Tips and how tos for adding WMS layers into microstation V8i dgns.
Like MapInfo and ArcGIS, Microstation V8i also has the ability to display WMS (Web Mapping Service) layers as a backdrop to the views in a DGN. Microstation stores the URL and layer references to each service in a special filetype called xwms, which is basically just a text file with the .xwms extension, in which an xml fragment holding the wms spefication is written.
Microstation does appear to have a limitation with its display of WMS layers. All ILIS and NT visualiser WMS servers serve the web maps using the GDA94 Long/Lat coordinate system, however it is a common requirement to edit data in the UTM projections (such as MGA zones 52 and 53). Microstation does not handle 'on the fly' reprojections for WMS raster layers very well, as they have restrictions and cannot be moved, scaled or rotated like other raster projections.
An example of the xwms is shown below, note the WMS server url, and the layers requested from it. Because there can be many combinations of layers (particularly from the ILIS web map service), many xwms files are likely to be created for different needs.
To add a WMS layer to your DGN
1. On the file drop down menu, click raster manager
2. The Raster Manager dialog displays. Click the 'Add' icon as shown below and select 'WMS' from the drop down menu.
3. On the WMS map editor that shows, click the 'servers' button, on the next dialog, click the 'add server button and type in the address of the web mapping server you wish to connect to. The three WMS servers owned by NTLIS are as follows:
|WMS Server Address||Description|
|http://wms1.ntlis.nt.gov.au/ilismap?service=WMS&version=1.1.1&REQUEST=GetCapabilities||The ILIS maps Web mapping server. Select any combination of layers from ILIS maps.|
|http://ogc.ntlis.nt.gov.au/iws-ogc/wms?request=GetCapabilities&service=WMS&VERSION=1.1.1||The WMS server for the Imagery Catalog. Select any image from the Imagery catalog as a WMS layer.|
|http://land.visualiser.nt.gov.au/wms/wms?REQUEST=GetCapabilities||The NTLIS Google Earth server, use the NT visualiser imagery as your WMS backdrop.|
Adding a new server (click to view enlarged image...)
If you have already added the server to your list, then you can click the server button and select which server you wish to connect to from the list.
If you are prompted for proxy server credentials, then you have an issue with your Internet Explorer settings, you will need to add *.nt.gov.au to your list of proxy server exceptions. (click the image for a full zoom view of it).
4. The next step is to configure which layers you want to see from the WMS. For NT visualiser there is only one option, however the ILIS web server has many layers in its service. As shown below, make sure the webserver you requre is selected in the top drop down menu, then select those layers you want to display. Use the control button when clicking to ensure multiple selections. When done, click the Add To Map button, and arrange the order you requre the layers in, their title etc, then click the 'Attach and Save' button. (click the image for a full zoom view of it).
5. In saving the attached WMS, you will create the xwms file mentioned earlier. As shown below, you will be prompted for some details about the file (name, save location, description etc), fill in these details and click 'Save'. NOTE: Bentley Map will try to save it to your working folders on the projectwise server, if you prefer to save the xwms elsewhere, like your local drive or another common drive, click the 'cancel' button on the screen shown below and this will enable you to explore your full directory listings to select a save location.
6. on the screen that appears next, click 'Attach'
Your wms is now attached to this dgn. The xwms file you have created can be added to any other dgn if you wish, you do this in the raster manager by click File>Attach>wms and navigating to the save location of your wms.
Reprojecting WMS attachments
As mentioned above, some WMS attachments can be reprojected, but not very accurately (around 500 metres out). This is not such a problem for large scale map representations, however for testing data accuracy, reprojected WMS attachments hold no value. Of the two NTG WMS services, the NT Visualiser is capable of reprojection, however the ILIS maps WMS has not shown to.
To reproject your attached WMS (to be completed):
- Follow step 1
- Then carry out step 2
- Finally undertake step 3