WT (Web Tile)

GISBox is a one-stop 3D GIS data editing, conversion and publishing platform that supports editing in multiple GIS formats such as OSGB/GEOTIFF/RVT, converting to 3DTiles/Terrain and publishing.

Introduction

WT file is a tile data format mainly used for 3D tile maps and geographic information systems (GIS), designed for efficient display and distribution of large-scale geospatial data. This file format is the abbreviation of Web Tile and is widely used in web-based 3D visualization platforms and geospatial applications. Especially in GIS platforms such as Wings Engine, the WT format is adopted to efficiently distribute large-scale 3D city models and geospatial data.

File Structure

WT files divide geospatial data such as 3D models, textures, and metadata into tiles and manage them in a hierarchical structure. This allows large city or terrain models to be efficiently distributed in a streaming manner.

Main components of WT files:

1. **Metadata: **Records tile information (position, size, LOD), coordinate system information, and attribute information.
2. **Model data: **3D models are stored in glTF (GL Transmission Format) or b3dm format.
3. **Texture: **Contains compressed high-resolution texture data in jpg, webp, or ktx2 format.
4. **LOD (level of detail) management: **Each tile has a different LOD and can automatically display the most appropriate resolution based on the viewing distance.

Pros

1. Streaming loading, efficient display: WT files are streamed in tile form, so even large 3D models can be easily displayed.
2. On-demand loading, saving memory: Only tiles within the field of view are loaded, rendering is fast and memory consumption is low.
3. Automatic LOD management: Automatically adjust LOD according to the viewing distance to balance performance and image quality.
4. Dynamic resolution of near and far views: The far view is displayed at low resolution, and the near view is displayed at high resolution, effectively reducing the rendering load.
5. Efficient compression and transmission: Use webp or ktx2 texture format to effectively reduce file size and speed up network transmission.

Cons

1. Complex pre-processing: Creating WT files requires tiling the source data (FBX, OBJ, etc.) and configuring LOD. This pre-processing process is time-consuming and resource-intensive.
2. **Compatibility limitations: **WT files are mainly used in GIS platforms such as Wings Engine, and have limited support in other general GIS software.
3. **Lack of native support: **Platforms such as Esri ArcGIS do not natively support the WT format and require format conversion.
4. **Incompatibility with some devices: **Some older browsers or devices may not support the compression format used by WT files (such as ktx2).

Application Scenario

In urban planning, the WT format can be used to manage 3D city models and achieve high-speed visualization on the Web platform. This can accurately display the height and layout of buildings, facilitating landscape simulation and sunshine analysis. In disaster response, 3D maps in the WT format can be used to visualize the impact of earthquakes or floods and view the conditions of the affected areas in real time. In addition, by integrating it with aerial imagery or satellite data, detailed terrain information of the affected areas can be quickly confirmed. In traffic management and navigation, the WT format can be used to display tiled 3D road maps, which can load high-precision road models at high speed, thereby improving navigation accuracy and real-time performance.

Example

1. Data structure examples.

2. File example.

Related GIS files

MID

IMDF

STYLX

E00

References

1. https://fileinfo.com/extension/wt
2. https://file.org/extension/wt
3. https://filext.com/file-extension/WT