Center for Applied Internet Data Analysis

List of Parameters (cont'd)

The data parameter is used to define the nodes and lines that need to be plotted. This can either be an URL to a data file containing all the definitions in the specified format or in the applet tag itself. All node and line definitions must be terminated by a semi-colon.

Field 1 : this field tells GeoPlot that your defining a node.

Field 2 : this field must uniquely identify each node, any unique identifier can be used.

Field 3 : latitude of the node.

Field 4 : longitude of the node.

Field 5 : the table below shows the optional attributes that can be specified for each node.

GeoPlot automatically places the title in the best possible location around the node, best refers to the area where there is the least number of lines connected to the node. The user also has the option of overriding this placement and specifying their own location. This is defined as a value following the title seperated by a comma. Commas can be placed in the title, this will not affect the final location attribute if there is one.The values correspond to the quadrant diagram shown below with the circle in the center representing the node.

Field 1 : this field tells GeoPlot that your defining a line.

Field 2 : source node

Field 3 : destination node.

Field 4 : the table below shows the optional attributes that can be specified for each node.

Types of Lines :

There are three kinds of lines that can be drawn between nodes. The simplest is just a single line between the source node and the destination node. Lines can also be drawn with both the source and the destionation referring to the same node. Such lines are depicted as circles and there can be more than one of these definitions. The maximum for a single node is 24 lines going to itself. There can be any number of lines between a pair of nodes and their definitions don't have to be together in a single block. All the indiviual lines between the nodes are drawn seperately and there is no aggregation.

By default GeoPlot places the title of a line at the locations marked 3 in the diagram above. The user can override this by specifying their own location. This is defined as a value following the title seperated by a comma. Commas can be placed in the title, this will not affect the final location attribute if there is one. In the case of circles which represent links between the same source and destination node, titles are placed by default at location 2 in the diagram shown below and there is an additional value '4' that can be specified.

By default arrows are not drawn on lines. They must be specified with the r attribute and can take any of the three values described below. Arrows are not marked on links starting and ending at the same node.

There are thirteen colors that can be expressed in words. They are listed below:

Colors can also be expressed as a RGB value.

Syntax :rgb-r-g-b

All values have to be expressed in decimal form

This picture shows how latitude and longitude usually appear on a map. The red line is the equator. All the latitudes above the equator are North latitudes, and those below are South latitudes The blue line is the Prime Meridian. The meridians to the left of the blue lines are West longitudes, and those to the right are East Longitudes.

If this were a graph in math class, you would read the bottom numbers (the X axis) first. This may seem odd, but maps are different.On a map you must read the side first to determine the latitude, and then the bottom last to determine the longitude. South latitudes and West longitudes should be specified as negative values to GeoPlot.

Explanation taken from: http://www.acs.ucalgary.ca/~dmjarvey/tutorial