numerical markings造句

Different railroads used different sized nails with either alpha or numerical markings.
"' Numerical marking "'is the manner of denoting the arithmetical values of contour lines.
To maximize readability of contour maps, there are several design choices available to the map creator, principally line weight, line color, line type and method of numerical marking.
It's difficult to find numerical markings in a sentence. 用numerical markings造句挺难的