Geodetic Survey Monuments and their attachments last verified to be correct 1/22/22.This product is for informational purposes and may not have been prepared for or be suitable for legal, engineering or surveying purposes. It does not represent an on-the-ground survey and represents only the approximate relative location of property boundaries. This disclaimer is required per Texas House Bill 1147.

Purpose and Use: This dataset was created to help with locating the GPS Benchmarks in and around San Marcos.Data Source: Data in this GPS Survey Benchmarks layer is created and maintained by the City of San Marcos, Texas, Geographic Information Systems (GIS) department.Contact: Geographic Information Systems (GIS): gisinfo@sanmarcostx.govUpdate Frequency: As needed.Jurisdiction: City of San Marcos.Fields:OBJECTID: System-generated unique identifier for each record within the feature class. SOURCE: Organization that provided the data. NAME: Name associated to the GPS Monument by the number at which it was recorded. INSTALLDATE: Date of installation for the real-world feature represented in the feature class. ELEVATION: Elevation recorded during monument placement, above sea level. XCOORDINATE: The horizontal value in a pair of coordinates: how far along the point is. The X Coordinate is always written first in an ordered pair. YCOORDINATE: The vertical value in a pair of coordinates. How far up or down the point is. The Y Coordinate is always written second in an ordered pair. DISTANCE1: This is the footage distance from the described location in 'Distance1Description' field. DISTANCE2: This is the footage distance from the described location in 'Distance2Description' field. DISTANCE3: This is the footage distance from the described location in 'Distance3Description' field. AZIMUTH: An angular measurement in a spherical coordinate system. The vector from an observer to a point of interest is projected perpendicularly onto a reference plane; the angle between the projected vector and a reference vector on the reference plane is called the azimuth. BEARING: The actual (corrected) compass direction of the forward course of the aircraft. In land navigation, a bearing is the angle between a line connecting two points and a north-south, or meridian. DISTANCE1DESCRIPTION: This is the described location from which the distance is collected as a total of 3 location points. DISTANCE2DESCRIPTION: This is the described location from which the distance is collected as a total of 3 location points. DISTANCE3DESCRIPTION: This is the described location from which the distance is collected as a total of 3 location points. ROUTEDESCRIPTION: General description for where the marker is located in reference to known locations. MARKERCATEGORY: The way in which the marker is placed for GPS such as being placed in an aluminum disk set in concrete which is found physically in the ground. MEDIALINK: URL for a website related to the record. PRODUCTIONNOTES: Technical notes from GIS personnel. DESCRIPTION: Statement illustrating the feature. CREATEDBY: Name of the person logged into the system that GIS automatically stamps as the original creator. CREATEDDATE: Date/time stamp from the moment the GIS record was created. MODIFIEDBY: Name of the person logged into the system that GIS automatically stamps as the feature is modified. MODIFIEDDATE: Date/time stamp from the last moment the GIS record was changed. SHAPE: System-generated geometry type of the feature. Shape.len: System-generated length of the feature. GlobalID: System-generated unique identifier for each record that is required in replicated geodatabases.

Map showing benchmark locations within the City of Sugar Land.

This is a point data set representing monumented vertical geodetic survey control points (a.k.a. elevation benchmarks) established by the City of Boise. A benchmark is a physical marker, monument, or demarcation established by a surveyor for horizontal and/or vertical measurement control. This data set only contains benchmarks established by the City of Boise that are based on the North American Vertical Datum of 1988 (NAVD 88); benchmarks established under other vertical datums are not included. The elevation values in this data set are based on the vertical control from the National Geodetic Survey (NGS), the U. S. Geological Survey (USGS), and some state owned vertical control. The horizontal location is obtained by Global Positioning System (GPS) data collection of the surveyed benchmark. Attribute data including elevation, is transcribed from surveying field books supplied by Boise City Public Works survey personnel. Data Attributes:MARK TYPE: ALCAP - Aluminum Cap, BRASSCAP - Brass Cap, CHISELSQ - physically carved square, PK - A steel masonry nail manufactured by Parker Kaelon (PK nail), OTHER - Any other survey marker type.LOCATION: Nearest street or cross streets to the benchmark.ELEVATION: The vertical elevation in feet above sea level as established from survey calculations based on the 1988 NAVD Datum.GPS DATE: Date the benchmark was captured by GPS.COMMENTS: Pertinent notes on general description and location of the benchmark.BOOK: The City of Boise Public Works surveying field book number the benchmark was established under.PAGE: The City of Boise Public Works surveying field book page the benchmark was established under.The data set is maintained by the Boise City Public Works GIS staff. The data is updated continuously. It is current to the date it was published.For more information, please visit Ada County Control Information or City of Boise Public Works.

