Proposal to Contribute WMTS Feature Info Support – Questions About Testing and terriajs-cesium Setup

[ShubhamSharmaFAO]

I’m currently working with the United Nations Food and Agriculture Organization (UNFAO), where we rely heavily on TerriaJS for our geospatial platform development. As part of our ongoing migration from TerriaJS v7 to v8, I’ve observed that WMTS support isn’t yet as mature as WMS, particularly regarding dimensions and feature info. To address this, I’ve implemented enhancements that introduce support for dimensions and feature info in WMTS services.

I’d like to contribute this work back to the community and have reviewed the contribution guidelines outlined in:
• https://github.com/TerriaJS/terriajs/blob/main/CONTRIBUTING.md
• https://github.com/CesiumGS/cesium/blob/master/Documentation/Contributors/CodingGuide/README.md

Per your guidance, I intend to break the functionality into smaller, reviewable parts, beginning with a PR focused solely on WMTS Feature Info support. Before I do that, I’d appreciate your input on a few points:
1. Test Dataset Recommendations:
To ensure my implementation is robust and interoperable, I’m looking to validate it against a diverse set of WMTS services and datasets. Do you maintain or recommend a list of public WMTS endpoints that I could use for this purpose?
2. Clarification on terriajs-cesium Setup:
I’m a bit unclear about the correct development setup for the terriajs-cesium package. The NPM package page points to CesiumGS/cesium, while I see that TerriaJS/cesium has the 8.0.2 tag and contains relevant code in its /packages directory (https://github.com/TerriaJS/cesium/tree/main/packages). Could you please clarify:
• Which repository and branch should be used when working with terriajs-cesium in a TerriaJS v8 environment?
• What’s the recommended way to set up terriajs-cesium locally (e.g., within the packages directory) for testing TerriaJS feature extensions?
3. Scope Validation:
Is “WMTS Feature Info support” a sufficiently narrow scope for an initial pull request, or would you prefer a more minimal slice for initial review?

I’m happy to adapt my approach based on your feedback and look forward to contributing. Please let me know how best to proceed.

[AnaBelgun]

@na9da

[na9da]

Hi @ShubhamSharmaFAO

Delighted to hear that you are using Terria at FAO and thanks for offering to contribute. I think implementing feature info support to WMTS would be a great addition!

I'm guessing this requires changes to both Cesium and Terria. Terria uses terriajs-cesium which is a light weight fork without any heavy modifications. So ideally the Cesium changes would go as a PR into the upstream Cesium repo. So at some point it will be good to create an issue in Cesium and work out a PR there.

To start off and make testing with Terria easier you could work from the main branch of terriajs-cesium. We have a small guide for the development set up here. Basically you need to checkout terriajs-cesium into the yarn workspace under terriamap/packages and make sure yarn install correctly links to this package from terriamap/node_modules. Let us know if you have trouble getting it to work.

Another thing to note is that our terriajs-cesium version is slightly behind the upstream. I compared the changes to WebMapTileServiceImageryProvider in upstream and it looks reasonably fine (changes since Remove deprecated API for 1.107). We'll at some point upgrade terriajs-cesium to match the latest Cesium.

As for test data, we do not maintain any WMTS endpoints ourselves. We would normally test against some publicly available ones.
This Cesium sandcastle example uses one from NASA.

So In short, once you have a local set up, please raise a PR in terriajs and terriajs-cesium. We'll meanwhile try to merge the latest updates from Cesium into terriajs-cesium. Once that looks ready you could raise another issue/PR in Cesium upstream.

Cheers,
Nanda

[ShubhamSharmaFAO]

Hello,

Thanks for your response!

I would love to provide a PR for the feature Info support for WMTS service. Unfortunately, I’m still having some trouble setting up terriajs-cesium locally for development. Here are the steps I’ve taken so far, based on the guide you shared:

• Cloned TerriaMap.
• Modified package.json as instructed:

  "private": true,
  "workspaces": {
    "packages": ["packages/*"],
    "nohoist": ["**/husky"]
  }

• Created a packages directory.
• Cloned terriajs and switched to the 8.9.3 branch.
• Cloned cesium (without switching branches).
• Switched back to the TerriaMap root folder and ran yarn install.

At this point, I noticed that linking is probably not happening correctly. In the packages directory, I have a package named cesium, but my package.json expects terriajs-cesium.

I tried a few things:

• Building inside the cesium package, hoping it would generate a terriajs-cesium package.
• Renaming the cesium package to terriajs-cesium, but encountered version mismatches.

Because of these issues, I’m unsure of the best way to properly set up terriajs-cesium for development.

