Map attributes are used to customized the display of map objects in shapefiles such as basin delineations, county and state lines, and gage location points. For example, an attribute set can be defined to have major basin outlines associated with a dark green and double width line, county lines with dashed line style, and a snowmelt gage can be represented by an 'x' symbol with a blue label applied for the gage name. Note that there is more than one way to associate map attributes with a shapefile and this program supports some extensions to take advantage of additional data in the shapefile's .dbf file if it is present.