How to load 3d building corrected coordinates

Cesium ion
1

Hello, I want to load 3D buildings with the correct coordinates in Cesıum, but in the solid model, the coordinates come from somewhere else. Even though when you load the point cloud it arrives at the correct coordinates. I tried to do it with codes but I couldn’t do it

2

Hi, if you can provide us with some more information it will help

  • What program are you getting your data from?
  • What format is your data in?
  • Do you know the coordinate system that your data is in? Or do you just need to see the data in place and adjust it manually.
3

Hello, I get it as .obj from the DJI Terra program, my coordinate system is ITRF96. I do not have any projection problems in CAD programs. I receive data in the correct coordinates. Even in Cesium, the point clouds are in the correct coordinates, but the solid model comes without coordinates. As you know, since precision is very important, manual scrolling will mislead.

4

By the way, my drone is DJI 300 matrix RTK also makes location-based measurements.

5

So if I understand your issue correctly, you are trying to import and align two assets:

  1. a point cloud scan that is in the ITRF96 coordinate system. This is positioned at the correct position
  2. a .OBJ file that contains a building that does not have any coordinate system included.

The easiest way to set the location of the OBJ asset is to use the ion website.

Click the Adjust Tileset Location in the details view of the asset. without coordinates.

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This will give you options to set the latitude/longitude/height as well as adjust the orientation.

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The ion REST API also includes an option to set the position when you upload an OBJ file for the 3D_CAPTURE or 3D_MODEL options.

6

The .obj file also has coordinates, but when you download it from Cesium.ion, it comes without coordinates. My coordinates are not local coordinates. Since I work with 2-3cm precision, manual adjustments lead to errors.

7

At this time Cesium ion does not support coordinate systems embedded into OBJ files. This may be a feature we add in the future if there is enough interest in it. We would like to know more about the details of your use case to help us understand better.

  • Can you provide an asset id of the OBJ file you uploaded with the coordinate system data embedded in it? That will help us know what format you are using to embed the coordinates.
  • Do you know what coordinate system the OBJ is using?
  • To confirm the OBJ was from the DJI Terra program

With Adjust Tileset Location you are able to type the position of the asset with 8 or more decimal places. That will provide sub-centimeter accuracy. If you are able to determine what the origin of the OBJ coordinate system is in latitude longitude you could still maintain the accuracy.