# About merge terrain file

**URL:** <https://community.cesium.com/t/about-merge-terrain-file/24877>\
**Category:** 3D Tiles\
**Created:** [June 19, 2023, 8:40am UTC](https://community.cesium.com/t/about-merge-terrain-file/24877 "2023-06-19T08:40:43Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Origin\_plan](https://sea2.discourse-cdn.com/cesium/user_avatar/community.cesium.com/origin_plan/32/3476_2.png) [@Origin\_plan](https://community.cesium.com/u/Origin_plan)\
**Post date:** [June 19, 2023, 8:40am UTC](https://community.cesium.com/t/about-merge-terrain-file/24877/1 "2023-06-19T08:40:44Z")

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My terrain is in quantize\_mesh format.  
First,I make a terrain to level 0~10 (named q1),then make this terrain to level 0~14(named q2).  
Second, I copy q2’s level 11~14 to q1,then copy q2’s layer.json to q1.  
Next, use q1 in cesium.However, requests at levels 11-14 are not displayed in cesium. why?And files with the same name are in the q1 and q2 are different.

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**Author:** ![Kevin\_Ring](https://sea2.discourse-cdn.com/cesium/user_avatar/community.cesium.com/kevin_ring/32/2003_2.png) [@Kevin\_Ring](https://community.cesium.com/u/Kevin_Ring)\
**Post date:** [June 21, 2023, 2:08am UTC](https://community.cesium.com/t/about-merge-terrain-file/24877/2 "2023-06-21T02:08:31Z")

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quantized-mesh tiles can and usually do have information about availability of other tiles embedded in the tiles themselves. You can’t combine them just by copying like this.

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<div class="post-metadata">

**Author:** ![Origin\_plan](https://sea2.discourse-cdn.com/cesium/user_avatar/community.cesium.com/origin_plan/32/3476_2.png) [@Origin\_plan](https://community.cesium.com/u/Origin_plan)\
**Post date:** [June 21, 2023, 2:16am UTC](https://community.cesium.com/t/about-merge-terrain-file/24877/3 "2023-06-21T02:16:43Z")

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Follow [GitHub - CesiumGS/quantized-mesh: Specification for streaming massive terrain datasets for 3D visualization.](https://github.com/CesiumGS/quantized-mesh) .It doesn’t seem to indicate which part of the file is used to store other tile information.

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<div class="post-metadata">

**Author:** ![Kevin\_Ring](https://sea2.discourse-cdn.com/cesium/user_avatar/community.cesium.com/kevin_ring/32/2003_2.png) [@Kevin\_Ring](https://community.cesium.com/u/Kevin_Ring)\
**Post date:** [June 21, 2023, 6:18am UTC](https://community.cesium.com/t/about-merge-terrain-file/24877/4 "2023-06-21T06:18:49Z")

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It’s stored in the Metadata extension. Unfortunately that’s not very well documented. The best reference is the CesiumJS source code:

> <https://github.com/CesiumGS/cesium/blob/51307b2630ed3c74d41d03ed82ef0332a72f16b0/packages/engine/Source/Core/CesiumTerrainProvider.js#L795>