How the maps are made
Each map comes from a six-character code. The page invents the land for that code: a main hill, a ridge or two, a stream running down a valley to the map edge, and in about half the maps a closed hollow. Contours are drawn at one interval, with every fifth line thicker and labeled, plus a scale bar, north arrow and bench mark. Every answer is worked out from that same surface.
Lines never cross, and every V where the stream crosses a line points upstream.
Example: gradient between two points
On map K7Q2MX, point A is on the 1440 ft contour line and point B is on the 1520 ft line, so the change in elevation is 80 ft. On the scale, A to B is about 0.93 mile. Gradient = change in field value ÷ distance = 80 ft ÷ 0.93 mi = 86 ft/mi. A ruler is never exact, so the key accepts 81.9 to 90.6 ft/mi, the way Regents rating guides give a range. Open this map.
For a class
Share with class copies a link to the same map and questions. To stop copying on paper, set Maps to a number before you print: each student gets a different map with the same kinds of questions, and the keys print at the end. Untick questions you have not taught yet.
Questions people ask
How do you find the contour interval?
Take two labeled lines, subtract their elevations, and divide by the number of steps between them. From 500 ft to 600 ft with four thin lines in between is five steps, so the interval is 100 ÷ 5 = 20 ft.
How do you find the highest possible elevation of a hill?
Find the highest closed line around the top. The top is above that line but below the next one, which would have been drawn if the hill reached it. Inside a 600 ft line with a 20 ft interval, the highest possible elevation is 619 ft.
Which way does a stream flow on a topographic map?
Where a stream crosses a contour line, the line bends into a V that points upstream, toward higher ground. The water flows the other way, crossing the lines from higher to lower elevations.
How do you calculate gradient?
Gradient = change in elevation ÷ distance. Read the elevation of both points, subtract, and measure the distance between them with the scale bar. A drop of 200 ft over 0.5 mi is 400 ft/mi.
How do you draw a topographic profile?
Lay a strip of paper along the line, mark each place a contour line crosses it, and write its elevation. Move the strip to the grid, plot each mark at its elevation, and join the plots with a smooth curve. Hilltops and valleys go past the last plot, but by less than one interval.
What do the short ticks on some contour lines mean?
They are hachures, and they mark a depression: a closed hollow with no outlet. The ticks point downhill, into the hollow.
Is this the Regents exam format?
Mostly. Contour interval, point elevations, gradient, steepness, stream direction and profiles all appear on past Physical Setting / Earth Science Regents exams (newest: June 2026). Highest possible elevation is a class exercise. Drawing contour lines through given elevations, also common on the exam, is not here yet. Earth and Space Sciences exams have had no contour maps so far.
Sources: NYSED Physical Setting / Earth Science Regents exams and rating guides, 2012 to June 2026; NYSED Earth and Space Sciences Regents exams, June 2025 to August 2026; Reference Tables for Physical Setting / Earth Science, 2011 Edition; Reference Tables for Earth and Space Sciences, 2024 Edition; USGS Topographic Map Symbols (PDF); USGS US Topo specifications: elevation. Checked October 24, 2026.