# city elevation and Denver Capitol Building **URL:** \ **Category:** Cecil's Columns/Staff Reports\ **Created:** [September 21, 2000, 8:52pm UTC](https://boards.straightdope.com/t/city-elevation-and-denver-capitol-building/34053 "2000-09-21T20:52:01Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Arnold\_Winkelried](https://avatars.discourse-cdn.com/v4/letter/a/3d9bf3/32.png) [@Arnold\_Winkelried](https://boards.straightdope.com/u/Arnold_Winkelried)\ **Post date:** [September 21, 2000, 8:52pm UTC](https://boards.straightdope.com/t/city-elevation-and-denver-capitol-building/34053/1 "2000-09-21T20:52:01Z")
Cecil’s column «[How is the city elevation shown on road signs and maps determined? (03-May-1996)](http://www.straightdope.com/classics/a960503b.html)», which says > [@](#): > > For example, Denver, the mile-high city, is listed in the World Almanac as having an elevation of 5,280 feet. But if you tap into the Geographic Names Information System maintained by the U.S. Geological Survey ( [http://www-nmd.usgs.gov/www/gnis](http://www-nmd.usgs.gov/www/gnis) ), you find Denver has subsided to just 5,260 feet. reminded me of my visit to Denver, where I saw the mile-high marker at the Capitol Building. [Colorado State Capitol Virtual Tour - Mile High Marker](http://www.archives.state.co.us/cap/mile.htm) How are altitudes determined that exactly? At the Colorado site you see that some students determined that the original mile marker was three steps too low. ---
**Author:** ![RM\_Mentock](https://avatars.discourse-cdn.com/v4/letter/r/e274bd/32.png) [@RM\_Mentock](https://boards.straightdope.com/u/RM_Mentock)\ **Post date:** [September 22, 2000, 2:48am UTC](https://boards.straightdope.com/t/city-elevation-and-denver-capitol-building/34053/2 "2000-09-22T02:48:21Z")
GPS allows very fine resolution now, especially since _selective availability_ has been turned off. But older surveying techniques were capable of high precision–they just weren’t as “easy” as GPS. A related question is, _what_ is the Denver capitol 5280 feet above? That would be the North American Datum–a best-fit ellipsoid that matches time-averaged sea-level and is extended mathematically to the interior of the continent. The datums are revised occasionally, and the current revision is moving to a world-wide reference datum. ---
**Author:** ![Wendolynne](https://avatars.discourse-cdn.com/v4/letter/w/848f3c/32.png) [@Wendolynne](https://boards.straightdope.com/u/Wendolynne)\ **Post date:** [September 22, 2000, 2:54am UTC](https://boards.straightdope.com/t/city-elevation-and-denver-capitol-building/34053/3 "2000-09-22T02:54:45Z")
I’m from a land-locked state … How much does “sea level” fluctuate from high tide to low tide? It seems we might be quibbling over 20 feet … ---
**Author:** ![RM\_Mentock](https://avatars.discourse-cdn.com/v4/letter/r/e274bd/32.png) [@RM\_Mentock](https://boards.straightdope.com/u/RM_Mentock)\ **Post date:** [September 22, 2000, 3:44am UTC](https://boards.straightdope.com/t/city-elevation-and-denver-capitol-building/34053/4 "2000-09-22T03:44:06Z")
Four feet or so–but sea-level is “time-averaged” to compensate for the variation. ---
**Author:** ![yabob](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yabob/32/2821_2.png) [@yabob](https://boards.straightdope.com/u/yabob)\ **Post date:** [September 22, 2000, 4:24am UTC](https://boards.straightdope.com/t/city-elevation-and-denver-capitol-building/34053/5 "2000-09-22T04:24:56Z")
Difference between high and low tide varies greatly with region, as well as with the lunar cycle. The Bay of Fundy, for instance has 50 foot tides: [http://www.scottwalking.com/quickfacts.html](http://www.scottwalking.com/quickfacts.html) San Francisco Bay’s largest difference between high and low tide is about 7 feet, IIRC. Significant since much of the bay is very shallow. Four feet is probably a typical range for a long, straight coastline. ---
