A coordinate conversion method and device in geographic information data

Abstract

The present application discloses a coordinate conversion method and device in geographic information data, the method comprising: establishing a coordinate conversion model, wherein the coordinate conversion model is used to convert between at least two coordinate systems: a local plane coordinate system, a geodetic coordinate system, and a spatial rectangular coordinate system; obtaining a data file in the File GeoDatabase format; traversing and screening the elements in the data file to obtain all target elements in the data to be converted; topologically checking and repairing the data to be converted, and inputting the checked and repaired elements to be converted into the coordinate conversion model to obtain the element results after the coordinates are converted; after all the elements to be converted are converted, generating a converted File GeoDatabase file. The present application solves the problem of low efficiency in converting coordinates in the FileGDB file of ARCGIS, thereby improving the efficiency of file coordinate conversion.

Description

Technical Field

[0001] The present application relates to the field of geographic information processing, and in particular, to a coordinate conversion method and device in geographic information data. Background Art

[0002] At present, with the continuous development of geographic information technology, ArcGIS has become an indispensable software in the geographic information industry. More and more enterprises, companies, research institutions, institutions, etc. use ArcGIS to process geographic data. Due to the needs of engineering construction, urban planning and scientific research, surveying and mapping surveys must be carried out, resulting in a large amount of geographic information data. These data are massive, and ArcGIS is usually used for data storage processing. In addition, since large cities and major national engineering projects can establish independent plane coordinate systems, the coordinate systems of many data are not unified. Considering the need to establish a comprehensive and unified geodetic coordinate system, it is currently necessary to unify the coordinates when data is stored, so there is a problem of coordinate conversion.

[0003] These data are basically processed using the geographic information system software ArcGIS and stored in the file format of the geospatial database file (File Geodatabase, referred to as FileGDB). Efficiency, accuracy and ease of operation are particularly important for coordinate conversion of these massive GDB files. The traditional method is to use ArcGIS Engine or ArcGIS Object for secondary development and coordinate processing of FileGDB files, but this does not meet user requirements in terms of conversion efficiency and ease of operation, especially for large-scale data, which takes a huge amount of time to convert.

[0004] Using ArcGIS Object for secondary development and coordinate conversion of File GeoDatabase requires the installation of ArcGIS components and ArcObject authorization to access File GeoDatabase. At the same time, the conversion efficiency for data of more than tens of GB is still insufficient, which takes a very long time and limits the convenience of software deployment. Summary of the invention

[0005] The embodiments of the present application provide a method and device for converting coordinates in geographic information data, so as to at least solve the problem of low efficiency in converting coordinates in a FileGDB file of ARCGIS.

[0006] According to one aspect of the present application, a coordinate conversion method in geographic information data is provided, comprising: establishing a coordinate conversion model, wherein the coordinate conversion model is used to convert between at least two of the following coordinate systems: a local plane coordinate system, a geodetic coordinate system, and a spatial rectangular coordinate system; obtaining a data file in a File GeoDatabase format; traversing and screening the elements in the data file to obtain all target elements in the data to be subjected to coordinate conversion; performing a topological check and repair on the data to be converted, and inputting the checked and repaired elements to be subjected to coordinate conversion into the coordinate conversion model to obtain element results after coordinate conversion; after all elements to be subjected to coordinate conversion are converted, generating a converted File GeoDatabase file, wherein the converted file includes the correct coordinates after conversion.

[0007] Furthermore, traversing and screening all elements in the data file to obtain all target elements in the data to be transformed in coordinates includes: judging and retrieving whether there are data types in the data that are not supported by the FileGeoDatabase interface itself during traversal; and traversing all elements in the supported data to obtain all target elements in the data to be transformed in coordinates.

[0008] Furthermore, the method further includes: if there is unsupported data, information of the unsupported data is returned and marked, and the unsupported data is screened out when generating a result file.

