The OpenGIS® Web Map Service (WMS) Implementation Specification provides three operations (GetCapabilities, GetMap, and GetFeatureInfo) in support of the creation and display of registered and superimposed map-like views of information that come simultaneously from multiple remote and heterogeneous sources. When client and server software implements WMS, any client can access maps from any server. Any client can combine maps (overlay them like clear acetate sheets) from one or more services. Any client can query information from a map provided by any service.

1. Problems with the Extract Tool in downloads of layers
2. Internet Explorer download problems.
3. Do not have an Arc IMS license.
4. Using MapObjects IMS.
5. Do not use ESRI software.
6. Do not plan to create an internet web mapping site.
7. Data and web applications hosted by an application service provider.

1. I am using the Extract Tool in the NC OneMap viewer, but the data I would like to download don't appear in the drop-down list. What's the problem?

   There are a couple of possible reasons for this. In order for the data layer to appear in the Extract Tool drop-down box, the layer must be visible on the map ("checked on" in the layer list on the right side of the viewer). Make sure the layer is being shown on the map, then click Extract Tool button, followed by the layer you would like to download from the drop-down box at the bottom of the viewer. The data will then be clipped to the extent of what you see on the screen.

   The other reason is that not all layers in the viewer are downloadable. Currently, only data that reside on CGIA'S NC OneMap computers can be downloaded. If a layer produced by a county or city appears in the drop-down box, clicking on it will result in the county or city GIS webpage opening in a new browser window. From there the data can be downloaded, however, the data will not be clipped to the extent shown on the map.

2. Internet Explorer will not let me download certain datasets from the NC OneMap viewer. What do I do?

   If you are using Internet Explorer and your computer's operating system is Windows XP Service Pack 2, you will have to enable IE to allow the download.

3. Although our organization uses ESRI GIS software, we do not have an ArcIMS license. How can I participate in NC OneMap?

   If you are a municipality, check with your county's main GIS department. They may have the capability to serve WMS and you may be able to reach a data serving agreement, especially if your county already participates in NC OneMap.

   If you are a county or some other regional organization, check with your regional Council of Governments' (COG) GIS department to see if they are participating in NC OneMap-- they may be able to serve data in a WMS map service for you.

   You can check with some of the local application service providers (ArcIMS hosting services). If enough of their customers request the ability to serve their map services to NC OneMap via WMS, then perhaps the application service providers will start offering this capability.

4. Our organization already has an internet mapping application, but it uses the MapObjects IMS engine instead of ArcIMS. Can I serve a WMS map service to NC OneMap?

   MapObjects IMS (MoIMS) does not include this functionality. There are a number of freely available Open Source WMS map server products. You may also wish to consider having your regional COG or some other partner organization serve your layers to NC OneMap on your behalf.

5. Our organization does not use ESRI software. What are my options?

   A number of vendor supplied products and Open Source map servers either implement or comply with the WMS 1.1.0 standard. Check this page for the list of products that have paid for compliance testing so they can be listed with the OGC.

   Keep in mind that some of the products on this list are client viewers only. You will need a WMS map server. Minnesota Mapserver and deegree web map servers are Open Source software; most of the other server products on this list are not.

   Other places to look for Open Source WMS map server products that have not been listed with the OGC (it requires a fee, so not all will list) are:

   • http://freegis.org
   • http://geotools.codehaus.org
   • http://www.maptools.org
   If you are searching for an Open Source Spatially Enabled Database product (similar to SDE), you may consider using PostGIS.
6. Our organization is small and we only create a few data layers. We do not plan to create or have someone host an internet map viewer for our organization. Is there any way we can participate in NC OneMap?

   You do not have to have a customized map viewer application on your organization's website in order to serve your GIS data layers to the NC OneMap viewer. All you have to do is run a WMS map service (without a user interface) and supply on-line metadata. The NC OneMap map viewer is the user interface. You only need to run one of the Open Source map server products that support WMS. You could also explore partnering with a regional COG or some other nearby organization that has WMS map server capability if you do not feel comfortable running a WMS map server of your own.

7. We host our map viewer and map services on an application service provider's server. This company will not allow us to serve WMS map services. What can I do?

   You can still participate in NC OneMap. You could approach a regional COG or neighboring organization with WMS map serving capability and make a partnership agreement. Or, you could implement your own WMS map service capability using Open Source software without having to invest any time or effort in building a viewer/user interface.

We welcome your questions and participation.