This data is a subset of the original National Geodetic Survey (NGS) data that includes only locations within Volusia County, FL.This data contains a set of geodetic control stations maintained by the National Geodetic Survey. Each geodetic control station in this dataset has either a precise Latitude/Longitude used for horizontal control or a precise Orthometric Height used for vertical control, or both.The National Geodetic Survey (NGS) serves as the Nation's depository for geodetic data. The NGS distributes geodetic data worldwide to a variety of users. These geodetic data include the final results of geodetic surveys, software programs to format, compute, verify, and adjust original survey observations or to convert values from one geodetic datum to another, and publications that describe how to obtain and use Geodetic Data products and services.Horizontal control stations (those with precise Latitude, Longitude) were established in accordance with FGDC publications "Standards and Specifications for Geodetic Accuracy Standards" and "Geometric Geodetic Accuracy Standards and Specifications for Using GPS Relative Positioning Techniques" The final Latitude, Longitude of these stations were determined by a least squares adjustments of the horizontal observations. Horizontal control station have Latitude, Longitudes displayed to 5 places and are identified by attribute POS_SRCE = 'ADJUSTED'Lesser quality Latitude, Longitudes may also be preset in the dataset. These are identified by a POS_SRCE attributes HD_HELD1, HD_HELD2, or SCALED. These lesser quality positions are described at: https://www.ngs.noaa.gov/cgi-bin/ds_lookup.prl?Item=SCALEDVertical control stations (those with precise Orthometric Heights) were established in accordance with FGDC publications "Standards and Specifications for Geodetic Accuracy Standards" The final Orthometric Height of these stations were in most cases determined by a least squares adjustments of the vertical observations but in some cases may have been keyed from old survey documents. Vertical control stations have Orthometric Heights displayed to 2 or 3 places and are identified by attribute ELEV_SRCE of ADJUSTED, ADJ UNCH, POSTED,READJUST,N HEIGHT,RESET,COMPUTEDLesser quality Orthometric Heights may also be preset in the dataset. These are identified by a ELEV_SRCE attributes GPS_OBS, VERT_ANG, H_LEVEL, VERTCON, SCALED. These lesser quality orthometric heights are described at: https://www.ngs.noaa.gov/cgi-bin/ds_lookup.prl?Item=SCALEDIMPORTANT - Control stations do not always have both precise Latitude, Longitude AND precise Orthometric Height. A horizontal control station may have a orthometric height associated with it which is of non geodetic quality. These types of heights are displayed to 0, 1, or 2 decimal places. Worst case being off by +/- 1 meter. LIKEWISE - A Vertical control station may have a Latitude, Longitude associated with it which is of non geodetic quality. These types of Latitude, Longitudes are displayed to 0, 1 or 2 decimal places. Worst case being off by +/- 180 meter. Refer to https://www.ngs.noaa.gov/cgi-bin/ds_lookup.prl?Item=SCALED for a description of the various type of methods used in determining the Latitude, Longitude, and Orthometric Height.Attribute POS_CHECK and ELEV_CHECK indicate whether or not an observational check was made to the position and/or orthometric height. Care should be taken when using "No Check" coordinates.If attribute ELEV_SRCE = 'VERTCON' then the Orthometric Height was determined by applying NGS program VERTCON to an Old NGVD 29 height. In most areas VERTCON gives results to +/- 2 cm. See https://www.ngs.noaa.gov/TOOLS/Vertcon/vertcon.html for a more detailed explanation of VERTCON accuracy.Ellipsoid Heights are also present in the dataset. The ellipsoid heights consist of those determined using a precise geoid model, which are displayed to 2 decimal places and are considered good to +/- .005 meters, and those displayed to 1 decimal place and are considered only good to +/- .5 metersQuantitative_Attribute_Accuracy_Assessment:Attribute_Accuracy_Value: 95 percent confidence level for geodetic quality data.Attribute_Accuracy_Explanation:Geodetic Data are continuously being processed; their standards and specifications are being reviewed for next publication release. "Standards and Specifications for Geodetic Control Networks", 1984 and "Geometric Geodetic Accuracy Standards and Specifications for Using GPS Relative Positioning Techniques," FGCS (formally FGCC) publication version 5.0 1989, are most current published documents.Logical_Consistency_Report:FGCS sponsored testing in cooperation with equipment manufacturers and National Institutes of Standards and Technology, Gaithersburg, MD 20850Completeness_Report:This dataset DOES NOT include destroyed marks. All other non-publishable marks are NOT included. Non-publishable criteria is available at https://www.ngs.noaa.gov/cgi-bin/craigs_lib.prl?HELP_NONPUB=1

