BENCHMARKS_CORS_NOAA_IN.SHP contains locations for a total of 47 "Continuously Operating Reference Stations" (CORS) that were extracted from the assocatied layer named "BENCHMARKS_NOAA_IN.SHP" (which contains a total of 11,659 benchmark locations). Please visit the following CORS website of NOAA and NGS for more information: <http://www.ngs.noaa.gov/CORS/>
The following is excerpted from the CORS website maintained by by NOAA and the National Geodedic Survey (NGS):
"The National Geodetic Survey (NGS), an office of NOAA's National Ocean Service, manages a network of Continuously Operating Reference Stations (CORS) that provide Global Navigation Satellite System (GNSS) data consisting of carrier phase and code range measurements in support of three dimensional positioning, meteorology, space weather, and geophysical applications throughout the United States, its territories, and a few foreign countries.
"Surveyors, GIS users, engineers, scientists, and the public at large that collect GPS data can use CORS data to improve the precision of their positions. CORS enhanced post-processed coordinates approach a few centimeters relative to the National Spatial Reference System, both horizontally and vertically.
"The CORS network is a multi-purpose cooperative endeavor involving government, academic, and private organizations. The sites are independently owned and operated. Each agency shares their data with NGS, and NGS in turn analyzes and distributes the data free of charge. As of August 2015, the CORS network almost 2,000 stations, contributed by over 200 different organizations, and the network continues to expand."
The following is excerpted from the CORS website maintained by by NOAA and the National Geodedic Survey (NGS):
"The National Geodetic Survey (NGS), an office of NOAA's National Ocean Service, manages a network of Continuously Operating Reference Stations (CORS) that provide Global Navigation Satellite System (GNSS) data consisting of carrier phase and code range measurements in support of three dimensional positioning, meteorology, space weather, and geophysical applications throughout the United States, its territories, and a few foreign countries.
"Surveyors, GIS users, engineers, scientists, and the public at large that collect GPS data can use CORS data to improve the precision of their positions. CORS enhanced post-processed coordinates approach a few centimeters relative to the National Spatial Reference System, both horizontally and vertically.
"The CORS network is a multi-purpose cooperative endeavor involving government, academic, and private organizations. The sites are independently owned and operated. Each agency shares their data with NGS, and NGS in turn analyzes and distributes the data free of charge. As of August 2015, the CORS network almost 2,000 stations, contributed by over 200 different organizations, and the network continues to expand."
The following is excerpted from the NOAA metadata:
"Geodetic Data are in the public domain, not restricted from access or distribution."
This data set was compiled by Indiana University, Indiana Geological Survey, using data believed to be accurate; however, a degree of error is inherent in all data. This product is distributed "AS-IS" without warranties of any kind, either expressed or implied, including but not limited to warranties of suitability to a particular purpose or use. No attempt has been made in either the design or production of these data to define the limits or jurisdiction of any federal, state, or local government. These data are intended for use only at the published scale or smaller and are for reference purposes only. They are not to be construed as a legal document or survey instrument. A detailed on-the-ground survey and historical analysis of a single site may differ from these data.
CREDIT
It is requested that the Indiana Geological Survey be cited in any products generated from this data. The following source citation should be included: [BENCHMARKS_CORS_NOAA_IN: Continuously Operating Reference Station (CORS) Locations in Indiana (National Oceanic and Atmospheric Administration, Point Shapefile), 20151203].
WARRANTY
Indiana University, Indiana Geological Survey warrants that the media on which this product is stored will be free from defect in materials and workmanship for ninety (90) days from the date of acquisition. If such a defect is found, return the media to Publication Sales, Indiana Geological Survey, 611 North Walnut Grove Avenue, Bloomington, Indiana 47405 2208, and it will be replaced free of charge.
LIMITATION OF WARRANTIES AND LIABILITY
Except for the expressed warranty above, the product is provided "AS IS", without any other warranties or conditions, expressed or implied, including, but not limited to, warranties for product quality, or suitability to a particular purpose or use. The risk or liability resulting from the use of this product is assumed by the user. Indiana University, Indiana Geological Survey shares no liability with product users indirect, incidental, special, or consequential damages whatsoever, including, but not limited to, loss of revenue or profit, lost or damaged data or other commercial or economic loss. Indiana University, Indiana Geological Survey is not responsible for claims by a third party. The maximum aggregate liability to the original purchaser shall not exceed the amount paid by you for the product.
The following is excerpted from the NOAA metadata:
"Not restricted; Geodetic Data, including software were developed and compiled with U.S. Government funding; no proprietary rights may be attached to them nor may they be sold to the U.S. Government as part of any procurement of ADP products or services."
