FIG. R-10. Residualizing methods. (a) Graphical smoothing of map contours. The difference between smoothed and actual contours localizes an anomaly. (b) Graphical smoothing of a profile. The profile should be drawn where the contours are controlled by the data and different profiles must be consistent with the smoothed regional. (c) Reading values on a regular grid and convolving with a template. Margins are lost in the process so the residual covers a smaller area than the data. Template and weighting can be varied to yield second derivative and other types of maps. (d) Template used to make the map shown in (c) above.