CSRC and the PRC
Posted: Wed Sep 05, 2012 10:48 am
CSRC and the Revised Public Resources Code
Now that I have a little time on my hands I thought that I would put down for the record the reasons why and how it came about the revisions to the PRC relative to geodetic datums in 2005.
About 15 years or so ago the funding for NGS began to diminish. So much so that they were not able to meet all of the geospatial needs of California with our ever present crustal motion and subsidence issues. So, the CSRC came about to fill this void. Particularly with respect to height modernization and other issues.
In 2004, Dr. Bock and Greg Helmer among others came up with the idea to revise the Public Resources Code to add a chapter on the California Spatial Reference Network (CSRN), California Orthometric Heights, and California Geodetic Coordinates while revising the existing California Coordinate System chapter.
A group was assembled that included Dick Davis, Greg Helmer, Mike McGee, Marti Ikehara, Larry Fenske, and myself along with some corresponding members to begin the task. The main person doing all of the heavy lifting in the beginning was Larry. He put pen to paper and was in charge of compiling all of the subsequent revisions. I was put in charge of facilitating and coordinating the meetings and keeping track of the minutes, etc. Along the way, Larry and I began to communicate at length and to work on the revisions together that were brought forward for the rest to review. It was an arduous task but we finally achieved a consensus and in 2005 the revision were sent to CLSA legislative committee (I was chair) where they carried it forward to the legislature and the revisions to the PRC were chaptered to include a chapter on the CSRN, COH, CGC, and revision to CCS.
So what? What does it mean? How does it work? What was the thinking behind the changes?
The CSRN is a subset of the NSRS as well as an extension of it. The CSRN is the backbone geodetic network of stations in California that form the basis for our geodetic datums. Stations a part of the CSRN have to be published by either NGS or the CSRC. This is where the CSRC has been placed into law as the preeminent organization in California for maintaining our backbone geodetic network.
http://www.leginfo.ca.gov/cgi-bin/displ ... =8850-8861
So, geospatial values produced under the requirements of the other chapters (CCS, COH, and CGC) all have to be either tied to the CSRN or to a station not published by NGS or the CSRC but meet the requirements for inclusion in the CSRN. In all practicality all stations will have a connection to the CSRN. This makes CSRC’s position very important in the geospatial world.
http://www.leginfo.ca.gov/cgi-bin/displ ... =8801-8819
http://www.leginfo.ca.gov/cgi-bin/displ ... =8870-8880
http://www.leginfo.ca.gov/cgi-bin/displ ... =8890-8902
What we then did in the CCS chapter (and emulated in the COH and CGC Chapters) is remove the requirement for two connections to a high order station and reduced it to one. Why? Because we wanted to assure that anyone that wanted to use a legally defined horizontal and/or vertical datum could access them readily from one station and thereby create geospatial values consistent with any other entity across the state. This would include GIS, planning, etc. along with Land Surveying. However, we also put in sections that described what needs to happen if you claim accuracy. (See the code sections). I.e. anybody can produce CCS, COH, and CGC values; however, if you claim an accuracy then a whole slew of requirements kick in to support those claims.
Can anybody claim accuracy? The answer is No. At the same time as the PRC revisions were taking place. The CLSA legislative committee also revised the LSACT in the Business and Professions Code. Specifically Section 8726, which defines the tasks that can only legally be done by a licensed land surveyor in California. The section that we added was 8726 (n) “(n) Renders a statement regarding the accuracy of maps or measured survey data.â€
http://www.leginfo.ca.gov/cgi-bin/waisg ... n=retrieve
So, the code sections together provide the priority of the CSRC relative to the backbone geodetic network; anyone can access and produce a CCS, COH and CGC value which encourages consistency in databases, GIS, etc.; if an accuracy statement is made it has to be rigorously supported; and finally, any statement of accuracy on the produced CCS, COH, CGC geospatial positions (or any other map or survey data) has to be stated by someone legally licensed to practice Land Surveying in the state of California.
