The Geospatial Metadata widget is a new addition to iTwin-based viewers' information, allowing one to see coordinate reference system (CRS) information about the opened iModel or related reality data.
Image 1 - Geospatial Metadata widget example
Please refer to the individual product documentation to determine if and where such a widget is exposed in the interface. For example, in some viewers, as Design Review, that might be under Diagnostic Tools, as shown in an image.
Image 2 - Enabling Geospatial Metadata widget in Design Review through Diagnostic Tools
For developer resources, you can find the widget in My iTwins viewer already enabled together with Tree View and Map Layers panels.
Table of Contents
iModel Display Extents
Within the widget, you can toggle the iModel Display Extents in the viewport; you can learn more about this concept here.
iModel CRS
The iModel tab shows geolocation information about the loaded iModel. The expectation is that every iModel can be positioned at one permanent location on the earth. The warning will be displayed if no location information is available, as in an image.
Image 3 - no Coordinate Reference System warning
If you want to understand how geolocation is set for iModels, more information can be found in the iTwin.js documentation, including the description of each available property. Below is a short summary of key elements:
- Horizontal CRS (Horizontal Geographical Reference System) category showcases attributes set for the iModel in question, such as name, description, units, longitude, latitude, and others. As part of the overall Horizontal CRS information, two separate categories are shown:
- Datum category (Geodetic Datum) explicitly showcases geodetic datum definition information, such as name, description, ellipsoid ID, etc.
- Ellipsoid category (Geodetic Ellipsoid) explicitly showcases the geodetic ellipsoid information, such as name, description, equatorial radius, polar radius, etc.
- Vertical CRS (Vertical Geographical Reference System) category lists the name of the vertical CRS definition, which could be one of the values: "GEOID", "ELLIPSOID", "NAVD88", "NGVD29", or "LOCAL_ELLIPSOID". More information here.
- Transformation (Additional transforms) category lists additional transformations applied to horizontal or vertical coordinates. If Helmert transform was used, you should see such information in this category.
Reality Data CRS
The Reality Data tab shows geolocation information about reality data related to the loaded iModel or the iTwin. You can sort or filter by Name or Category: Attached to model, Within Extents or Outside iModel Display Extents, and expand the instance to see each geographical reference system information as shown in the image.
Image 4 - Reality Data CRS example
Reality Data types that are shown in the widget:
- Web Ready 3D Scalable Mesh (RealityMesh3DTiles)
- Cesium 3D Tiles (Cesium3DTiles)
- Cesium 3D Point Cloud (PNTS)
- Web Ready Point Cloud (OPC)
- Web Ready Terrain Scalable Mesh (Terrain3DTiles)
- Photo Navigation Mapping Resource (OPN)
- Mapping Resource (OMR)
- OSM Buildings
Warnings
Several warnings could be displayed in the Warnings tab, depending on the loaded iModel geolocation information or the iModel Display Extents.
- iModel is missing Coordinate Reference System
It is crucial to define the Coordinate Reference System to ensure accurate spatial positioning of iModel. Without defining it, iModel might have a wrong or random location on the earth's surface, which can result in misalignment and other spatial issues (Image 5). Thus, it is recommended to follow the best practice guides to validate the spatial positioning before synchronizing your engineering data. Please note that a similar warning will also be displayed in the iModel tab (Image 3).
Image 5 - iModel missing CRS warning example
- Model(s) completely outside of the extents
If one or more models are not visualized and are entirely outside the iModel Display Extents even though they appear in the Tree View, a warning message will specify the excluded models (Image 6). To learn more about iModel Display Extents and potential issues, visit this link.
Image 6 - Model outside of iModel Display Extents warning example
- Model Element(s) outside of the extents
If your model had any outlier elements that were excluded from the iModel Display Extents after synchronization, you will see a warning. This warning will only display those elements that were excluded (Image 7). To view the full content of the model, please use the standard Tree View component.
Image 7 - Elements outside the iModel Display Extents warning example
If you want to learn more about iModel Display Extents and potential issues, please visit this link. Additionally, you can find more information about excluded elements in synchronization reports provided by Powered by iTwin product you used to synchronize.