"NOAA, National Geodetic Survey and cooperating organizations."
The following is excerpted from the NOAA metadata:
"The data was extracted from NGS datasheets which are available at < <http://www.ngs.noaa.gov/datasheets/> >. The NGS datasheet is a text document which summarizes key geodetic information stored in the NGS database."
"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:
< <http://www.ngs.noaa.gov/datasheets/> >
"Vertical 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 station have Latitude, Longitudes displayed to 2 or 3 places and are identified by attribute ELEV_SRCE of ADJUSTED, ADJ UNCH, POSTED,READJUST,N HEIGHT,RESET,COMPUTED
"Lesser quality Orthometric Heights may also be preset in the dataset. These are identified by a POS_SRCE attributes GPS_OBS, VERT_ANG, H_LEVEL, VERTCON, SCALED. These lesser quality orthometric heights are described at:
< <http://www.ngs.noaa.gov/datasheets/> >
"IMPORTANT - 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 <http://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.
"The attributes 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 attribure 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 <http://www.ngs.noaa.gov/TOOLS/Vertcon/vertcon.html> for a more detailed explaination 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 meters."
"95 percent confidence level for geodetic quality data."
"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."
"FGCS sponsored testing in cooperation with equipment manufacturers and National Institutes of Standards and Technology, Gaithersburg, MD 20850."
"This dataset DOES NOT include destroyed marks. All other non-publishable marks are NOT included. Non-publishable criteria is available at < <http://www.ngs.noaa.gov/cgi-bin/craigs_lib.prl?HELP_NONPUB=1> >."
"The description of tests are explained in 'Geometric Geodetic Accuracy Standards and Specifications For Using GPS Relative Positioning Techniques,' FGCS (formally FGCC) publication version 5.0, 1989."
"Horizontal positional accuracy statements pertain to horizontal control stations only. i.e. Those with geodetic quality Latitude, Longitudes. The positional Accuracy explanation contained in "Geometric Geodetic Accuracy Standards and Specifications For Using GPS Relative Positioning Techniques," FGCS (formally FGCC) publication version 5.0, 1989, (See table 1, p6). with the exception of Order A and Order B which have an accuracy of as described at: < <http://www.ngs.noaa.gov/cgi-bin/ds_lookup.prl?Item=HORZ%20ORDER> >."
"The description of tests are explained in "Geometric Geodetic Accuracy Standards and Specifications for Using GPS Relative Positioning Techniques," FGCS (formally FGCC) publication version 5.0, 1989, (See table 1, p6)."
"Vertical positional accuracy statements pertain to vertical control stations only. i.e. Those with geodetic quality Orthometric Heights. Orthometric Height accuracy explanation is contained in FGDC publication "Standards and Specifications for Geodetic Control Networks" with the exception of vertical control of class 0 POSTED and READJUSTED Heights which are described at: < <http://www.ngs.noaa.gov/cgi-bin/ds_lookup.prl?Item=VERT%20ORDER> >
"Ellipsoid height accuracy explanation contained in "Geometric Geodetic Accuracy Standards and Specifications for Using GPS Relative Positioning Techniques," FGCS (formally FGCC) publication version 5.0, 1989. (see table 1, p6). The accuracies for ellipsoid heights are described at: < <http://www.ngs.noaa.gov/cgi-bin/ds_lookup.prl?Item=ELLP%20ORDER> >."
The following is excerpted from the NOAA metadata:
"The geodetic data must be submitted in the digital formats specified in the FGCS (formally FGCC) publication "Input Formats and Specifications of the National Geodetic Survey Data Base" which describes the formats and procedures for submission of data for adjustment and assimilation into the National Geodetic Survey Data Base. Separate volumes of this publication refer to horizontal (volume 1), vertical (volume 2), and gravity (volume 3) control, and are available from NOAA, National Geodetic Survey, 1315 East-West Hwy, Code N/CGS1, Silver Spring, MD, 20910 (1-301-713-3242). Note guidelines for submission of three-dimensional Global Positioning System (GPS) relative positioning data are contained in annex L to volume 1."
"The National Geodetic Survey produces geodetic data. Geodetic data comprise the results of geodetic surveys to determine, among other things, latitude, longitude, height, scale, and orientation control. The National Geodetic Survey original field survey project observations and final reports are accessioned into records system of the National Archives and Records Administration of the U.S.A. These surveys provide information valuable for a variety of uses in the mapping, charting and surveying community.