**Author:** ![Jack\_Hannon](https://avatars.discourse-cdn.com/v4/letter/j/87869e/32.png) [@Jack\_Hannon](https://boards.straightdope.com/u/Jack_Hannon)\ **Post date:** [September 22, 2000, 8:00pm UTC](https://boards.straightdope.com/t/city-elevation-and-denver-capitol-building/34053/6 "2000-09-22T20:00:13Z")
I am reminded of my first trip out west. A passenger in the car looked at Bronco’s stadium and remarked, well it’s awfully tall, but no way that’s a mile high! Ah, NJ public schools… Jack [http://www.straightdope.com/classics/a960503b.html](http://www.straightdope.com/classics/a960503b.html) ---
**Author:** ![Arnold\_Winkelried](https://avatars.discourse-cdn.com/v4/letter/a/3d9bf3/32.png) [@Arnold\_Winkelried](https://boards.straightdope.com/u/Arnold_Winkelried)\ **Post date:** [September 22, 2000, 8:16pm UTC](https://boards.straightdope.com/t/city-elevation-and-denver-capitol-building/34053/7 "2000-09-22T20:16:35Z")
> [@](#): > > \*Originally posted by RM Mentock \* > But older surveying techniques were capable of high precision–they just weren’t as “easy” as GPS. I guess that was my question. What are these older surveying techniques? I imagine that it’s more involved than walking around with a barometer. ---
**Author:** ![Mr.Cynical](https://avatars.discourse-cdn.com/v4/letter/m/ee59a6/32.png) [@Mr.Cynical](https://boards.straightdope.com/u/Mr.Cynical)\ **Post date:** [September 22, 2000, 9:08pm UTC](https://boards.straightdope.com/t/city-elevation-and-denver-capitol-building/34053/8 "2000-09-22T21:08:23Z")
As a Denverite, I would recommend that you use the more recent measurement, the purple row of seats at Coors Field, for a standard. They sure seem to be higher than the steps, but it’s all relative. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [September 23, 2000, 3:13am UTC](https://boards.straightdope.com/t/city-elevation-and-denver-capitol-building/34053/9 "2000-09-23T03:13:29Z")
Well, you can determine the relative height of any two points within line of sight with a theadolite, a plumb bob, and the horizontal distance between the two points. Perhaps you just iterate this procedure from the location of your standard datum? ---
**Author:** ![RM\_Mentock](https://avatars.discourse-cdn.com/v4/letter/r/e274bd/32.png) [@RM\_Mentock](https://boards.straightdope.com/u/RM_Mentock)\ **Post date:** [September 23, 2000, 7:39pm UTC](https://boards.straightdope.com/t/city-elevation-and-denver-capitol-building/34053/10 "2000-09-23T19:39:19Z")
> [@](#): > > \*Originally posted by Arnold Winkelried \* > **I guess that was my question. What are these older surveying techniques? I imagine that it’s more involved than walking around with a barometer.** Do you want [theoretical](http://www.flatsurv.com/basic.htm), or [practical](http://corinth.sas.upenn.edu/surveying.html)? The construction of the roman viaducts depended upon being able to traverse long distances and know the exact rise and fall of the terrain. George Washington dragged a surveyor’s chain when he was younger, and Henry David Thoreau was compelled to include his survey observations of Walden Pond in his famous book. The world has been crisscrossed (or triangulated) many times over. Most expeditions are surveys, not just folks tramping through the mud. They established benchmarks of concrete and iron, and generations later they’re still in use. Mistakes get made of course. And some observations turn out to be paradoxical–which sometimes lead to new theories of the earth. When the mass of mountains turned out to _not_ deflect surveyors’ instruments as much as they would have thought, the theory of isostasy and the study of the earth’s interior was born. Maybe it is just incredible that people are capable of making exacting measurements over long distances? It is. My favorite example of this is the precession of Mercury. But that’s astronomy.