In 2008, DWR developed a series of survey monuments in the Sacramento Valley to create a subsidence monitoring network. The network encompasses all or part of 11 counties, from Shasta County at the north end of the valley to Solano and Sacramento counties in the south. It includes over 300 benchmarks with an average spacing of 4.3 miles (7 kilometers). During the spring/summer of 2008, DWR along with 25 local, State, and federal partners performed an initial GPS survey of the network to establish a baseline measurement to compare against future surveys. The initial survey was done using National Geodetic Survey standards. DWR resurveyed the monument network in 2017 with assistance from 19 State, county, and local agencies, and a private entity. The methodology and equipment used was similar to the 2008 survey. Analysis of the results was done to depict the change in height at each monument from 2008 to 2017. The Arbuckle area (Colusa County) showed the most subsidence with a maximum change of -2.14 feet (ft.). Surrounding stations and InSAR data confirm this result with changes ranging from -0.49 to -1.00 ft. In eastern Yolo County (Zamora to Davis), the largest spatial extent of station declines was observed with several benchmarks showing changes between -0.3 and -1.1 ft. In Glenn County (Artois and Orland area), three stations, ARTO, K852, and AGUI showed changes of -0.59 ft., -0.46 ft., and -0.44 ft., respectively. An area on the south side of the Sutter Buttes showed changes ranging from -0.19 to -0.36 ft. The remainder of the valley shows little change overall. During the time of the 2017 survey, groundwater levels in the Sacramento Valley were recovering from the severe drought of 2012-16. During the drought, groundwater levels hit historic lows in most wells in the Sacramento Valley with maximum decreases in Glenn and Colusa Counties of 58 ft. and 43 ft., respectively, compared to 2011 pre-drought conditions. During the survey field work in 2017, groundwater levels had recovered about 7 ft. on average since 2015. The period between the two surveys was nine years, and it was not possible to determine when during that time frame the changes shown took place. However, it is likely that the subsidence occurred during the drought in 2012-16 when groundwater levels in many wells reached historic lows due to increased groundwater pumping. To better bracket when changes occur, surveys at a more frequent interval (3-5 years), are recommended. Integrating groundbased subsidence monitoring such as continuous GPS sites and extensometers and remote sensing data, such as InSAR, into the subsidence monitoring network is also recommended.

Times of data collection at the sites where benchmarks (X) were measured and GPS mobile stations were installed for field campaigns (●).

Selection of daily distance variations between two pairs of GPS benchmarks (EMGL-EMAL and EMEG-ESLN) located in the western flank of Mt. Etna during 2002-2021. (Format: two GPS daily distance variations separated by comma in meters)

The authors acknowledge the Technicians and Technologists of the INGV - Osservatorio Etneo (GPS Permanent Network) for enabling and improving the acquisition of raw GNSS data. We are grateful to F. Cannavò that provided distance daily variations between two pairs of GPS benchmarks during the time periods when the solution is not available in Literature.

