This forces Digital Atmosphere to use one of two font modes when creating station plots and contour labels:
About NCEP fonts
The NCEP raster fonts (called "raster" because they are not scalable like most Windows fonts) are stored in several key files as described below. They were used on NMC (National Meteorological Center) charts from the 1960s and are still in use today in certain National Center for Environmental Prediction products. They are stored in BMP format, so users may edit them as needed. These were extracted from NCEP source code dating to the late 1960s and may very well be some of the oldest computer fonts in use anywhere.
Additional settings for contouring may be found in Preferences > Analysis > Isopleths.