[0009] Furthermore, the result of the element after the coordinate conversion is input into the coordinate conversion model includes: judging whether the element needs to be reconstructed according to the geometric attributes of the element to be converted; if reconstruction is required, the element is input into the coordinate conversion model after reconstruction; if reconstruction is not required, the element is directly input into the coordinate conversion model; a good memory optimization mechanism and data management measures are used to prevent errors in data conversion midway, and multi-threading is enabled to accelerate coordinate calculation.

[0010] Furthermore, elements whose geometric attributes are Bezier curves need to be reconstructed.

[0011] According to another aspect of the present application, a coordinate conversion device in geographic information data is also provided, including: a coordinate conversion model module, used to establish a coordinate conversion model, wherein the coordinate conversion model is used to convert between at least two of the following coordinates: a local plane coordinate system, a geodetic coordinate system, and a spatial rectangular coordinate system; a data interpretation module, which obtains a data file in the File GeoDatabase format; a data extraction module, which traverses and filters the elements in the data file to obtain all target elements in the data to be coordinate converted; a data processing module, which performs topological inspection and repair on the data to be converted, and inputs the checked and repaired elements to be coordinate converted into the coordinate conversion model to obtain the element results after the coordinates are converted; an output module, which generates a converted File GeoDatabase file after all the elements to be coordinate converted are converted, wherein the converted file includes the correct coordinates after the conversion.

[0012] Furthermore, the data extraction module is used to: determine and retrieve whether there is a data type in the data that is not supported by the File GeoDatabase interface itself during traversal; traverse all elements in the data that can be supported to obtain all target elements in the data to be coordinate converted.

[0013] Furthermore, the data extraction module is also used to: if there is unsupported data, return the information of the unsupported data and mark it, and filter out the unsupported data when generating the result file.

[0014] Furthermore, the data processing module is used to determine whether the element needs to be reconstructed based on the geometric attributes of the element to be transformed; if reconstruction is required, it is input into the coordinate transformation model after reconstruction; if reconstruction is not required, it is directly input into the coordinate transformation model.

[0015] Furthermore, elements whose geometric attributes are Bezier curves need to be reconstructed.

[0016] In the embodiment of the present application, a coordinate conversion model is established, wherein the coordinate conversion model is used to convert between at least two coordinate systems as follows: a local plane coordinate system, a geodetic coordinate system, and a spatial rectangular coordinate system; a data file in the File GeoDatabase format is obtained; the elements in the data file are traversed and screened to obtain all target elements in the data to be converted; a topological check and repair are performed on the data to be converted, and the checked and repaired elements to be converted are input into the coordinate conversion model to obtain the element results after the coordinates are converted; after all elements to be converted are converted, a converted FileGeoDatabase file is generated, wherein the converted file includes the correct coordinates after the conversion. The present application solves the problem of low efficiency in converting coordinates in the FileGDB file of ARCGIS, thereby improving the efficiency of file coordinate conversion. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0018] Figure 1 is a flowchart of a coordinate conversion method in geographic information data according to an embodiment of the present application;

[0019] Figure 2 This is a flowchart of File Geodatabase file coordinate conversion according to an embodiment of the present application. DETAILED DESCRIPTION

[0020] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0021] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0022] In this embodiment, a coordinate conversion method in geographic information data is provided. Figure 1 is a flowchart of a coordinate conversion method in geographic information data according to an embodiment of the present application. Figure 1 As shown, the method comprises the following steps:

[0023] Step S102, establishing a coordinate conversion model, wherein the coordinate conversion model is used to convert between at least two of the following coordinates: a local plane coordinate system, a geodetic coordinate system, and a spatial rectangular coordinate system;

[0024] Step S104, obtaining data in FileGDB format;

[0025] For example, based on GDAL, the File GeoDatabase API provided by ESRI is jointly compiled to obtain the data interface of FileGDB, so as to interpret the data in FileGDB format, obtain the information of each layer and target element, and obtain the data in FileGDB format through the API provided by ArcGIS software, including all layers and various elements such as points, lines, surfaces, multi-points, multi-lines, multi-surfaces, and polyhedra in the layers; traverse and filter the elements in the data to obtain all the target elements in the data to be converted into coordinates;

