|1998 Isopleth Maps
The 1998 isopleth maps are available as gif images and as Adobe Portable Document Format (pdf) files. The gif images are smaller (about 50K each) and will download quicker. The pdf files are larger (about 200K each) but are higher resolution. The pdf files are a better choice if you plan to print the maps. Pdf files also require the Acrobat Reader software from Adobe.
Click on one of the following to look at 1998 maps: