On a topographic map what indicates the difference in elevation between adjacent lines

The Contour Intervals (CI)

Explanation:

In topographic maps contours represent an Isoline of elevation data, but because there can be many contour lines in a given map and they would densify the information represented not every contour line is labeled with their elevation. Index Contour lines are the ones that are labeled the other contour lines are still drawn but not labeled therefore to know the distances between adjacent contour lines and not just index contour lines the topographer indicates in the maps through Contour Intervals.

Contour intervals can be easily calculated by getting the difference between two adjacent Index Contour lines and then dividing by the number o contours between both index lines plus 1.

Example

CI= (1200m - 1000m) / 4 + 1 = 200m / 5

CI= 40m

the first phase of the government’s plan for settlement was building the transcontinental railroad. the railroad provided a way to bring settlers and manufactured goods west and ship their agricultural and mining produce east. the transcontinental railroad was an essential artery for rapid development of the frontier.

the second phase of the government’s plan was a liberal land distribution policy that made it possible for many people to homestead. with these two key elements—transportation and cheap land—the government rapidly achieved its goal of persuading people to move west, settle on farms, and push back the frontier.