[0026] Step S106, traversing and screening all elements in the data file to obtain all target elements in the data to be subjected to coordinate transformation;

[0027] In this step, it is optional to determine whether there is unsupported data in the data, and if there is unsupported data, return information about the unsupported data; traverse all elements in the data that can be supported to obtain all elements in the data that need to be transformed; and automatically perform topological check and repair on the data to be transformed. Determine whether the elements need to be reconstructed based on the geometric attributes of the elements to be transformed, and if reconstruction is required, input them into the coordinate transformation model after reconstruction; if reconstruction is not required, directly input them into the coordinate transformation model.

[0028] Step S108, performing topological check and repair on the data to be converted, and inputting the checked and repaired elements to be converted into the coordinate conversion model to obtain the element results after the coordinate conversion;

[0029] In this step, the data to be converted can be topologically checked and repaired, and then it can be determined whether the elements need to be reconstructed based on the geometric properties of the elements to be converted. If reconstruction is required, it is input into the coordinate conversion model after reconstruction; if reconstruction is not required, it is directly input into the coordinate conversion model.

[0030] In this step, multi-threading can be used to process massive amounts of data. This way, good memory optimization mechanisms and data management measures can be used to prevent data conversion errors midway, and multi-threading can be used to accelerate coordinate calculations and improve coordinate conversion efficiency.

[0031] In this step, the topology check is used to check the topological structure between the data, and when an error occurs in the topological structure between the data, the erroneous topological structure is repaired.

[0032] Step S110, after all elements to be transformed are transformed, a transformed file is generated and output, wherein the transformed file includes the correct transformed coordinates. For example, an element whose geometric attribute is a Bezier curve needs to be reconstructed.

[0033] The above steps solve the problem of low efficiency in converting coordinates in ARCGIS FileGDB files, thereby improving the efficiency of file coordinate conversion.

[0034] In the above steps, there are many ways to convert between the plane coordinate system, the geodetic coordinate system and the spatial rectangular coordinate system, which are explained below with examples.

[0035] Example 1

[0036] MATLAB can be used to write 8 MATLAB sub-functions to calculate and realize the mutual conversion between coordinate systems. The 8 MATLAB sub-functions are defval, deg2dms, dms2deg, ellipsoidpara, arc_length, coordtransfer, gauss_bl2xy, and gauss_xy2bl, respectively. The defval function is used to set the default value of the function variable, the deg2dm and dms2deg functions are used to realize the mutual conversion between different angle formats, the ellipsoidpara function is used to calculate the parameters and auxiliary functions of different ellipsoids, the arc_length function is used to calculate the arc length of the meridian and the parallel circle, the coordtransfer function is used to realize the mutual conversion between the geodetic coordinates and the spatial rectangular coordinates, and the gauss_bl2xy function and the gauss_xy2bl function realize the forward and reverse calculation of the Gaussian plane coordinates. 1000 sets of randomly generated geodetic coordinate data (L, B, H) are converted into spatial rectangular coordinates (X, Y, Z), and then the generated spatial rectangular coordinate data are used to inversely calculate the geodetic coordinate data, and the difference between the inversely calculated geodetic coordinates and the original coordinates is calculated, and the respective root mean squares are calculated from the difference as the accuracy evaluation index, and 1000 sets of geodetic coordinate data (L, B) are used to calculate the Gaussian plane coordinates (x, y) and the corresponding central meridian longitude and belt number, and then the Gaussian plane coordinates (x, y) are used for inverse calculation to obtain new geodetic coordinates, and the corresponding root mean square is calculated. The mutual conversion between the geodetic coordinates and the spatial rectangular coordinates is that the geodetic coordinates of any point P in the earth space are the geodetic latitude B, the geodetic longitude L and the geodetic height H.

