Hi,
I've got GoogleEarth running in another window on my machine as I write.
I will give the metric elevation of a few landmarks in Manhattan:

Central Park Reservoir 36 meters

Columbus Circle 21-22 meters

8th Ave & 53rd St. 18 meters

8th Ave & 47th St. 12 meters

8th Ave & 38th St. 10 meters

8th Ave and 31st St. 8 meters

8th Ave & 25th St. 6 meters

8th Ave & 20th St. 4 meters

Washington Square Park 6 meters

3rd Ave & E.14th Street 8 Meters

3rd Ave and E.24th Street 6 meters

3rd Ave & East38th St. 9 meters

3rd Ave & E.44th St. 11 meters

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East Houston Street and Avenue D 1 meter

East Houston Street and Avenue C 3 meters

East Houston Street and Avenue B 5 meters

East Houston Street and Avenue A 7 meters

East Houston Street and 2nd Avenue 10 meters

Bleecker Street and Bowery 11 meters

Lafayette St. and East Houston St. 10 meters (I can see the bike lane in the Satelite photo)

Lafayette St. and East 4th St. 11 meters

Lafayette St. and Astor Place 10 meters

4th Ave & 12th street 10 meters

Union Square Park 10 meters

Broadway & East 23rd St. 10 meters

Broadway & West 28th St. 11 meters

Broadway & West 34th St. 12 meters

Broadway & West 36th St. 13 meters

Broadway & West 37th St. 14 meters

Broadway & West 39th St. 15 meters

Broadway & west 44th St. 14 meters

Broadway & west 50th St. 15 meters

Broadway & west 51st St. 16 meters

Broadway & West 52nd St. 17 meters

Broadway & west 53rd St. 18 meters

Broadway & west 55th St. 20 meters

Broadway & west 57th St 22 meters

Columbus Circle 21 ~ 22 meters

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I am running Google Earth in another window. The following are intersections in Manhattan followed by the Elevation above Sea Level in Meters:
Columbus Circle_________________21~22 meters

Central Park W & W 62nd St.______20 meters

Central Park W & W 67th St_______23 meters

Central Park W & W 72nd St_______ 25 meters

Central ParK W & W77th St________23 meters

Central Park W & W 81st St_________27 meters

Central Park W & W 83rd St_________30 meters

Central Park W & W 84th St_________32 meters

Central Park W & W 85th St_________33 meters

Central Park W & W 88th St_________34 meters

Central Park W & W 90th St_________35 meters

Central Park W & W 93rd St_________33 meters

Central Park W & W 95th St_________29 meters

Central Park W & W 97th St_________28 meters

Central Park W & W 101st St________21 meters

Central Park W & W 103rd St________27 meters

Central Park W & W 105th St_______29 meters

Central Park W & W 107th St________22 meters

Central Park W & W 109th St________15 meters

Central Park W & W 110th St________13 meters

(note: Central Park west becomes Frederick Douglas Blvd at 110th street)

Frederick Douglas Blvd & W 112th St_____11 meters

Frederick Douglas Blvd & W 115th St_____10 meters

Frederick Douglas Blvd & W 116th St______9 meters

Frederick Douglas Blvd & W 118th St______8 meters

Frederick Douglas Blvd & W 120th St ______7 meters

Frederick Douglas Blvd & W 124th St______7 meters

Frederick Douglas Blvd & W 126th St______8 meters

Frederick Douglas Blvd & W 133rd St_______7 meters

Frederick Douglas Blvd & W 137th St_______7 meters

Frederick Douglas Blvd & W 145th St_______6 meters

Frederick Douglas Blvd & W 149 St_________5 meters

Frederick Douglas Blvd & W 153rd St_______4 meters

Frederick Douglas Blvd & Harlem River Dr.___1 meter