DE4028214C2 - Method for converting location data generated in values of a geographic coordinate system into a grid form based on a Cartesian coordinate system - Google Patents

Description

The invention relates to a method for converting values into a Coordinate system quasi-continuously generated location data in one on one another coordinate system based form, which represents one on a screen cash card is assigned, a network with data points for the image of the card is defined, each by an intersection of a line of longitude with a Latitude line and are determined by Cartesian coordinate values of the map and using the data points as reference values for the conversion of the in a Koor location data generated in the other coordinate system is used will.

Such a method is known (EP 242 050 A1). In the known method can maps, to which Cartesian coordinate values are assigned, in different scales can be displayed on a screen. From everyone on the screen with Cartesian coordinates is only a reference value for the  Conversion of the Cartesian coordinate values into longitude and latitude values selected. This reference value is the one that lies centrally on the map. The Distances of the points on the map given in Cartesian coordinates from the reference point with a fixed coefficient of longitude and a fixed latitude multiplied.

A vehicle navigation device is also known, with which in an earth-fixed area dinate system despite a scale error of a speed sensor of the vehicle and despite deviations between measured and actual speed Position of the vehicle can be specified with high accuracy. To do this by approaching a terrain point assigned to a unique position Correction quantities calculated (DE 30 33 279 C2).

Geographic information systems allow users to spatially large amounts collect, manage and analyze distributed data. Characteristic here is that this data is indexed spatially or area wise, whereby data from Maps and position data, for example, can be combined and displayed can. So z. B. the locations of moving vehicles, aircraft or ships are displayed on a map displayed on a screen.

The location data of the moving objects, which are communicated to a computer, must be converted into the coordinates of the saved maps.  

Two methods are used for the storage, analysis and output of spatial data:
In the vector representation, data is organized by objects. They are represented by polygons. Geographic objects are represented by points, lines or areas (polygons). For example, cities are represented by points, roads and rivers by lines and lakes, and political units by regions. A vector system can be selected if the data are to be interpreted according to properties. With a vector graphic, a precise representation of the locations on a map is possible; however, this creation of vector maps is time-consuming and requires complex, non-standardized technical facilities.

In the raster display, data is organized according to spatial addresses and with Helped by a grid. The X-Y position of a data field corresponds to that spatial location of the respective feature point. In the elements of the data field are contain the attributes of the respective point. The grid format is suitable for the Processing of characteristics related to areas. The raster graphic comes with Standard facilities and requires less effort than that Vector graphic. The accuracy of the raster graphics is due to deviations of the used map material and due to the use of a constant Calibration factor unsatisfactory in many cases.

For the display of geographic data, especially of locations on a Map graphics that appear on a screen would be beneficial as sources to be able to use card material for the human card reader and nevertheless represent the locations with high precision. Maps of the The type described above is available inexpensively and can e.g. B. manually be scanned.

The invention is therefore based on the object of a method of the beginning to further develop the described genus in such a way that it is simple Location data related to a geographic coordinate system into one Grid form based on a Cartesian coordinate system with great accuracy can be implemented or alternatively the existing ones in grid form  Location data in terms of the geographic coordinate system with large Accuracy can be implemented.

The object is achieved by the features specified in the characterizing part of claim 1.

The invention is based on the principle in concrete Cartesian Coordinate values available raster maps a vectorized network consisting of Longitude and latitude lines to overlap. It will be the respective Crossing points of this network with assignment to the corresponding measure longitude and latitude. This results in one of position-dependent calibration matrix or a calibration network with areas equivalent, location-dependent calibration factors. For the conversion of the coordinates from the geographic to the Cartesian coordinate system and vice versa, depending on the geographical location, the applicable and on the equivalence range limited calibration factor used. So it becomes the point of the Calibration matrix used for the determination of calibration factors, the Longitude and latitude information of a reported location is closest.

Instead of just one point in the calibration network, several, the specified one, can also be used Location data adjacent points of the calibration network, e.g. B. two of four corner points the area in which the latitude and longitude data are located for the calibration to be chosen. The two corner points lie on the same diagonal through the Area. With the selection of these points of the calibration network the accuracy can  influenced and z. B. brought to a desired value.