[0037] Example 2

[0038] The plane coordinate system is converted into a spatial rectangular coordinate system, and the geodetic coordinate system is also converted into a spatial rectangular coordinate system. The connection between the two in the spatial rectangular coordinate system is established through the seven-parameter transformation method in the spatial rectangular coordinate system. A path for arbitrary conversion between plane coordinates and geodetic coordinates can be established to realize the conversion of plane coordinates to geodetic coordinates.

[0039] There are three other coordinate transformation methods that can play the same role, which will not be described here.

[0040] In an optional implementation, multiple coordinate transformation models may be obtained, for example, the above example 1 and example 2 are each a coordinate transformation model. A set of coordinates is transformed using multiple coordinate transformation models, and then a model with the shortest transformation time is obtained, and the model with the shortest transformation time is used as the coordinate transformation model used in the above step S102.

[0041] The following is an explanation in conjunction with an embodiment. This embodiment provides a FileGDB file coordinate conversion technology based on the Geospatial Data Abstraction Library (GDAL for short). This embodiment provides a method for converting the coordinates of a FileGDB file by programming after integrating and compiling the File Geodatabase API with GDAL, realizing the coordinate conversion technology route of the FileGDB file out of ArcGIS, and completing the development of the coordinate conversion software FileGDB file conversion module. This ensures that the software deployment does not require ArcGIS components, while ensuring the high precision of the conversion calculation. Compared with other FileGDB coordinate conversion methods, it also improves the efficiency of FileGDB file coordinate conversion.

[0042] GDAL stands for Geospatial Data Abstraction Library, which is an open source library for reading and writing spatial data (including raster data and vector data) under the X / MIT license. It uses abstract data models to express the various file formats it supports, and also uses a series of command line tools to convert and process data. OGR (OGR Simple Features Libraru) is a branch of the GDAL project. Its functions are similar to GDAL, except that it provides support for reading and writing vector data. At the same time, it implements a class for processing spatial reference information, which is used to process the control information of spatial data. OGR provides support for reading and writing vector data formats, including ESRI Shapefiles, S-57, SDTS, PostGIS, Oracle Spatial and other formats.

[0043] All classes in OGR are mainly composed of the following seven parts, including Geometry geometric objects, SpatialReference spatial references, Feature features, Feature Class Definition feature class definitions, Layer layers, Data Source data sources, and Drivers drivers.

[0044] First, a coordinate conversion model is established to enable coordinates to be converted between different plane coordinate systems, geodetic coordinate systems, and spatial rectangular coordinate systems, and written as a calling function, so that the coordinate points in the geometric attributes of different data in the parsed FileGDB can be used for coordinate conversion calculations between different coordinate systems. The next step is to parse the data of FileGDB. Based on the components compiled by GDAL through the File GeoDatabase API provided by ESRI, FileGDB data can be read. After opening the GDB data, the feature dataset is first determined to determine which feature tables are in the GDB file and which tables FileGDB API does not support editing. Then the data of the feature table is read, and while traversing the feature table information, the geometric attributes of the information in the feature table are determined to be arcs. If it is not an arc, then the API is directly used to call the established coordinate conversion model to complete the coordinate conversion of the data. If it is an arc, the arc data is marked so that it can be processed using GDAL, the arc is reconstructed, and then processed using the FileGDB API, and the coordinate conversion model is called to complete the coordinate conversion. When calling the coordinate transformation model calculation, use good memory optimization mechanisms and data management measures to prevent errors in the conversion of massive data, and accelerate coordinate calculations through multi-threading. If the data set in FileGDB cannot be processed, then the information about the data that the GDB file cannot process is returned and stored in the program running log.

[0045] For the data that has completed the coordinate conversion, ArcGIS is used to verify and compare the data to ensure that the converted data has not lost or changed other information except the spatial geometric attributes. At the same time, the calculation accuracy is verified to check whether the result meets the conversion accuracy.

