in said area is given, with the converted value and the old result value For each of the Y and Y component difference values, each of the X component difference value and the Y component difference value in the X and Y coordinate system is set as an altitude value, or the difference value of the X and Y component amounts on the X and Y plane is set as one component amount. A step of generating an isoline using the converted conversion amount as an elevation value ,
The area dividing means creating a conversion table in which a difference value is associated with an area divided by the isoline;
The area search means searching the area to which the conversion target point belongs in the conversion table ;
Said coordinate calculating means, coordinate transformation method for executing a step of respectively increasing or decreasing coordinate conversion X corresponding to the area, the Y difference value to the old result value of the conversion target point.   The coordinate conversion method according to claim 1, wherein the conversion to the world geodetic system is obtained by a TKY2JGD conversion program.   The coordinate transformation according to claim 1, wherein the transformation to the world geodetic system is obtained by performing an average calculation with respect to other reference points using a reference point for which accuracy of matching with the world geodetic system is guaranteed as a known point. Method. A coordinate conversion device that converts the coordinates of the conversion target point specified on the map database of a given area where position data is given by coordinate values (old result values) compliant with the Japanese geodetic system into coordinate values compliant with the world geodetic system Because
X between the converted value and the old result value when the converted value to the World Geodetic System according suitably process with respect to the reference point of the number of suitable selected from the said map database is given, X for each Y component difference values, Y In the coordinate system, each of the X component difference value and the Y component difference value is used as the elevation value, or the conversion amount obtained by converting the difference value of the X, Y2 component amount on the X, Y plane as one component amount is used as the elevation value. Isoline generating means for generating value lines;
Area dividing means for dividing the map information plane into areas by the isolines and assigning a difference value corresponding to each divided area;
An area search means for searching an area to which the conversion target point belongs based on an old result value;
Coordinate calculation means for increasing / decreasing the assigned difference value of the area to which it belongs to the old result value of the conversion target point and outputting it as a coordinate value after conversion,
A coordinate transformation device.   5. The coordinate transformation apparatus according to claim 4, further comprising isoline output means for displaying an isoline generated based on a difference value between the transformation value for the reference point and the old result value on map information.

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