When speaking about GPS resolution, there are two things you may be referring to. The first is the resolution of the screen or display, expressed as either a pixels per inch/dots per inch number, or in a height by width (#### X ####). This resolution will help determine how sensitive the screen is in touch screen models, and also how crisp and clear the image will be. The other form of resolution is a measurement of how accurate the particular GPS unit is. The best GPS units with the highest resolution, can pinpoint your exact location to within a yard as long as they have a continuous line of site to a minimum of four GPP location satellites.
For more info, see How to Select a GPS Navigation System