it is a contour line of elevation Control index contour, or just index contour
What are the difference's between contour interval and index contour?
index contour lines have numbers contour lines dont
An Index Contour
an index contour.
index contour
the contour interval is the difference in elevation between contour lines that are next to each other
A thicker line that has numbers written on it showing the rising or decreasing elevation on a topographic map By Ash Every fifth contour line on a topographic map, usually thicker, used to label elevation.
It makes it easier to count the number of contour lines.
The numbers of contour lines indicate altitude or elevation along that line.
The darker contour lines on map are called index contour lines. Numbers that indicate elevations are often written on these lines.
Index contours can be identified by every 5th contour line and also because its darker and heavier