Surface weather analysis isotherms (lines of equal temperature), and isotachs (lines of equal wind speed) are drawn. The abstract weather symbols were devised to take up the least room possible on weather maps. A synoptic scale feature is one whose dimensions are large in scale, more than several hundred kilometers in length. Migratory pressure systems and frontal zones exist on this scale. Centers of surface high- and low-pressure areas that are found within closed isobars on a surface weather analysis are the absolute maxima and minima in the pressure field, and can tell a user in a glance what the general weather is
Smith chart the centre of the Smith chart. The length of the line would then be scaled to P assuming the Smith chart radius to be unity. For example, if the actual radius measured from the paper was 100 mm, the length OP would be 63 mm. The following table gives some similar examples of points which are plotted on the "Z" Smith chart. For each, the reflection coefficient is given in polar form together with the corresponding normalised impedance in rectangular form. The conversion may be read directly from the Smith chart or by substitution into the equation. In RF circuit