Would it be possible for you to share the steps you usually take to set up your local environment? I would love to follow the same process to get everything working properly.

In the meantime, I have manually copied the terriajs-cesium folder from node_modules to the packages directory so I can continue development.

Thanks again for your help!

[zoran995]

Hi @ShubhamSharmaFAO, here are the steps that should work for using local version of terriajs-cesium

• clone TerriaMap
• Clone both terriajs and terriajs-cesium into the "packages" directory.

mkdir -p packages
git clone [email protected]:terriajs/terriajs
git clone [email protected]:terriajs/cesium terriajs-cesium

It is important to clone terriajs cesium in a directory that is not named cesium since our current default terriamap package.json expects the cesium directory. Otherwise, it will fail, resulting in incorrect linking and dependency issues between npm and Yarn. The above command will clone it in directory terriajs-cesium.

• Change the version of terriajs-cesium on both TerriaMap and terriajs.
• Change the version of terriajs-cesium-widget in terriajs.
• Make sure the terriajs version on package.json is the same as that on TerriaMap package.json. Otherwise, update this as well to ensure yarn can properly link packages.
• Add the following packages to the workspaces in terriamap/package.json:
  "packages/terriajs-cesium/packages/engine",
  "packages/terriajs-cesium/packages/widgets"
• Run yarn install, it should create softlinks for terriajs, terriajs-cesium and terriajs-cesium-widget

[ShubhamSharmaFAO]

TerriaMap still ignores my local terriajs‑cesium fork – full log of what I tried & where it fails

Thanks for providing detailed steps. Unfortunately, I am still having some issues in making the terriajs-cesium load from the packages directory.

Below is an end‑to‑end log of everything I’ve done so far to make TerriaMap load my local terriajs‑cesium instead of the registry copy. I hope the step‑by‑step detail helps highlight what I might be missing.

---

1 · What I’m ultimately trying to do

Live reload and ensure terriajs-cesium is picked up from the packages/ directory, not from node_modules.

---

2 · Environment

Tool	Version
Node	20.14.0
Yarn (Classic)	1.22.22 (workspace: supported) or 1.18
TerriaMap	main
terriajs	(workspace)
terriajs-cesium	8.0.2 (local engine package)
terriajs-cesium-widgets	5.0.1

---

3 · My Cloning & Directory Layout

# root of TerriaMap repo
mkdir -p packages
git clone [email protected]:terriajs/terriajs  
git clone [email protected]:terriajs/cesium terriajs-cesium 

packages/
├─ terriajs/
└─ terriajs-cesium/
    └─ packages/
        ├─ engine/   (name: terriajs-cesium, version: 8.0.2)
        └─ widgets/  (name: terriajs-cesium-widgets, version: 5.0.1)

---

4 · What I Tried

Updated TerriaMap/package.json:

"workspaces": {
  "packages": [
    "packages/terriajs",
    "packages/cesium",
    "packages/terriajs-server",
    "packages/plugin-sample",
    "packages/terriajs-cesium/packages/engine",
    "packages/terriajs-cesium/packages/widgets"
  ],
  "nohoist": [
    "**/husky"
  ]
}

I experimented with:

• Removing cesium entirely.
• Using packages/* as a blanket rule.
• Several combinations of paths in workspaces.
• Different versions of yarn
• Adding workspace identifier in packages

The results:

• Either fails at the copy-cesium-workers step during the terriajs build.
• Or loads terriajs-cesium from node_modules instead of the local copy.

---

5 · Version Consistency Checks

• Verified I’m using the correct terriajs branch (8.9.3).
• Local terriajs-cesium and terriajs-cesium-widgets packages match expected versions.

In terriajs/package.json:

"terriajs-cesium": "8.0.2",
"terriajs-cesium-widgets": "5.0.1"

In TerriaMap/package.json:

"terriajs-cesium": "8.0.2"

---

Please let me know if you have any insight into what’s missing or where resolution steps might be going wrong

Thanks! 🙏

[zoran995]

Hi @ShubhamSharmaFAO, sorry I missed mentioning the commands you need to run it in terriajs-cesium directory.

cd terriajs-cesium

npm run release
# OR
npm install
npm run build
npm run build-ts

After that, you should be able to install it correctly. For the continuous build of Cesium changes, you can try running npm run build-watch from terriajs-cesium directory, and it should rebuild Cesium on file change (haven't tried it). But you will still need to manually run npm run build-ts to generate type definitions, as Cesium doesn't have an option to run it in watch mode.

p.s. We are also trying to update this part of the guide, you can check it here https://github.com/TerriaJS/terriajs/pull/7612/files

[ShubhamSharmaFAO]

Thanks for the support works flawlessly!