[0046] Figure 2 This is a flowchart of File Geodatabase file coordinate conversion according to an embodiment of the present application, such as Figure 2As shown, first input GDB data, then determine the dataset and feature table in GDB. If the dataset and data table are not supported, return the information of the supported dataset and data table. If they are supported, call the coordinate conversion model. Traverse the supported datasets, data tables, and feature tables to determine whether the geometric attributes of the elements included therein can be directly converted to coordinates. If so, call the coordinate conversion model for conversion. If not, use GDAL to compile the rent of FileGDB for processing, and then call the coordinate conversion model for coordinate conversion after processing. After all GDB elements are converted, output the converted GDB file.

[0047] In the present embodiment, the FileGDB file conversion program developed using File Geodatabase API and GDAL can be run independently, and ArcGIS components no longer need to be installed. Meanwhile, FileGDB data can have good resolution, and can well improve conversion efficiency. When carrying out large-capacity, long-term File Geodatabase file coordinate conversion, there are good memory optimization mechanisms and data management measures to prevent data conversion from making mistakes midway. The coordinate conversion model established can also have good calculation accuracy, with distance calculation accuracy to 0.001mm and angle calculation accuracy to 0.001 seconds. For commonly used points, lines, faces, multi-points, multi-faceted, polyhedrons, etc., can all be well converted.

[0048] When the surveying and mapping data generated by engineering construction, urban planning and scientific research are stored in the database, it is necessary to unify the coordinates and perform coordinate conversion and update, thus saving human resources and promoting work progress.

[0049] The technical solution proposed in the present embodiment realizes the coordinate conversion technology route of File Geodatabase file separation from ArcGIS, and completes the development of coordinate conversion software. And when ensuring the high precision of conversion calculation, compared with the previous GDB coordinate conversion technology route, the efficiency of GDB file coordinate conversion is also improved. When carrying out large-capacity, long-term File Geodatabase file coordinate conversion, there is a good memory optimization mechanism and data management measures to prevent data conversion from making mistakes midway. The coordinate conversion model established can also have good calculation accuracy, and the distance calculation accuracy is 0.001mm and the angle calculation is accurate to 0.001 second. For commonly used points, lines, faces, multi-points, multi-faceted, polyhedrons, etc., good conversion can be carried out.

[0050] In this embodiment, an electronic device is provided, including a memory and a processor. The memory stores a computer program, and the processor is configured to run the computer program to execute the method in the above embodiment.

[0051] The above program can be run in the processor, or it can be stored in the memory (or computer-readable medium), which includes permanent and non-permanent, removable and non-removable media. Information storage can be achieved by any method or technology. Information can be computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, read-only compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined in this article, computer-readable media does not include temporary computer-readable media (transitory media), such as modulated data signals and carrier waves.

[0052] These computer programs can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps of the functions specified in one or more blocks can be implemented by different modules corresponding to different steps.

[0053] Such a device or system is provided in this embodiment. The device is called a coordinate conversion device in geographic information data, and includes: a coordinate conversion model module, which is used to establish a coordinate conversion model, wherein the coordinate conversion model is used to convert between at least two coordinates: a local plane coordinate system, a geodetic coordinate system, and a spatial rectangular coordinate system; a data interpretation module, which obtains a data file in the File GeoDatabase format; a data extraction module, which traverses and screens the elements in the data file to obtain all target elements to be converted in the data; a data processing module, which performs topological inspection and repair on the data to be converted, and inputs the checked and repaired elements to be converted into the coordinate conversion model to obtain the element results after the coordinates are converted; an output module, which generates a converted File GeoDatabase file after all elements to be converted are converted, wherein the converted file includes the correct coordinates after the conversion.

[0054] The system or device is used to implement the functions of the method in the above-mentioned embodiment. Each module in the system or device corresponds to each step in the method, which has been explained in the method and will not be repeated here.

[0055] For example, the data extraction module is used to: determine and retrieve whether there is a data type in the data that is not supported by the FileGeoDatabase interface itself during traversal; traverse all elements in the data that can be supported to obtain all target elements in the data to be transformed. Optionally, the data extraction module is also used to: if there is unsupported data, return the information of the unsupported data and mark it, and filter out the unsupported data when generating the result file.

