Web Map Service (WMS)

WMS (Web Map Service) is a standard defined by OGC (Open Geospatial Consortium) for the presentation of map images over the web. WMS can be displayed as a part of a model, either as background images in plan(2D), or draped to terrain surfaces in 3D.

Find it here:

The WMS Tool

Before WMS can be displayed, a task defining the data source must be created with the “WMS Tool” from the “Insert” menu.

Task

• Templates - Some configurations will have pre-defined templates ready for use. User-defined templates will also appear in this list - see separate section.

• Name - Give the task a descriptive name - e.g. “WMS”. This is the name that will appear in the task tree.

• Subtask of: Select the task from the dropdown list and your WMS task will be stored as a subtask of this. By placing the cursor on a task when starting the WMS tool, this will automatically be selected as default.

WMS Settings

• Url - Displays the Url string to the WMS Service - use “Select Layer” to change

• Layers - Displays the selected layer(s) - use “Select Layer” to change

• Select Layers - WMS Service Url: Input the Url string to the WMS provider. It is not necessary to input more information beyond the “?” as the current version does not yet support pre-set configurations. Press the “Select Layers” icon; the tool will perform a so-called GetCapability request to the server, and the message “Loading WMS Capabilities” should appear at the bottom of the dialogue. If the URL is valid, the “Select Layers” part should display information about available layers.

• Select Layers - With a valid connection, the WMS service will return a list of layers. Mark the layers to include in your setup. Be aware that a layer must have a corresponding “Layer ID” in the right column to be valid. If the “Layer ID” is blank, it contains no data and is only included for organizational purposes.

Data Settings

• Quadri Model CRS - Displays the CRS of the Quadri Model, usually identified by an EPSG code.

• WMS CRS - Displays the CRS options received from the WMS Service. If the model CRS is found in the list from the WMS service, this CRS will automatically be selected. If a corresponding CRS is not found, one can still try to select a CRS from the list. Novapoint will then try to perform a transformation, but there is no guarantee that Novapoint will find a suitable match for the CRS in question. In cases where transformations are used, it is important to check the accuracy of the resulting tiles.

• Refresh Data - Removes the existing cache and starts downloading new tiles.

Draping

• Select features - If the WMS images are to be draped on a surface for 3D viewing, select the features with this function. Draping will only work with surface features.

Finish

• Preview 2D/3D - The result can be previewed in 2D/3D with this function. The preview button will not be enabled before the tool has the minimum of necessary input. The 3D button will not be enabled if there is no surface attached.

• Finish - This function will store the information in the task tree. The finish button will not be enabled before the tool has the minimum of necessary input.

Using WMS with models

The WMS Task will appear in the task tree in the Explorer Window. Select any combination of data in the task tree (by holding Control) together with the WMS Task. Then right-click and select “View in 3D” or “View in Plan” to draw data. WMS can also be stored in a Plan Presentation or a 3D Presentation.

Tile downloading

The image downloading is dynamic, It only downloads the requested image tiles depending on your view and zoom level. First-time image downloading may take a while, depending on the performance of the WMS Service and your Internet connection speed. Once tiles are downloaded and saved to the cache, views will reuse these at a much more sufficient speed.

Shared Worksets

On shared worksets, only tasks are shared. Each user must retain a folder with locally cached images.

Create user-defined templates

By right-clicking a WMS Task and selecting “Save as Template” the setup will appear in the list of templates. They can now be reused to create new WMS tasks in new Quadri models, given that they belong to the same CRS.

Cache Management

There is no cache management in the current version.

Problem Solving

The most recurring problem related to using of WMS is wrong CRS settings. Public WMS services also vary a lot in both quality and speed.

If you experience that the WMS is not showing, it could be that the service is not working at the moment. You could also try to go to the explorer and start to edit the WMS task used in your presentation.

If you get a message about the CRS/Layers do not match and the OK button is Gray, then the CRS/Layer in the task is not supported by the service anymore. Please define new CRS/Layers for this service in the tool.

If that was not the case, you could try to use the button in the tool to refresh the cache.

Resources

• Wikipedia - Web Map Service

• OGC - Web Map Service Interface Standard (WMS)

Next topic: WMTS (Web Map Tile Service)