Now that I have a little time on my hands I thought that I would put down for the record the reasons why and how it came about the revisions to the PRC relative to geodetic datums in 2005.
About 15 years or so ago the funding for NGS began to diminish. So much so that they were not able to meet all of the geospatial needs of California with our ever present crustal motion and subsidence issues. So, the CSRC came about to fill this void. Particularly with respect to height modernization and other issues.
In 2004, Dr. Bock and Greg Helmer among others came up with the idea to revise the Public Resources Code to add a chapter on the California Spatial Reference Network (CSRN), California Orthometric Heights, and California Geodetic Coordinates while revising the existing California Coordinate System chapter.
A group was assembled that included Dick Davis, Greg Helmer, Mike McGee, Marti Ikehara, Larry Fenske, and myself along with some corresponding members to begin the task. The main person doing all of the heavy lifting in the beginning was Larry. He put pen to paper and was in charge of compiling all of the subsequent revisions. I was put in charge of facilitating and coordinating the meetings and keeping track of the minutes, etc. Along the way, Larry and I began to communicate at length and to work on the revisions together that were brought forward for the rest to review. It was an arduous task but we finally achieved a consensus and in 2005 the revision were sent to CLSA legislative committee (I was chair) where they carried it forward to the legislature and the revisions to the PRC were chaptered to include a chapter on the CSRN, COH, CGC, and revision to CCS.
So what? What does it mean? How does it work? What was the thinking behind the changes?
The CSRN is a subset of the NSRS as well as an extension of it. The CSRN is the backbone geodetic network of stations in California that form the basis for our geodetic datums. Stations a part of the CSRN have to be published by either NGS or the CSRC. This is where the CSRC has been placed into law as the preeminent organization in California for maintaining our backbone geodetic network.
http://www.leginfo.ca.gov/cgi-bin/displ ... =8850-8861
So, geospatial values produced under the requirements of the other chapters (CCS, COH, and CGC) all have to be either tied to the CSRN or to a station not published by NGS or the CSRC but meet the requirements for inclusion in the CSRN. In all practicality all stations will have a connection to the CSRN. This makes CSRC’s position very important in the geospatial world.
http://www.leginfo.ca.gov/cgi-bin/displ ... =8801-8819
http://www.leginfo.ca.gov/cgi-bin/displ ... =8870-8880
http://www.leginfo.ca.gov/cgi-bin/displ ... =8890-8902
What we then did in the CCS chapter (and emulated in the COH and CGC Chapters) is remove the requirement for two connections to a high order station and reduced it to one. Why? Because we wanted to assure that anyone that wanted to use a legally defined horizontal and/or vertical datum could access them readily from one station and thereby create geospatial values consistent with any other entity across the state. This would include GIS, planning, etc. along with Land Surveying. However, we also put in sections that described what needs to happen if you claim accuracy. (See the code sections). I.e. anybody can produce CCS, COH, and CGC values; however, if you claim an accuracy then a whole slew of requirements kick in to support those claims.
Can anybody claim accuracy? The answer is No. At the same time as the PRC revisions were taking place. The CLSA legislative committee also revised the LSACT in the Business and Professions Code. Specifically Section 8726, which defines the tasks that can only legally be done by a licensed land surveyor in California. The section that we added was 8726 (n) “(n) Renders a statement regarding the accuracy of maps or measured survey data.â€
http://www.leginfo.ca.gov/cgi-bin/waisg ... n=retrieve
So, the code sections together provide the priority of the CSRC relative to the backbone geodetic network; anyone can access and produce a CCS, COH and CGC value which encourages consistency in databases, GIS, etc.; if an accuracy statement is made it has to be rigorously supported; and finally, any statement of accuracy on the produced CCS, COH, CGC geospatial positions (or any other map or survey data) has to be stated by someone legally licensed to practice Land Surveying in the state of California.