Model article: tilt photography

Oblique image refers to the image obtained by an aerial camera with a certain inclination angle. Aerial oblique images can not only truly reflect the ground characteristics, but also greatly expand the application field of remote sensing images by adopting advanced positioning technology, embedding accurate 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. I won't elaborate on his main features here, but mainly talk about how to access, optimize and publish tilt photography data in SuperMap.

In the hypergraph iDesktop 9D(20 19)? In version 9. 1. 1, the related functions of tilt photography data are concentrated in the position shown below.

In SuperMap iDesktop, the 3D model cache file is in *. Load scp format to realize direct batch loading and browsing of oblique photography data.

1. If there is a *. Scp configuration file, you can import tilt photography data through Start-Data Import-Tilt Photography in the menu bar;

2. If there is no configuration file, you can generate scp configuration file through SuperMap iDesktop. In the drop-down button of 3d data-tilt photography-configuration file, click Generate Configuration File to open the dialog box as shown in the figure below, where you can perform projection, projection conversion and set the position of the center point of the model.

It is worth noting that if there are subfolders in the source path, the subfolders containing OSGB files will be added to the folder list with an *. The scp configuration file will be generated.

In addition, in iDesktop, you can click "OBJ→OSGB" in the drop-down buttons of "3D Data"-"Tilt Photography"-"Type Conversion"? OBJ format oblique photography model data derived from PhotoScan is converted into OSGB format data.

In iDesktop, the processing of tilt data mainly includes three functions under "3D data"-"tilt photography"-"data processing", which are briefly described as follows:

By modifying the coordinate information of the data itself, it can be used to solve the problem of multiple center points of oblique photography data in the same survey area, and realize the requirement of loading all data in one SCP configuration file. It is only applicable to the oblique photography model configuration file with projection information set, and the projection information can be set for the model in the above-mentioned "Generation Configuration File".

The parameters are configured as follows. Finally, a configuration file with the same name as the source SCP file and *. Osgb files stored in various folders will be generated in the specified output directory.

When the model is divided into many root nodes because of its wide spatial range and huge data volume, it takes a long time to read these root nodes, which leads to the slow loading of the model, so it can be used at this time.

The function of "merging root nodes" will improve the loading efficiency. Its essence is to merge the root nodes in a certain spatial range into one root node, that is, to generate a thicker LOD hierarchy through upward refinement, and the number of root nodes in the model is reduced by about1/4 of the original number each time; The number of merges corresponds to the pyramid level below. If you need to use tilt data in iServer, the Target Configuration Profile here should be set in the same directory as the source profile.

When the data range of oblique photography models is large, it takes a lot of memory resources to load and display these models at the same time. "Generating proxy nodes" provides a dynamic display scheduling strategy for loading oblique photography models, and generates proxy nodes and new configuration files without model data. When the user moves or zooms, once the viewport of the 3D scene changes, the program will update the model to be displayed in real time, which can greatly improve the display efficiency of the oblique photography model and reduce the memory occupation.

Among them, the generation point series is used to set the proxy node series, and it is recommended to set it to 3 ~ 5; Like merging root nodes, the Target Profile needs to be set in the same directory as the source profile to avoid errors in iServer.

Through the above two parts, tilt data has been imported into iDesktop and processed accordingly. So, how can I publish it on iServer? Now we basically use iClient for WebGL for 3D B/S development.

1. Perform texture compression on the original oblique photography model data in OSGB format through the "compression simplification" function to generate S3M data. To ensure the success of a generation. The scp file to be set can be linked to the corresponding OSGB data, and the target path is the same as the path where * is located. The scp file has been located.

After generating S3M data, add it to the spherical scene, save the workspace, publish it to iServer, and select 3D service.

2. You can also add oblique photographic data to the scene, and then generate a scene cache, and directly publish the generated workspace as shown above.