The Virginia Coast Reserve Long-term Ecological Research project, in association with the Virginia Marine Resources Commission, conducted an intensive GPS survey during February 1992. A second GPS survey was conducted in August 1994 to add supplemental GPS monuments. Most monuments consist of stainless steel pipes driven to refusal and topped with a bolt with a point imprinted on it. Others may consist of existing markers or cultural features. Elevations refer to the monument, not the surrounding ground surface. All data were processed by the VCR/LTER. Several caveats must be applied to use of this survey network: 1. These are preliminary results and are subject to change as the network is revised. 2. This network is designed for research purposes only, the data are not suitable for legal uses of survey data. 3. The network includes several US Government benchmarks, but except for the VCR1 monument recently resurveyed and "fixed" by the National Geodetic Survey (see below), the coordinates for those benchmarks have not been adjusted to agree with blue-book values for those benchmarks. 4. Elevations are based on mean sea-level (NAVD88) for a single point (VCR1). No geoid corrections have been applied to any other point. *** Update: MINOR coordinate shifts resulting from NGS adjustment of the VCR1 monument's estimated lat/lon following the NAD83 (Va) HARN adjustment of 2011 have been calculated (0.017 m S, 0.001 m W), but not otherwise applied to the data. A shapefile of the VCR GPS network based on the original coordinates has also been included.

This data is provided as a complimentary service and is intended to be used for surveying, engineering, and city-wide planning. The information contained was mapped by the City of Springfield through differential leveling methods. This elevation data was collected at various times in the past several decades, and was recently verified for accuracy in the Summer of 2010. To verify accuracy, the existing differential leveled data was shot with GPS and benchmarks found to be errant were re-leveled by differential methods.

Values in parentheses are standard deviations for benchmarks and standard errors for the data of campaign and continuous GPS.

GPS Monument Data features define survey information. These features are compiled from locations designated by the City of Edmond for accurate survey reference points. The monument data for the City of Edmond was originally produced by a highly accurate survey network of points throughout the City in 1995 and 1996. The goal of these GPS Monument Specifications is to maintain a high accuracy coordinate network for the City of Edmond. The monuments are used to maintain a high accuracy coordinate network in the City of Edmond. The GPS monument shall be constructed and set according to the City of Edmond GPS Monument Construction Standard. Every monument shall have a City of Edmond provided bronze marker stamped with a unique station number. Every effort should be made to place monuments in positions of extreme protection. Also locations that are accessible, safe and "GPSable" will be sought. Input from the City of Edmond is required before finalizing the position of GPS monuments. Following acceptance of monument construction, the center point of the monument shall be surveyed by a professional land surveyor registered with the State of Oklahoma for professional survey services to determine the actual positional coordinates of the monument. Coordinate data will be in NAD-83 format insuring compatibility with the new Oklahoma High Accuracy Reference Network. Elevation datum will be Mean Sea Level to insure accurate reference to local existent control, existing City of Edmond GPS monumentation and United States Geological Survey (USGS) benchmark data. Coordinates will be recorded in both Latitude and Longitude (degrees, minutes, seconds to the 4 significant digit) and State Plane US. Survey Feet. The minimum positional accuracy of GPS Monuments will be within 2cm. The accuracy of the GPS monument will be checked by the City of Edmond within one month of the monument being placed and surveyed.The City of Edmond makes every effort to produce and publish the most accurate information possible. While we are constantly updating our database and services, we cannot guarantee 100 percent accuracy and disclaim any responsibility for the accuracy of this data.

This 2' geoid height grid for the conterminous United States is the GEOID96 model. The computation used about 1.8 million terrestrial and marine gravity data held in the National Geodetic Survey gravity data base in July 1996. These data were augmented by gravity data contributions from NGA (former National Imagery and Mapping Agency (former Defence Mapping Agency)). By means of a Fast Fourier Transform (FFT) technique, high frequency corrections were made to an underlying EGM96 geopotential model through a remove, compute, and restore process. The gravity values are based on the International Gravity Standardization Net 1971 (IGSN71). The geoid heights are referred to the Geodetic Reference System 1980 (GRS80) ellipsoid. GEOID96 incorporates the reference system relationship between NAD 83(86) and ITRF94(1996.0), the datum offset of NAVD 88, and the contributions from 2951 GPS on leveled benchmarks. Additional information is available at http://www.ngs.noaa.gov/GEOID/geoid.htmlWe are particularly grateful to NGA (former National Imagery and Mapping Agency) for their assistance and their data contributions.

