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The following dataset, known as "Active Benchmarks," is provided to facilitate the identification of City-managed standard benchmarks. Standard benchmarks are for public and private use in establishing a point in space. This dataset was last updated February 2011. Click here to view map.
Description: This dataset provides "Active Benchmarks," which facilitate the identification of City-managed standard benchmarks. Standard benchmarks establish a point in space, and are used by surveyors in measuring site elevations, or as a starting point for surveys. To view map, go to https://data.cityofchicago.org/Buildings/Elevation-Benchmarks-Map/kmt9-pg57 or for PDF map click here.
The dataset includes the following attributes for each benchmark: number, northing, easting, elevation, location description, mark description, year benchmark elevation was fixed, book number, and comments.
Note: The Benchmarks are referenced to the Chicago City Datum = 0.00, (CCD = 579.88 feet above mean tide New York).
The City of Chicago Department of Water Management’s [Topographic Benchmark] is the source of the benchmark information contained in this online database. The information contained in the index card system was compiled by scanning the original cards, then transcribing some of this information to prepare a table and map. Over time, the DWM will contract services to field verify the data and update the index card system and this online database.
Data Owner: Water Management
Last Updated: February 2011