[0056] For another example, the data processing module is used to determine whether the element needs to be reconstructed according to the geometric attributes of the element to be transformed, and if reconstruction is required, input it into the coordinate transformation model after reconstruction, and if reconstruction is not required, directly input it into the coordinate transformation model. Optionally, the element whose geometric attribute is a Bezier curve needs to be reconstructed.

[0057] The above-mentioned embodiment solves the problem of low efficiency in converting coordinates in the FileGDB file of ARCGIS, thereby improving the efficiency of file coordinate conversion.

[0058] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims

1. A coordinate conversion method in geographic information data, characterized in that: include: Establishing a coordinate conversion model, wherein the coordinate conversion model is used to convert between at least two of the following coordinate systems: a local plane coordinate system, a geodetic coordinate system, and a spatial rectangular coordinate system; Get the data file in FileGeoDatabase format; Traversing and screening the elements in the data file to obtain all target elements in the data to be subjected to coordinate transformation; Performing topological check and repair on the data to be converted, and inputting the checked and repaired elements to be converted into the coordinate conversion model to obtain the element results after the coordinate conversion; wherein, inputting into the coordinate conversion model to obtain the element results after the coordinate conversion includes: judging whether the elements need to be reconstructed according to the geometric attributes of the elements to be converted, if reconstruction is required, inputting into the coordinate conversion model after reconstruction, if reconstruction is not required, directly inputting into the coordinate conversion model, using good memory optimization mechanisms and data management measures to prevent errors in data conversion midway, and enabling multi-threading to accelerate coordinate calculation; elements whose geometric attributes are Bezier curves need to be reconstructed; After all elements to be subjected to coordinate conversion are converted, a converted File GeoDatabase file is generated, wherein the converted file includes the correct coordinates after conversion.

2. The method according to claim 1, characterized in that Traversing and screening all elements in the data file to obtain all target elements in the data to be transformed into coordinates include: During the traversal, it is determined and retrieved whether there is a data type in the data that is not supported by the FileGeoDatabase interface itself; All elements in the data that can be supported are traversed to obtain all target elements in the data that need to be coordinate transformed.

3. The method according to claim 2, characterized in that Also includes: If there is any unsupported data, the information of the unsupported data is returned and marked, and the unsupported data is filtered out when the result file is generated.

4. A coordinate conversion device in geographic information data, characterized in that: include: A coordinate conversion model module, used to establish a coordinate conversion model, wherein the coordinate conversion model is used to convert between at least two of the following coordinates: a local plane coordinate system, a geodetic coordinate system, and a spatial rectangular coordinate system; Data interpretation module, obtains data files in FileGeoDatabase format; A data extraction module traverses and screens the elements in the data file to obtain all target elements in the data to be subjected to coordinate transformation; The data processing module performs topological inspection and repair on the data to be converted, and inputs the checked and repaired elements to be converted into the coordinate conversion model to obtain the element results after the coordinate conversion; wherein, the element results after the coordinate conversion obtained by inputting into the coordinate conversion model include: judging whether the element needs to be reconstructed according to the geometric attributes of the elements to be converted, if reconstruction is required, inputting into the coordinate conversion model after reconstruction, if reconstruction is not required, directly inputting into the coordinate conversion model, using good memory optimization mechanism and data management measures to prevent errors in data conversion midway, and enabling multi-threading to accelerate coordinate calculation; elements whose geometric attributes are Bezier curves need to be reconstructed; The output module generates a converted FileGeoDatabase file after all elements to be converted have been converted, wherein the converted file includes the correct coordinates after the conversion.

5. The device according to claim 4, characterized in that The data extraction module is used to: During the traversal, it is determined and retrieved whether there is a data type in the data that is not supported by the FileGeoDatabase interface itself; All elements in the data that can be supported are traversed to obtain all target elements in the data that need to be coordinate transformed.

6. The device according to claim 5, characterized in that The data extraction module is also used for: If there is any unsupported data, the information of the unsupported data is returned and marked, and the unsupported data is filtered out when the result file is generated.

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