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Central Valley Chapter
California Land Surveyors Association

Promoting the professional practice of land surveying in the California Central Valley.
Serving the greater Merced, Stanislaus and San Joaquin County Area."

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Modesto Calibration Baseline Rehabilitation Project

Land Surveyors can use a set of surveyed monuments located along a baseline to check the electronic distance meters on their measuring equipment. (Electronic distance meters are typically included on total station instruments, which measure both angles and distances). These monuments are certified by the National Geodetic Survey (NGS) and are known as “calibration baselines”.

There is an existing calibration baseline in Modesto, California. The Central Valley Chapter of the California Land Surveyors Association has completed the rehabilitation this calibration baseline, which fell into disuse.

The initial site inspection was completed in the Spring of 2010. The measurement of the baseline by volunteers from the CLSA California Central Valley Chapter with the assistance of NGS was completed in the Summer of 2010.

Project Updates

  • Baseline Measurement Complete: The official publication of the baseline monument distances is complete. You will find the published data for our Modesto baseline in the NGS datasheet listing data for all California baselines. The data for just the Modesto baseline is also listed in the PDF linked to in the NGS Results section below.
  • Baseline Measurement Complete: The measurement of the baseline monuments was completed by CLSA Central Valley Chapter volunteers and NGS. The baseline measurement took two (2) long days of field work. Staff from the City of Manteca, City of Modesto, Stanislaus County, Northstar Engineer, and KSN spent portions or all of the two (2) days assisting at the baselines. (The chapter sent letters of appreciation and thanks to each organization that contributed trucks, equipment, and man hours to the baseline measurement.) You can view photos of the baseline measurement below.
  • Site Inspection Complete: Keith Spencer and Landon Blake performed a site inspection at the CBL site in Modesto. They recovered and took photographs of all four (4) CBL monuments. The photographs, written description of the monument locations, and monument coordinates provided by the Stanislaus County Surveyor Department were all delivered to Marti Ikehara, the NGS Advisor for California.
  • CBL Measurement Date Scheduled: Monday, August 23 and Tuesday, August 24 are the dates tentatively schedule for measurement of the CBL monuments with the equipment from NGS. This means leveling work at the baseline will need to be performed at the end of June or beginning of August.

Site Inspection Data

You can download the photos, written descriptions, and approximate monument coordinates for the Modesto Baseline.

NGS Results

You can download the Calibration Results for the Modesto Baseline.

Site Inspection Photos

image 1 image 2 image 3
Monument #1 Monument #1 Monument #2
image 4 image 5 image 6
Monument #2 Monument #3 Monument #3
image 7 image 8
Monument #4 Monument #4

Baseline Measurement Photos

You can download high resolution photos taken during the measurement of the Modesto Baseline.

image 1 image 2 image 3
Larry Fontana (Stanislaus County) prepares to take a distance measurement. Chris Martin (KSN) level a prism over one of the baseline monuments. A veiw of the calibration baseline site looking east early on the second work day.
image 4 image 5 image 6
Chris Martin (KSN) verifies the tribrach is over the punch mark on one of the calibration baseline monuments. The prism set-up over Monument #2. Chris Martin (KSN) watches over the prism and metrological instruments at Monument #2.
image 7 image 8 image 9
Lary Fontana (Stanislaus County) and Alfredo Mijango verify the tribrach is over the punch mark at Monument #3. A veiw of the calibration baseline site looking east. A veiw of the calibration baseline site looking west.
image 10 image 11 image 12
Lary Fontana (Stanislaus County) verifies the tribrach is over the punch mark at Monument #3. Chris Martin (KSN) measures a distance from Monument #1. The team poses for a group photo at Monument #4 at the end of the second work day.
image 13
The team poses for a group photo at Monument #4 at the end of the second work day.

Chapter News:

CLSA Sacramento Chapter Presents:

Dennis Mouland Seminar, September 15 and 16
Space is limited, reserve your slot today!

(see attached flyer)


Continous GPS Stations

A message from Rob McMillan:

Below are excerpts of emails from Unavco's Chris Walls and Sharon Williams of the National Science Foundation. Please read and respond to the survey at the link below. This is particularly critical if you perform any of the following:

  • Static GPS surveys
  • RTK GPS surveys using a virtual reference network (CSDS, Leica, Topcon, AZGPS, OCRTN, CVSRN, etc.)
  • Surveys tied to NGS control (the National Spatial Reference System (NSRS))
  • Surveys tied to the California Spatial Reference System (CSRS)
  • Surveys in state plane coordinates
  • Surveys tied to NAVD88 datum
  • Surveys tied to tidal datums
  • Surveys in areas of tectonic activity
  • Surveys using HTDP
  • Monitoring surveys (structural monitoring, dam deformation, etc)

This infrastructure also can support advancements in earthquake early warning, precision agriculture, automated machine guidance, autonomous vehicles, positive train control, and more.

Dear Colleagues, The future performance, capabilities, and station count of the Plate Boundary Observatory is at a crossroads. UNAVCO is currently developing budgets and plans for operating the network beyond 2018 including scenarios of reduced network density. If you rely on UNAVCO-provided PBO data then I recommend you make it clear what the uses are, what the regions of interest are, and even specific stations or data type (i.e. 1Hz, 5Hz, 15s, Met, real-time, seismic etc...). Please forward to collaborators who will miss the data if resources are not available.
Regards,
Chris

PS - the survey will take 5-10 minutes, contrary to what is described below. Thank you for your participation.

Dear UNAVCO Users,
At the request of the National Science Foundation (NSF), the Science and Technology Policy Institute (STPI) has been asked to solicit feedback on the activities, products, and services provided by UNAVCO. NSF, UNAVCO, and STPI would all appreciate your time and response to this survey. The survey itself should take between 20-30 minutes. Your participation is completely voluntary. Your responses will not be shared individually and will not impact your relationship with NSF or UNAVCO. STPI is an independent, Federally Funded Research and Development Center and will be collecting and analyzing all responses. If you are a UNAVCO member or RESESS participant and have received a previous invitation to this survey, please disregard this email. We apologize for multiple survey invitations, but we are hoping for feedback from as many individuals as possible. Please feel free to contact Sharon Williams at STPI (swilliam@ida.org; 202-419-5411) or Russell Kelz (rkelz@nsf.gov; 703-292-4747) at NSF if you have any questions or concerns.

Survey link:


Next Scouting Merit Badge Session

Will be August 27th


Central Valley Chapter Awarded Chapter of the Year at 2016 Convention


Our Newsletter "The Prism" July 2016

California Surveyor: "Summer 2016"

BPELSG News:

BPELSG Example CBT Examination Questions:

BPELSG Bulletin: Spring 2016


New in the Library:

Tuolumne County - Updated Record Maps and Corner Records, added Mineral Surveys
San Joaquin County - added Filed Map Footprints
updated February 2016 Guide to the Preparation of Maps
updated ROS, PM, M&P, Corner Records
Madera County - updated Record maps
Santa Clara County - updated Record maps and Corner Records
Sacramento County - added link to Geographical Map Index
Fresno County - updated record maps
Stanislaus County - updated record maps


CLSA Chapter Website of the Year - 2012-2014