"The NGS' final product is the geodetic data sheet. Geodetic data sheets are comprehensive summaries of all published information for a given geodetic reference point, including: the geographic position and/or height based on the current reference datum, condition of the survey mark when it was last visited, a description of where the point is located and how to reach it, and an explanation of the terms used in the data sheet. In support of these geodetic data, the NGS provides software, publications, and various user services, including geodetic advisor program, instrument calibration, surveying standards, and technical workshops.
"This dataset contains certain information extracted from the above mentioned data sheet."
<http://www.ngs.noaa.gov/cgi-bin/datasheet.prl>
The shapefiles that were downloaded were those specified as "Any Horiz. and/or Vert. Control" and "Any stability." The shapefiles were then imported into ESRI ArcView 3.3 and merged together using the Geoprocessing Wizard. The resulting merged shapefile was then re-projected in ESRI ArcToolbox 9.0 from Geographic Coordinates to UTM Zone 16 NAD83 coordinates.
"The current attributes and their meaning are shown below:
#FeatureId - Temporary unique ID assigned to this station.
DATA_DATE - The date when this information was retrieved from the NGS database.
DATA_SRCE - Data Source where the information for the mark came from. You should use this link to obtain a full datasheet for the mark or obtain the datasheets from <http://www.ngs.noaa.gov/cgi-bin/datasheet.prl> if you intend to use the data for survey control.
DEC_LONG - Decimal equivalent of the LONGITUDE Always displayed to 10 decimal places, but you should see POS_SRCE and POS_ORDER to determine the true accuracy.
DEC_LAT - Decimal equivalent of the LATITUDE
PID - Permanent Identifier assigned by NGS to each mark
NAME - Station Name (a.k.a. Designation)
STATE - State Code
COUNTY - County Name
QUAD - USGS Topographic Quad Map Name
LATITUDE - Latitude in Deg-Min-Sec format
LONGITUDE - Longitude in Deg-Min-Sec format
POS_DATUM - Datum of the LATITUDE,LONGITUDE Should always be NAD83
DATUM_TAG - Datum Tag of the LATITUDE,LONGITUDE NAD83 (1986) indicates positions on the NAD83 datum for the North American Adjustment, completed in 1986. NAD83 (nnnn) indicates positions on the NAD83 datum for the North American Adjustment, but readjusted to a State High Accuracy Reference Network (HARN) on the date shown in (nnnn). NAD83 (CORS) indicates positions which are part of the CORS network.
POS_SRCE - Position Source for the LATITUDE,LONGITUDE
ADJUSTED = Least squares adjustment. (Lat,Lon Rounded to 5 decimal places.)
HD_HELD1 = Differentially corrected hand held GPS observations. (Lat,Lon Rounded to 2 decimal places.)
HD_HELD2 = Autonomous hand held GPS observations. (Lat,Lon Rounded to 1 decimal places.)
SCALED = Scaled from a topographic map. (Lat,Lon Rounded to 0 decimal places.)
ELEVATION - Present if available. The Orthometric Height in METERS inicating the height above the Geoid.
ELEV_DATUM - Datum of the ELEVATION
ELEV_SRCE - Elevation Source for the ELEVATION
ADJUSTED = Direct Digital Output from Least Squares Adjustment of Precise Leveling. (Rounded to 3 decimal places.)
ADJ UNCH = Manually Entered (and NOT verified) Output of Least Squares Adjustment of Precise Leveling. (Rounded to 3 decimal places.)
POSTED = Pre-1991 Precise Leveling Adjusted to the NAVD 88 Network After Completion of the NAVD 88 General Adjustment of 1991. (Rounded to 3 decimal places.)
READJUST = Precise Leveling Readjusted as Required by Crustal Motion or Other Cause. (Rounded to 2 decimal places.)
N HEIGHT = Computed from Precise Leveling Connected at Only One Published Bench Mark. (Rounded to 2 decimal places.)
RESET = Reset Computation of Precise Leveling. (Rounded to 2 decimal places.)
COMPUTED = Computed from Precise Leveling Using Non-rigorous Adjustment Technique. (Rounded to 2 decimal places.)
LEVELING = Precise Leveling Performed by Horizontal Field Party. (Rounded to 2 decimal places.)
H LEVEL = Level between control points not connected to bench mark. (Rounded to 1 decimal places.)
GPS OBS = Computed from GPS Observations. (Rounded to 1 decimal places.)
VERT ANG = Computed from Vertical Angle Observations. (Rounded to 1 decimal place; If No Check, to 0 decimal places.)
