Table of contents
2. Detailed explanation of GP model
[Tilted warehousing-Generate S3M]
1. Introduction to skew data
Oblique photography refers to images obtained by an aerial camera with a certain tilt angle. Oblique photography technology is a high-tech technology developed in the field of international surveying, mapping and remote sensing in recent years. It overturns the previous limitation that orthophotos can only be taken from vertical angles. By mounting multiple sensors on the same flying platform and collecting images from five different angles, including vertical and four tilts, more complete information about ground objects can be obtained.
Aerial oblique images can not only truly reflect the surface conditions, but also greatly expand the application fields of remote sensing images by using advanced positioning technology to embed precise geographical information, richer image information, and more advanced user experience. This technology can be widely used in emergency command, homeland security, urban management, real estate taxation and other fields.
The original tilt data can be output as osgb, obj, fbx, stl, etc. Raw tilt data in osgb format is commonly used in SuperMap iDesktopX for processing. If the tilt data is obj, it can also be converted to osgb through tools before processing.
This article mainly introduces the use of SuperMap iDesktopX to build a processing automation model and realize one-click osgb tilt storage into S3MB.
2. Detailed explanation of GP model
Among the common functions, the tilt storage function includes basic settings and advanced settings for rebuilding LOD, coordinate transformation, modifying the center point, and generating normals.
Since iDesktop The operators used include [Oblique warehousing - Texture compression], [Oblique warehousing - Rebuild top layer], [Oblique warehousing - Cropping], [Generate configuration file], [Oblique warehousing - Generate S3M], [Oblique photography import]. MongoDB] etc.
The operators provided in the software [Toolbox] for tilt data processing are not only the ones mentioned above. You can open the operators in [3D Data] - [Oblique Data Processing] to connect the required operator functions by yourself to build an automated model that meets business needs.
This article uses [Generate Configuration File] and [Tilted Storage-Generate S3M] to achieve a basic tilted storage. Other operators can achieve tilt optimization, which will not be mentioned in this article.
[Generate configuration file]
Usually the original tilt data is output as a large number of osgb files, and the supporting metadata.xml meta file is also output to record important information such as the coordinate system of the original tilt data and the position of the insertion point. The [Generate Configuration File] function is to generate a configuration file in *.scp format from oblique photography data. 3D slice cache files in *.scp format can be loaded directly in the scene to realize batch loading and browsing of 3D slice cache data. You can also directly use the configuration file in *.scp format for operations such as optimization, singleization, and warehousing in subsequent optimization. Generating the configuration file does not change the original data. The original data format is not in osgb format. The configuration file is only an index file for convenience.
The method of using the GPA operator is the same as the [Generate Configuration File] in the normal function. You need to enter [source data] as required information, and optionally fill in the metadata file, target data name and path, anchor point XYZ, and source coordinate system. *Note that when the optional parameters are not filled in, the default data coordinate system is a plane non-projected coordinate system, and the insertion point position is (0, 0, 0). It is recommended to input the metadata.xml file information according to the original data to avoid impact Issues such as data accuracy. When the metadata file is selected, the parameters can be directly recognized and read, avoiding manual input errors.
[Generate configuration file] The parameters are explained in detail as shown in the figure below:
[Tilted warehousing-Generate S3M]
Convert oblique photography model data in OSGB format to S3MB format, which can be loaded and displayed on the WebGL client after publishing the 3D service. The oblique storage function currently supports data in ENU and projected coordinate systems, but does not currently support data in plane unprojected coordinate systems. Only the coordinate conversion of the unified reference ellipsoid (projection to geography) is supported, and other coordinate system conversion is not supported, namely EPSGCode3857, and the conversion target coordinate system is EPSGCode4326. When the data of the ENU coordinate system is tilted into the database, if it is loaded on the spherical surface, the target coordinate system needs to select EPSGCode:4326. The tilt data of the projected coordinate system is stored in the database. If the tilted database result data is used in a spherical scene, the corresponding geographical coordinate system needs to be selected when entering the database, such as the original osgb data EPSGCode:4546. When tilted to the database, the target coordinate system EPSGCode must be set to 4490. Projected coordinate system tilt If you do not choose to convert the target coordinate system, the source data coordinate system will be maintained in the projected coordinate system, and its storage results can only be loaded in planar scenes.
[Oblique warehousing-generating S3M] parameters are explained in detail as shown in the figure below:
However, the process of tilted warehousing is not only for warehousing. When facing large amounts of data, tilted warehousing can also achieve data optimization, such as rebuilding the top-level merge root node to reconstruct 4^n blocks into a block file, texture Compression uses different compression methods to reduce the amount of video memory used by texture images, etc. If you are interested, you can write about it in detail in another blog, but I won’t mention it in this article for now.
3. GP model construction
1. How to build GP
[Toolbox] Right-click the operator to add it to the new automation model. When the operator parameters are not filled in, they are gray, and the model cannot be executed at this time. Double-click the operator in the automation model to open the operator in the right panel for parameter settings. Enter the required parameters and the color of the operator indicates that the model is complete and executable.
When the latter operator requires the result of the previous operator, the two operators can be connected to realize automatic execution. The execution sequence is: after the execution of the previous operator is completed, the subsequent operator will be executed, and the result can be used by the latter operator. As shown in the figure, the resulting scp file of [Generate Configuration File] can be used as the [scp path] in the latter operator parameter. Drag the [Generate Configuration File] result operator to the [Incline Storage-Generate S3M] operator to display the connection information, and select [scp path] to connect.
2. Check the result data
Execution model: When the execution progress is 100% in the task manager and the execution log displays detailed execution results, the execution is completed. In the result folder, the name of the configuration file is config.scp. Its name is default. If a name is specified, you can enter the target file name in the operator. The storage index file is GPAruk.scp. Check the result data and it is normal to enter the database.
【Result display】
