2014-01-26

Local Benchmark Lists

There are many local agencies in my area (and around the world actually) which have published lists and databases of their local benchmark loops.  However, the term "published" means different things to different agencies and jurisdictions.  It is often defined by the scope of the benchmark system, and the budget that the agency has to maintain their database, regardless of how complex it may be.  As such, some agencies publish their benchmark database online with an interactive GIS.  Other agencies may only keep a handwritten list and "publishing" said list is an act involving a Xerox machine.  Most agencies are somewhere in between.

For example, the City of Fresno has a searchable, online database, that lists the benchmarks by street.  It is not GIS based, but it's easy to use and plenty functional for those who use it.  The County of Fresno, on the other hand, maintains its database using an internal Access DataBase file.  It is not published online, but they will give copies of the most current database file to those who ask.  Most smaller communities just keep short lists and send them out to those who request them.

I've recently added some of the benchmark lists I have, and routinely use, to this blog in the form of a page titled "BMark Lists".  Look for the tab above, or click HERE.

2014-01-04

GU1005 - "G1040 1959"

I wasn't completely prepared to find this mark when I did.  It was late in the day, and I'd spent most of it burning a tank of fuel on a motorcycle ride.  I'd been through this intersection before, although it's not a usual route.  For some reason, I'd never seen this mark even though it is promently placed on the canal headwall, as many are throughout this part of the Valley.  I found my GPSr with dead batteries so I wasn't able to take a new set of coordinates. - KN
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Published details for Benchmark: GU1005
N 36° 36.217
W 120° 02.600 (NAD 83)
Altitude: 200.8
Coordinates may not be exact. Altitude is VERTCON and location is SCALED.

Location: In FRESNO county, CA View Original Datasheet
Designation: G 1040
Marker Type: bench mark disk
Setting: light structures
Stability: Mark of questionable or unknown stability.

Documented History (by the NGS)
1/1/1959 by CGS (MONUMENTED)
DESCRIBED BY COAST AND GEODETIC SURVEY 1959 7.9 MI W FROM RAISIN CITY. 7.9 MILES WEST ALONG MANNING AVENUE FROM THE T JUNCTION OF ORMUS AVENUE AT RAISIN CITY, 8.15 MILES EAST OF SAN JOAQUIN, AT THE INTERSECTION OF MC MULLIN GRADE, AT THE CROSSING OF AN IRRIGATION CANAL, IN TOP OF THE EAST END OF THE NORTHEAST CONCRETE HEAD WALL OF A 72-INCH ASKEW CONCRETE PIPE CULVERT UNDER THE AVENUE, 30 FEET NORTH OF THE CENTER LINE OF THE AVENUE, 142 FEET NORTHWEST OF THE CENTER LINE OF MC MULLIN GRADE, AND ABOUT 1/2 FOOT HIGHER THAN THE AVENUE.

Found details for Benchmark: GU1005
Found at 16:30, 04 Jan. 2014 as described and in good condition. Published description is adequate. New coordinates were not taken.

GU1005 "G1040 1959" - Benchmark detail.
GU1005 "G1040 1959" - Benchmark set in a canal headwall.
GU1005 "G1040 1959" - Benchmark set in a canal headwall.  View north.