The PV‑WAVE mapping procedures let you create a variety of mapping applications. Scientific data, economic data, aerial photography data, and other kinds of data can be plotted with maps generated by PV‑WAVE, as shown in Lightning Strikes in the US.

This section discusses how to use the PV‑WAVE mapping procedures.

Typical uses for the PV‑WAVE mapping procedures include:

The mapping procedures, map datasets, and demonstration files are located in the PV‑WAVE mapping directory:

Where <RW_DIR> is the main PV-WAVE installation directory.

The PV‑WAVE mapping procedures can be adapted easily to work with your own projections and map datasets. The mapping procedures include:

This section highlights some of the concepts that are central to using the PV‑WAVE mapping routines.

For more information on mapping projections and in-depth discussions of algorithms and uses of the projections PV‑WAVE generates, refer to the following publications:

Both are available from:

A central problem facing cartographers for centuries was how to represent the features of a spherical globe on a flat map. The methods devised for “flattening” the globe onto a map are called map projections. PV‑WAVE can generate 17 different types of projections. It is also possible for you to design your own algorithms and use them in PV‑WAVE.

A map projection transforms spherical coordinates into two-dimensional X-Y coordinates. The spherical coordinates of the globe are defined by lines of longitude and latitude.

Longitude is the angle in degrees east or west of the prime meridian passing through Greenwich, England, and latitude is the angle in degrees north or south of the Equator.

For more information on the types of map projections included in PV-WAVE, please refer to the PV‑WAVE User’s Guide.

In PV‑WAVE a map dataset is a set of polylines (a series of connected points) or polygons (points which describe a filled area). These polylines or polygons can have a number of classification attributes associated with them which aid in selecting features to be plotted. These attributes allow the desired polylines or polygons for a map to be selected based on the area being mapped and the features you want to plot.

For more information on the map datasets included in PV-WAVE, please refer to PV‑WAVE User’s Guide.

The World Databank II and USGS Digital Line Graph datasets are provided with PV‑WAVE, as are procedures used to read them. To read another dataset other than World Databank II and USGS Digital Line Graph Dataset, you must write a procedure tailored to read that dataset.

The Projection keyword for the MAP procedure lets you specify a projection for the map that is drawn. PV‑WAVE provides several built-in projections, but you can also add your own projection algorithm.

To specify a projection, set the Projection keyword to the corresponding map projection index number. The map projections and their index numbers are shown in Table 8-1: Map Projections in PV‑WAVE on page 143.