SCALED = Scaled from a Topographic Map. (Rounded to 0 decimal places.)
U HEIGHT = Unvalidated height from precise leveling connected at only one NSRS point. (Rounded to 2 decimal places.)
VERTCON = The NAVD 88 height was computed by applying the VERTCON shift value to the NGVD 29 height. (Rounded to 0 decimal places.)
ELLIP_HT - Present if available. The ellipsoid height in METERS referenced to GRS80 ellipsoid.
ELLIP_SRCE - Ellipsoid Ht Source for the ELLIP_HT Should always be GPS_OBS when present.
POS_ORDER - Order of accuracy for the LATITUDE,LONGITUDE (should be one of the following values A,B,1,2,3). Order and class for Orders 1, 2, and 3 are defined in the Federal Geodetic Control Committee publication "Standards and Specifications for Geodetic Control Networks".
In addition -
Order A stations have a relative accuracy of 5 mm +/- 1-10,000,000 relative to other A-order stations.
Order B stations have a relative accuracy of 8 mm +/- 1- 1,000,000 relative to other A- and B-order stations.
POS_CHECK - Y = Observational Check was made for the position, N = NO Observational Check was made for the positions
ELEV_ORDER - Order of accuracy for the ELEVATION Should be 1,2, or 3 for Vertical Control Stations. Will be blank for stations used for Horizontal Control only. Also see attribute DIST_RATE which is used for some vertical control stations. Elevation order and class for 1, 2, and 3 are defined in the Federal Geodetic Control Committee publication "Standards and Specifications for Geodetic Control Networks". In addition -
Vertical control which were determined only for the purpose of supplying a height for Horizontal Distance Reductions are assigned an order of 3.
Class 0 is used for special cases of orthometric vertical control as follows-
Vertical Order/Class Tolerance Factor
-------------------- ----------------
1 class 0 2.0 mm or less
2 class 0 8.4 mm or less
3 class 0 12.0 mm or less
ELEV_CLASS - Should be 0, 1, or 2 See details under ELEV_ORDER
ELEV_CHECK - Y = Observational Check was made for the orthometric height, N = NO Observational Check was made for the orthometric heights
VERTCONED - Y=Orthometric Height was determined by applying VERTCON to an old NGVD 29 height. N = Orthometric Height determined by observations.
DIST_RATE- Distribution rate for POSTED and READJUSTED benchmarks which do not have an Order and Class are as follows "Posted bench marks" are vertical control points in the NGS data base which were excluded from the NAVD 88 general adjustment. Some of the bench marks were excluded due to large adjustment residuals, possibly caused by vertical movement of the bench marks during the time interval between different leveling epochs. Adjusted NAVD 88 are computed for posted bench marks by supplemental adjustments.
A range of mean distribution rate corrections is listed for each posted bench mark in the data portion of the publication. A summary table of the mean distribution rates and their codes is listed below. The mean distribution rate corrections which were applied to the original leveling observations is a good indication of the usefulness of the posted bench marks' adjusted NAVD 88 heights.
Distribution Rate Code Distribution Rate Correction
---------------------- ----------------------------
"a" 0.0 thru 1.0 mm/km
"b" 1.1 thru 2.0 "
"c" 2.1 thru 3.0 "
"d" 3.1 thru 4.0 "
"e" 4.1 thru 8.0 "
"f" greater than 8.0 mm/km
POSTED BENCH MARKS SHOULD BE USED WITH CAUTION. As is the case for all leveling projects, the manditory FGCS check leveling two-mark or three-mark tie procedure will usually detect any isolated movement (or other problem) at an individual bench mark. Of course, regional movement affecting all the marks equally is not detected by the two- or three-mark tie procedure.
ELLP_ORDER - Order of accuracy for the ELLIP_HT Should be 1,2,3,4, or 5 if present. The following ellipsoid height order and class relative accuracy standards have not yet been adopted by the Federal Geodetic Control Subcommittee, but are currently in use by NGS-
Ellipsoid Height Classification Maximum Height Difference Accuracy
------------------------------- -----------------------------------
1 class 1 0.5 (mm)/sqrt(km)
1 class 2 0.7
2 class 1 1.0
2 class 2 1.3
3 class 1 2.0
3 class 2 3.0
4 class 1 6.0
4 class 2 15.0
5 class 1 30.0
5 class 2 60.0
The ellipsoid height difference accuracy (b) is computed from a a minimally constrained correctly weighted least squares adjustment by the following formula [ b = s / sqrt(d) ]. Where "b" = height difference accuracy, "s" = propagated standard deviation of ellipsoid height difference in millimeters between control points obtained from the least squares adjustment, and "d" = horizontal distance between control points in kilometers
ELLP_class - Class of accuracy for ELLIP_HT Should be 1 or 2 See details under ELLP_ORDER
1_RECV - Date when the station was first monumented or in the case of landmarks, first observed.