The data points for calibration are based on the geographical Location data of a point selected so that it is checked whether in the calibration network Data points with larger and smaller coordinate values, only larger or only coordinate values smaller than those of the point exist. Are bigger and there are smaller or only smaller coordinate values of data points the data point with the next smaller coordinate values for the calibration selected. If there are only data points with larger coordinate values, the Data point with the next largest coordinate values for calibration selected. For data points with larger and smaller coordinate values Another data point selected for calibration, whose abscissa value is larger and its ordinate value is smaller than the abscissa or ordinate value of the Point is. These process steps are applied both when Coordinate values of a point in geographic location data as well as in Grid dimensions are available, with the implementation in the other coordinate system to be carried out. The calibration factors result from two data points as the ratio of the difference between the coordinate values of the data points in grid dimension as a counter value and from the difference of the coordinate values of the data points in the geographic coordinate system as nominal if geographic location data should be converted into values for the grid shape.

In the opposite case, d. H. when converting coordinate values of the points The calibration factors correspond to the grid size in geographic location data the reciprocal values of the quotients given above.

The exact coordinate values for the individual points result for the Raster coordinate system from the sum of the coordinate values of the one data point in the grid coordinate dimension and the product of the respective calibration factor with the Difference of the coordinate value in the geographic coordinate system and the Coordinate value of the point in the geographic coordinate system. Geographical Coordinate values result from the sum of the one data point in the geographic coordinate system and the product of each mentioned above  Reciprocal with the difference between the coordinate value of the one data point and the respective point, whereby both coordinate values are used in the raster wet.

After calibration, they are converted into the grid size of the map Location data is shown on the map displayed on a screen. Ongoing changing location data, particularly from a moving object generated, give an accurate display of the variable on the screen Object positions.

It is also possible to select objects from the map whose data are in X-Y Grid dimensions are saved. After that, they will be closest to the selected positions upcoming latitude and longitude information. With the help of the assigned Calibration factors are used to create the location data in latitude and longitude and Z. B. output as control data to a movable object.

For the movable objects whose location data are to be displayed or which receive tax data from a card, it can be vehicles. For The image of the map is defined by data points, each one by one The intersection of the latitude and longitude lines specified on the map is determined and contains the corresponding information about the latitude and longitude.

In addition, each data point has position information in the abscissa and Ordinate axis of the Cartesian coordinate system assigned to that of the rasterized Graphics are based. For example, the length and latitude of one Moving object incoming location data are using the data points the rasterized graphic compared to at least one nearest data point to find. Its location data specified in grid size become the Conversion to the X-Y grid dimension used before the converted data be displayed on a screen or monitor.

Further details, advantages and features of the invention are not only apparent from the claims, the features to be extracted from them - for themselves and / or in Combination, - but also from the preferred one of the drawing Embodiment.

Show it

Fig. 1 shows an arrangement for generating, transmitting and displaying location data in the scheme and

Fig. 2 shows a section of a map shown on a screen with displayed location data of a vehicle.

A vehicle ( 1 ) has a location determining device known per se, which generates location data with reference to the longitude and latitude positions. This location data is transmitted by radio to a fixed station ( 2 ) which receives location data via an antenna ( 3 ), which is followed by a converter ( 4 ) which outputs the location data to an interface ( 5 ). A data processing device ( 6 ), to which a keyboard ( 7 ) and a monitor ( 8 ) are connected, is connected to the interface ( 5 ). A memory (not shown in more detail) is present in the data processing device ( 6 ) and contains a map in raster representation. In the raster display, the elements of a data field are assigned XY coordinate values corresponding to the spatial locations on the map. The elements of the data field contain attributes for the respective map point. The data field structure of the grid is particularly suitable for data representation in programming languages. Information is taken from the digital image data.

The digitally stored map is displayed on the monitor ( 8 ). Only a part of the map can also be displayed, the parts to be displayed being selected using the keyboard ( 7 ).

Fig. 2 shows a section of a map displayed on the monitor (8) (9). The section according to Fig. 2 includes roads (10), (11), (12) having a junction (13) and a branch (14). In the detail of the map ( 9 ), the location of the vehicle ( 1 ) should be shown with high accuracy. High accuracy also means that the vehicle, e.g. B. is displayed precisely on streets, squares, courtyards, etc. on the map using a CURSOR. In Fig. 2 the vehicle ( 1 ) is represented by a point ( 15 ) on the map ( 9 ).

