Web Mapping Service
The Web Mapping Service (WMS) standard offers a great way to access maps and aerial photos from online WMS compliant servers. There are paid servers, but many states now provide access to maps and aerial photos at no cost via WMS. The first thing to do is to select the WMS server. This is done from the Layers tab. Then go through the Layers tree control and select the individual layers that you want to display. Finally, go to the Bounding Box Tab and set the pixel size so that the pixel width and height does not exceed 2000.
WMS images will automatically be georeferenced to either UTM or State Plane coordinates. The destination coordinate system is selected from the View Options dialog. Be sure to select the State Plane zone or the UTM zone and hemisphere before trying to insert a WMS image.
WMS URL - URL address for the WMS servers. You can select from one of the default URL's that are presented by default in the WMS dialog box or enter another URL into the row with the start at the bottom of the URL list. After entering the URL, hit the header column to the left and a layer list will be generated in the list box below.
Layers - The layer list is generated to show the layers in the selected WMS URL. Each layer is listed, along with all of the available format styles. Place a check box next to the layers that you want to display. You can only select from one WMS URL in each WMS plot object. To access layers from other URLs, simply create another WMS object by selecting Insert -> WMS Layer...
Bounding Box Tab
Pixel Size - This is the pixel size in meters. The smaller the pixel size, the more detail you will see in the image, however there is typically a limit in the number of pixel size of images that servers will allow you to download. Typically, this is about 2000 pixels wide or high. If after leaving the WMS dialog box, you find that the image does not appear then try increasing the pixel size in order to reduce the number of pixels.
Coordinates of the Bounding Box - These coordinates will be used in the request for a map image. If you hit the update button, it will automatically set the coordinates to bound the current view.
Hemisphere - Select either the southern or northern hemisphere.