DTVF: Troubleshooting

This page offers some solutions for common issues, and answers to common questions, that may arise when using the DTVF. These are listed here (on the GitHub wiki), rather than within committed README files as they may be useful for all uses of the framework, regardless of mapping provider, or pertain to multiple versions of the code.

Potential issues/questions relating to all uses of the framework, regardless of map provider, are listed first; solutions that only pertain to individual map providers are listed in further sections.

Generic

This section is relevant to all uses of the DTVF, regardless of the selected mapping provider.

Issue/Question	Solution/Answer
Visualisation not updating after changes	Try clearing (or disabling) your browser cache before reloading the page.
Visualisation not updating after changes	If running the visualisation within a Docker container, you may need to rebuild the Docker image and run a new container to see recent file changes.
No data is shown	If no data is shown and no layer tree is built then this suggests that one (or more) of the user defined JSON files is invalid. Please use an external validator tool (or website) to ensure that the JSON is valid.
Hovering over a feature does nothing	The framework supports mouse hovering effects if the input data contains certain metadata fields. To show a small description box the geospatial data needs to contain a name and description field.

Mapbox

Issue/Question	Solution/Answer
What URL do I use to load content from GeoServer?	TBD
How do I setup data-driven styling?	TBD

Cesium JS

This section is relevant to issues/questions that only arise when developing Cesium JS visualisation with the framework.

Issue/Question	Solution/Answer
Do my data files have to be hosted online?	Cesium requires a valid URL to load data files, this does mean that they have to be accessible online. However, data files can be included within the visualisation container (which uses Apache to host a web server) so that they can be accessed via a URL relative to the visualisation's hosted directory (i.e. "/data/tileset.json").
Getting a 401 (Unauthorized) error	If the URL causing the error is an attempt to use a Cesium API key, then this is expected. The desire here is that we want to ensure that we're not using a Cesium Ion key.
3D data is not showing	Depending on the format, some data may specify object locations relative to a position defined outside the data itself. If not set, this can cause the 3D data not to appear. Within the source node of the visualisation configuration, please ensure the position (an array of longitude, latitude, and height) is set.
3D data is in wrong rotation	At the time of writing, specifying a rotation at visualisation time is not supported. Users will need to ensure that their data contains the correct rotation within the files themselves.
Features appear to be floating	For many data formats (such as 3D tile sets), Cesium JS does not provide an easy option to change the height of its data. Official advice appears to be that developers need to ensure the elevation of their data is correct (factoring in the specific terrain model that will be used), when the data file is generated.
How can I style my 2D data?	Unlike Mapbox, Cesium JS does not provide any functionality for styling 2D data on the client side. Instead, styling of any data provided by WMS endpoints must be done within Geoserver. For more information on server-side styling, read the page here.
Visualisation is very unresponsive/slow to render	There's two possibilities here, either you're plotting too much data at once, or you need to invest in a better GPU; unfortunately, Cesium has a high GPU overhead.
Can I display 2D vector data?	Cesium does not provide an easy way to inject and display 2D vector data (particularly from WMS or WFS endpoints). GeoServer can host the vector data, but when used Cesium will rasterise it as a single, flat PNG before visualisation. Whilst it may be possible in future (with significant development), this is not something offered by the framework at the time of writing.
Getting a 422 (Unknown) error	This can sometimes happen when Cesium contacts the Mapbox styles API, especially at close-up zoom levels. Unless this is causing any visual issues, it should be safe to ignore.