The location data generated by the vehicle is quasi-continuous data. Therefore, the location data provided by the vehicle ( 1 ) must be converted into the rasterized graphic of the map ( 9 ) before it can be displayed on the monitor ( 8 ).

The stored data of the map ( 9 ) are by z. B. manual scanning of a commercially available map. In this way, the map material to be displayed can be created inexpensively. In commercially available maps, e.g. B. the map ( 9 ), longitude lines ( 16 ), ( 17 ), ( 18 ) and latitude lines ( 19 ), ( 20 ), ( 21 ) are given. This information is also contained in the rasterized data field in XY coordinates. This fact is used to display the location data of the vehicle ( 1 ) in latitude and longitude on the map with great precision. This precise representation can be achieved in a simple manner.

A calibration network of data points is defined for the image of the map ( 9 ). Each data point is the intersection of a longitude line and a latitude line contained in the grid of the map. For the section shown in FIG. 2, there are nine data points ( 22 ), ( 23 ), ( 24 ), ( 25 ), ( 26 ), ( 27 ), ( 28 ), ( 29 ) and ( 30 ) as intersection points of the Longitude lines ( 16 ) to ( 18 ) and latitude lines ( 19 ) to ( 21 ). The data points ( 22 ) to ( 30 ) are each assigned ordinate and abscissa values of the Cartesian coordinate system. These ordinate and abscissa values are used to generate calibration factors with which the location data of the vehicle ( 1 ) in the form of length and latitude information are converted by the data processing device ( 6 ) into the XY coordinate values of the raster graphics of the map ( 9 ), before they are displayed on the monitor ( 8 ). A vectorized network consisting of geographical longitude and latitude lines is therefore superimposed on the raster map in concrete Cartesian coordinate values. The intersection points of the longitude and latitude line network are measured in the Cartesian coordinate system, whereby an assignment is obtained that results in a location-dependent calibration network or a calibration matrix with areas of equivalent location-dependent calibration factors.

The incoming location data in the form of the longitude and latitude are first compared with the values of the longitude and latitude lines in order to determine the data point that is the closest to the incoming location data. On the basis of the difference between the longitude and latitude value of the incoming location data and the determined nearest data point, calibration factors are obtained using the XY coordinate values of the data point, with which the longitude and latitude value are multiplied. This results in a representation of the incoming location data in the saved raster format of the map graphic. In this format, the incoming location data is displayed on the map ( 9 ), the point ( 15 ) resulting for a specific position on the street ( 11 ). If a particularly rapid conversion of the location data of the grid size of the longitude and latitude information into the grid size of the XY coordinates is necessary, a data processing device ( 6 ) with parallel and pipeline processing can be used. Depending on the geographical location, the valid calibration factor, which is limited to the equivalence range, is used.

It is also possible to convert location data from the map graphic into location data with latitude and longitude information. This implementation is based on the same network of data points. The XY coordinate values of e.g. B. on the keyboard ( 7 ) selected location of the map ( 9 ) are compared with the XY coordinate values of the data points to determine the closest data point. Calibration factors are obtained from the difference between the location coordinate values and the data point coordinate values with the aid of the longitude and latitude values assigned to the data point, with which the XY location data are converted into those with latitude and longitude information, which are then transmitted by the data processing device ( 6 ) via the antenna ( 3 ) sent out and z. B. received by the vehicle ( 1 ) as target values to be approached.

Instead of just one data point, more, in particular two out of four, of the network including the location can be used for calibration. These the two data points are preferably located diagonally opposite one another. From the  stored latitude and longitude information or the X-Y coordinate data won the calibration factors. Not only can errors when rasterizing the Map reduced, but also systematic errors, e.g. B. the scale, eliminated will.

A point ( 15 ) has as geographical location data the values X _PG , Y _PG , which are based on a geographical Cartesian coordinate system, e.g. B. refer to longitude and latitude. The grid coordinate values that are required for the display on the monitor ( 8 ) in the grid coordinate system are X _PR and Y _PR .

