A seismic acquisition line that differs from straight by a significant amount. Care must especially be exercised where (a) the offset (source-to-geophone) distance is sufficiently different from distances measured along the line that normal-moveout corrections are significantly in error, or where (b) cross-dip is large enough to confuse inline dip measurements and cause significant error in dip calculations. Crooked lines tend to result in crossline smear. Lines are sometimes deliberately made crooked so that cross-dip as well as inline dip can be determined. Figure C-18 shows a crooked-line plot, also called a scattergram.