The database is a set of entities and attributes as referenced to individual geographic locations, hereafter referred to as "Point". Each individual Point has a location relative to all other points in the database as referenced to a coordinate grid. The relative location of the points as represented in this database correspond to the physical or determined locations of Survey Control Monumentation.

This dataset contains a bundle of 5 mass market receiver (ublox Neo M8T) and three geodetic graded receiver (Leica GNSS1200+GNSS, Septentrio PolaRx 5TR, Javad Delta TRE_G3T) combined in a zero baseline. The dataset captures 7 days of measurements with carrier phase, code phase, Doppler, carrier-to-noise ratio (C/N0) for GPS/GLONASS C/A code on frequency L1 for the mass market receiver and GPS/GLONASS/GALILEO L1/L2/L5 for geodetic receiver. All geodetic receiver were feeded by external rubidium clock (SRS FS725 Benchmark).

This 2' surface deflection of the vertical grid for the conterminous United States is the DEFLEC96 model. The computationused about 1.8 million terrestrial and marine gravity data held in the National Geodetic Survey gravity data base in July 1996. These data were augmented by gravity data contributions from NGA (former National Imagery and Mapping Agency (former Defence Mapping Agency)). The deflections were obtained by numerical differentiation of cubic spline models along the meridians of the GEOID96 grid. The gravity values are based on theInternational Gravity Standardization Net 1971 (IGSN71). The deflections are referred to the Geodetic Reference System 1980 (GRS80) ellipsoidal normals. The deflections of the vertical incorporate the reference system relationship between NAD 83(86) and ITRF94(1996.0), the datum offset of NAVD 88, and thecontributions from 2951 GPS on leveled benchmarks. The curvature of the plumb line correction has been applied. http://www.ngs.noaa.gov/DEFLEC/deflec.html We are particularly grateful to NGA (former National Imagery and Mapping Agency) for their assistance and their data contributions.

Error statistics of the accuracy assessment vs. GPS benchmarks.

A 4D microgravity survey began in early 2019 in order to benchmark surface and subsurface elevations prior to Phase 3 drilling and stimulation campaigns. Microgravity stations are collocated with GPS deformation benchmarks and use the same location survey data. Surveys are undertaken on a quarterly basis. The focus of current activities is comparative analysis of GPS survey results and InSAR analysis (see GDR Submission 1251) to check seasonal variance and to evaluate possible changes in the groundwater elevation. The attached zip file contains a text file and an Excel spreadsheet containing Utah FORGE Phase 3 processed "final" microgravity data through time. The data are identical in both files. The spreadsheet is only supplied for convenience. There is also a ReadMe.txt file that describes the field headings.

This dataset provides (X, Y, Z) coordinate data for three distinct test sites, supporting the evaluation of digital terrain modeling methods. Alemdar-1 contains NetCAD-derived grid points; Alemdar-2 and Hasanbey comprise raw GPS measurements. All data underpin the results of the related study.

Taken from sections of the report:

Introduction

The 2000/2001 Antarctic Geodesy Summer Program consisted of a number of distinct components. They included:

• ARGN reference mark surveys at Mawson and Davis.

• Orthometric height connections between the Mawson ARGN site (AUS064) and the Mawson TGBM (AUS258).

• Orthometric height connections between the Davis ARGN site (AUS099) and the Davis TGBM (AUS186).

• Connection by GPS to the Tide Gauge Benchmarks at Mawson, Davis and Larsemann Hills.

• Strengthen the Australian Antarctic Geodetic Network with GPS observations where possible.

• Establish a permanent Australian monument and connection to existing Chinese monuments in the Grove Mountains.

• Connect to Russian and Chinese Geodetic control points in the Larsemann Hills vicinity for datum unification.

• Derive ellipsoidal heights for lake benchmarks in the Vestfold Hills for the purpose of developing a geometric geoid model for that area.

The following report details the work completed in the 2000/2001 summer season, bu AUSLIG (Now Geoscience Australia) geodetic surveyors, Gary Johnston and Paul Digney between November 2000 and March 2001.