The values X _PR and Y _PR are obtained in the following way:
In a first method step, the closest data points are determined on the basis of the geographic abscissa value X _PG and the geographic ordinate value Y _PG . First, in the context of a comparison operation, the data point is sought whose abscissa value is larger in the geographic coordinate system and whose ordinate value is smaller in the geographic coordinate system than the abscissa X _PG and the ordinate Y _PG z. B. the point ( 15 ). The larger abscissa of the data point in the geographic coordinate system is designated X _1G and the smaller ordinate of the data point is designated Y _1G .

In FIG. 2, determined in the first process step data point of the data point (26) would be.

The next data point required for calibration is determined on the basis of the data point ( 26 ). For this purpose, the ratio of the geographical point ( 15 ) to the calibration network value is determined. A geographic point can be below, within or above the calibration network. A point lies in the abscissa direction below the network if there is no data point in the network whose abscissa value is smaller than the abscissa value of the geographical point. The point lies within the network if there are data points with larger and smaller abscissa values. The data point is above the calibration unit if there are only data points with larger abscissa values. The same applies to the ordinate value of the point. This check is carried out for the respective geographical point. If the geographical point is within or below the calibration network, the data point in the immediately preceding row or column is determined as the second data point. If the geographical point lies above the network, then the data point in the immediately following row or column of the calibration network is selected as the second data point.

The point ( 15 ) lies within the calibration network. Therefore, the longitude line ( 16 ) and the latitude line ( 20 ) of the calibration network are determined in the comparison operation, whereby the data point ( 23 ) is selected as the calibration point. The data point ( 23 ) has the geographical abscissa X _0G and the ordinate Y _0G . The raster abscissa values and the raster coordinate values of the data points ( 23 ), ( 26 ) are predetermined. The raster _{abscissa values of} the data points ( 23 ), ( 26 ) are designated X _0R and X _1R , and the _{raster coordinate values of} the data points ( 23 ), ( 26 ) are designated Y _0R and Y _0R .

With the geographical abscissa and ordinate values and the raster abscissa and raster coordinate values of the data points ( 23 ), ( 26 ), two calibration factors are determined according to the following relationship for the respective coordinate axis:

The coordinate values required for the display in raster form z. B. the point ( 15 ) result from the sum of the coordinate values of the one calibration point and the product of the calibration factor and the difference of the geographic coordinate values of the two data points.

The following equations apply:

X _PR = X _0R + k _x (X _0G - X _PG ) and Y _PR = Y _0R + k _y (Y _0G - Y _PG )

The point, e.g. B. ( 15 ), whose grid coordinate values are X _PR and Y _PR , is displayed on the monitor ( 8 ) with great accuracy.

If grid coordinate values are to be converted into geographic coordinate values, then the abscissa value X _PR and the ordinate value Y _{PR of} a point are used. Similar to the method for determining data points for the calibration described above for geographic coordinates, data points with the abscissa _values X _0R and X _1R and the ordinate values Y _0R and Y _{1R are} determined. Geographical coordinate _values X _0G , X _1G in the abscissa _direction and coordinate _values Y _0G , Y _1G in the ordinate _{direction are} assigned to these data points.

The calibration factors in the two coordinate directions are derived from this determined the following relationships:

The calibration factors for the conversion into geographic location data are therefore the reciprocal values of the calibration factors for the conversion of geographic location data in grid coordinate data. The geographical Coordinate values in the two coordinate directions result from the following Relationships:

The process steps described above cause that within the Calibration network the coordinate values of not on row or column lines lying points are interpolated. The coordinate values from outside the Points lying in the calibration network are extrapolated. For extrapolation two data points are also used, which are the location acts closest to you. The implementation then takes place in a corresponding manner Way, as set out above.  

With the method explained above, inaccuracies in the representation reduced. The method is based on the assumption that the calibration factors within each rectangle delimited by data or calibration points are right everywhere. The smaller these rectangles are, the more this assumption is made to.

The determination of the coordinate values of a in grid coordinates or point to be represented geographical coordinates was above by means of two Data points described. However, the method can also use more than two data or calibration points are carried out.

The data processing device ( 6 ) is provided with raster graphics equipment (also called pixel graphics). This equipment contains a graphics card, the monitor ( 8 ) and a pointer instrument, e.g. B. a mouse. The process is carried out with the display logic of the raster graphics and is independent of a certain type. The data processing device ( 6 ), the keyboard ( 7 ) and the monitor ( 8 ) can be a personal computer of the type PC AT with Matrox PC-1281 graphics card and a mouse of the type Genius GM-6.

