Example of Background Map Options
Every flat map misrepresents the surface of the Earth in some way. Maps cannot match a globe in truly representing the surface of the entire Earth. A map projection is used to portray all or part of the round Earth on a flat surface. This cannot be done without some distortion. Every projection has its own set of advantages and disadvantages. A map can show one or more, but not all, of the following: true direction, distance, area, or shape. JMP uses a couple of projections (Albers Equal Area Conic and Kavrayskiy VII) for its maps. Within Images, you can select from two built-in map images, or you can connect to a Web Map Service to retrieve a background image.
Examples of Simple and Detailed Maps
Simple Earth and Detailed Earth both support a geodesic scaling. In Examples of Simple and Detailed Maps, the Earth appears as a rectangle, where the width is twice as wide as the height. If we were to take this rectangle and roll it up, we would have a cylinder. In reality, we know that the Earth does not form a cylinder, but rather a sphere. You can use a geodesic scaling, which transforms the map to a more realistic representation of the Earth. To use the geodesic scaling, change the type of scale on the axes.
To change the axes scale:
Change the Scale Type to Geodesic or Geodesic US.
Y Axis Setting Window
Simple Earth Background Map - Axes Set to Geodesic Scale
Examples of NASA and WMS Maps
NASA Server Map Example
NASA Server Map Example - Zoom In on Colorado
To locate a server, launch the add-in through the menu items Add-Ins > Map Images > WMS Explorer. The add-in presents a text box for entering the url of a known WMS server. Alternatively, you can make a selection from a drop-down list of pre-discovered WMS servers (the list can be out of date). After specifying a WMS server, select Get Layers. Using Get Layers is not necessary if selecting from the drop-down list or if clicking Enter after entering a URL. This sends a request to the WMS server for a list of layers that the server supports. The returned list appears in the list box on the left, labeled Layers. A map of the world appears as an outline in the graph to the right. Selecting a layer makes a request to the WMS server to return a map, using the specified layer, that represents the entire earth. Selecting a different layer generates a different map.
Example of U.S. State Boundaries
Right-click a blank area on the graph and select Background Map (or select Graph > Background Map in Graph Builder).
Select Simple Earth, Detailed Earth, NASA server, or Street Map Service in the Images column.
Select Web Map Service and paste a WMS URL next to URL. Enter the layer identifier next to Layer.
Gradient Settings Window
Change the Color Theme or define a custom color theme.
Specify the Number of labels that you want to include. The default value of zero means that all labels are shown.
Choose a Scale Type:
Choose a Range Type:
Specify the Minimum, Center, and Maximum values in your gradient.
Select Horizontal to change the orientation of the gradient colors in the legend.
Select Reverse Colors to flip the color theme.
Select Reverse Scale to flip the values of your gradient.
Select Discrete Colors to produce a stepped gradient.