LAST_RECV - Date when the station was last recovered.
LAST_COND - Last recovered condition of the mark. Should be one of the following-
MONUMENTED
1 OBSERVED
GOOD
POOR
MARK NOT FOUND
SEE DESCRIPTION
DESTROYED
LAST_RECBY - Agency who reported the last condition of the mark.
STABILITY - The stability of the mark may have 1 of 4 codes as indicated below:
A = MOST RELIABLE AND EXPECTED TO HOLD POSITION/ELEVATION WELL
B = PROBABLY HOLD POSITION/ELEVATION WELL
C = MAY HOLD, BUT OF TYPE COMMONLY SUBJECT TO SURFACE MOTION - E.G. FROST HEAVE, ETC.
D = MARK OF QUESTIONABLE OR UNKNOWN STABILITY
HT_MOD - Designates if this site is a Height Modernization site. Y - Yes.
CORS_ID - Continuously Operating Reference Stations (CORS) site ID.
PACS_SACS - Designates whether this is a Primary Airport Control Station (PACS) or Secondary Airport Control Station (SACS).
GEOID_HT - Present if available. The geoid height in METERS referenced to the geoid model attribute.
NET_ACC_HZ - The horizontal network accuracy to the 95 percent confidence level CM.
NET_ACC_EL - The horizontal network accuracy to the 95 percent confidence level CM.
ECEF_X - The computed Earth-Centered, Earth-Fixed X position.
ECEF_Y - The computed Earth-Centered, Earth-Fixed Y position.
ECEF_Z - The computed Earth-Centered, Earth-Fixed Z position.
SPC_ZONE - The State Plane Coordinate Zone.
SPC_NORTH - The State Plane Coordinate Northing.
SPC_EAST - The State Plane Coordinate Easting.
SPC_CONV - The State Plane Coordinate Convergence Angle.
SPC_CSF - The State Plane Coordinate Combined Scale Factor.
UTM_ZONE - The Universal Transverse Mercator Zone.
UTM_NORTH - The Universal Transverse Mercator Northing.
UTM_EAST - The Universal Transverse Mercator Easting.
UTM_CONV - The Universal Transverse Mercator Convergence Angle.
UTM_CSF - The Universal Transverse Mercator Combined Scale Factor.
DYNAMIC_HT - The computed dynamic height at a bench mark using the orthometric height referenced the NAVD 88 and a gravity value.
MODELEDGRAV - The interpolated gravity value which was used in the NAVD 88 general adjustment.
MARKER - Identifies the type of marker.
SETTING - Identifies the type of setting.
STAMPING - Identifies the stamping on the disk.
CORS_URL - (Added by IGS personnel) Website link to the individual CORS site webpage where photos and download of post-processing data can be accessed.
"All values were obtained from the NGA Datasheet available at <http://www.ngs.noaa.gov/cgi-bin/datasheet.prl>"
It is requested that the Indiana Geological Survey be cited in any products generated from this data. The following source citation should be included: [BENCHMARKS_CORS_NOAA_IN: Continuously Operating Reference Station (CORS) Locations in Indiana (National Oceanic and Atmospheric Administration, Point Shapefile), 20151203].
WARRANTY
Indiana University, Indiana Geological Survey warrants that the media on which this product is stored will be free from defect in materials and workmanship for ninety (90) days from the date of acquisition. If such a defect is found, return the media to Publication Sales, Indiana Geological Survey, 611 North Walnut Grove Avenue, Bloomington, Indiana 47405 2208, and it will be replaced free of charge.
LIMITATION OF WARRANTIES AND LIABILITY
Except for the expressed warranty above, the product is provided "AS IS", without any other warranties or conditions, expressed or implied, including, but not limited to, warranties for product quality, or suitability to a particular purpose or use. The risk or liability resulting from the use of this product is assumed by the user. Indiana University, Indiana Geological Survey shares no liability with product users indirect, incidental, special, or consequential damages whatsoever, including, but not limited to, loss of revenue or profit, lost or damaged data or other commercial or economic loss. Indiana University, Indiana Geological Survey is not responsible for claims by a third party. The maximum aggregate liability to the original purchaser shall not exceed the amount paid by you for the product.