Claims (7)

1. A method for converting location data generated almost continuously in values of a coordinate system into a form based on another coordinate system, which is assigned to a map that can be displayed on a screen, a network with data points being defined for the image of the map, each by an intersection of a line of longitude with a line of latitude and are determined by Cartesian coordinate values of the map, and wherein the data points are used as reference values for converting the location data generated in one coordinate system into the other coordinate system, characterized in that for the conversion of and latitude data generated coordinate values (X _PG , Y _PG ) of a geographic coordinate system in Cartesian coordinate values of a raster representation of the map for the respective point is checked whether data points with larger and smaller coordinate values, only larger or there are only smaller coordinate values than those of the point, so that in the presence of larger and smaller or only smaller coordinate values, at least the data point with the next smaller and with only larger coordinate values the data point with the next larger coordinate values is selected as the data point for determining location-dependent calibration factors, that with larger and smaller coordinate values of the data points, at least that data point for the determination of location data-dependent calibration factors is selected, whose abscissa value is larger and whose ordinate value is smaller than the abscissa value or the ordinate value of the point, so that the point specified in the latitude and longitude data is also included the calibration factors are converted into the grid form based on the Cartesian coordinate system, that for the implementation one in each case in the Cartesian coordinate system of the grid form predetermined point, it is checked whether there are larger and smaller coordinate values, only larger or only smaller coordinate values than those of the point in the data point, that in the presence of larger and smaller or only smaller coordinate values, at least the data point with the next smaller coordinate values and only larger coordinates value the data point with the next largest coordinate values is selected as a data point for the determination of location data-dependent calibration factors, that with larger and smaller coordinate values the data point is further selected at least that data point for the determination of location data dependent calibration factors, whose abscissa value is larger and its ordinate value is smaller than the abscissa value or Is the ordinate value of the point, and that the point specified in Cartesian coordinate values with the calibration factors into the coordinate system with length and B riding degree information is converted. 2. The method according to claim 1, characterized, that the calibration factors are obtained from the data of two data points be on the diagonal of an area containing four data points where the location data is. 3. The method according to claim 1 or 2, characterized, that the location data converted into the grid of the map in one displayed on a screen. 4. The method according to any one of the preceding claims, characterized in that in the case of two data points selected for the calibration, the calibration factors are determined for the representation in the Cartesian coordinate system of the raster shape according to the following relationships: where with k _x and k _y the calibration factors in the individual coordinate directions, with X _1G and Y _1G the coordinate _values in the geographic coordinate system of the first data point, with X _0G and Y _0G the coordinate _values in the geographic coordinate system of the second data point, with X _1R , Y _{1R are} the coordinate _values in the grid dimension of the first data point and X _0R , Y _{0R are} the coordinate _{values of} the second data point in the grid dimension. 5. The method according to any one of the preceding claims, characterized in that the coordinate values for a point to be displayed in the Cartesian coordinate system of the raster _shape are determined according to the following relationships: X _PR = X _0R + k _x (X _0G - X _PG ) and Y _PR = Y _0R + k _y (Y _0G - Y _PG ), wherein X _PR and Y _{PR are} the coordinate _values in raster form, X _0R and Y _{0R are} the coordinate _{values of} the one data point in raster form and k _x and k _{y are} the calibration _factors . 6. The method according to any one of the preceding claims, characterized in that at two data points selected for the calibration, the calibration factors for the correction of coordinate values in a Cartesian, geographic coordinate system are determined according to the following relationship: where with k _x and k _y the calibration factors in the individual coordinate directions, with X _1G and Y _1G the coordinate _values in the geographic coordinate system of the first data point, with X _0G and Y _0G the coordinate _values in the geographic coordinate system of the second data point, with X _1R and Y _{1R denotes} the coordinate _values in the grid dimension of the first data point and X _0R and Y _0R the coordinate _values in the grid dimension of the second data point. 7. The method according to claim 1 or 2, characterized in that the coordinate values for a point to be determined in the geographic coordinate system are determined according to the following relationships: where X _PG and Y _{PG denote} the geographic coordinate _values , X _0G and Y _0G the geographic coordinate _{values of} the one data point and k _x and k _y the calibration _factors .