FLORIDA GEOGRAPHIC DATA LIBRARY DOCUMENTATION

TITLE: HORIZONTAL AND VERTICAL GEODETIC CONTROL DATA FOR FLORIDA - MAY 2014

Geodataset Name:       NGS_POINTS_MAY14
Geodataset Type:       SHAPEFILE
Geodataset Feature:    Point
Feature Count:         50640
GENERAL DESCRIPTION:
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.
DATA SOURCE(S):                    National Oceanic and Atmospheric Administration, National Geodetic Survey
SCALE OF ORIGINAL SOURCE MAPS:     Unknown
GEODATASET EXTENT:                 State of Florida
PUBLICATION DATE: 2004 TIME PERIOD OF CONTENT: 20140519 DOWNLOAD LINK: http://www.fgdl.org/metadataexplorer/explorer.jsp

FEATURE ATTRIBUTE TABLES:

Datafile Name: NGS_POINTS_MAY14.DBF
ITEM NAME WIDTH TYPE
OBJECTID
4 OID
Shape
4 Geometry
FeatureId
2 SmallInteger
DATA_DATE
8 String
DATA_SRCE
57 String
DEC_LONG
15 String
DEC_LAT
13 String
PID
6 String
NAME
40 String
STATE
2 String
COUNTY
26 String
QUAD
40 String
LATITUDE
17 String
LONGITUDE
18 String
POS_DATUM
6 String
DATUM_TAG
6 String
POS_SRCE
12 String
ELEVATION
9 String
ELEV_DATUM
12 String
ELEV_SRCE
12 String
ELLIP_HT
9 String
ELLIP_SRCE
12 String
POS_ORDER
1 String
POS_CHECK
1 String
ELEV_ORDER
1 String
ELEV_CLASS
1 String
ELEV_CHECK
1 String
DIST_RATE
1 String
ELLP_ORDER
1 String
ELLP_CLASS
1 String
FIRST_RECV
8 String
LAST_RECV
8 String
LAST_COND
16 String
LAST_RECBY
6 String
SAT_USE
1 String
SAT_DATE
8 String
STABILITY
1 String
DESCRIPT
50 String
FGDLAQDATE
36 Date
AUTOID
4 Integer

FEATURE ATTRIBUTE TABLES CODES AND VALUES:

Item
Item Description
OBJECTID Internal feature number.

Shape Feature geometry.

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 indicating 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- 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 Observational 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-
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 Observational Check
Y = Observational Check was made for the orthometric height,

N = NO Observational Check was made for the orthometric heights


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. POSTED BENCH MARKS SHOULD BE USED WITH CAUTION. As is the case for all leveling projects, the mandatory 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.
a = 0.0 thru 1.0 mm/km

b = 1.1 thru 2.0 mm/km

c = 2.1 thru 3.0 mm/km

d = 3.1 thru 4.0 mm/km

e = 4.1 thru 8.0 mm/km

f = greater than 8.0 mm/km


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-. The ellipsoid height difference accuracy (b) is computed from a a minimally constrained correctly weighted least squares adjustment by - 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. d = horizontal distance between control points in kilometers
order 1 - class 1 = 0.5 (mm)/sqrt(km)

order 1 - class 2 = 0.7 (mm)/sqrt(km)

order 2 - class 1 = 1.0 (mm)/sqrt(km)

order 2 - class 2 = 1.3 (mm)/sqrt(km)

order 3 - class 1 = 2.0 (mm)/sqrt(km)

order 3 - class 2 = 3.0 (mm)/sqrt(km)

order 4 - class 1 = 6.0 (mm)/sqrt(km)

order 4 - class 2 = 15.0 (mm)/sqrt(km)

order 5 - class 1 = 30.0 (mm)/sqrt(km)

order 5 - class 2 = 60.0 (mm)/sqrt(km)


ELLP_CLASS Class of accuracy for ELLIP_HT Should be 1 or 2 See details under ELLP_ORDER

FIRST_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 FIRST OBSERVED GOOD POOR MARK NOT FOUND SEE DESCRIPTION DESTROYED

LAST_RECBY Agency who reported the last condition of the mark.

SAT_USE Undefined by Source

SAT_DATE Undefined by Source

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


DESCRIPT GeoPlan added field based on QUAD

FGDLAQDATE Date GeoPlan acquired data from source

AUTOID Unique ID added by GeoPlan


USER NOTES:
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>
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/cgi-bin/ds_lookup.prl?Item=SCALED>

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 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,COMPUTED

Lesser 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:
<http://www.ngs.noaa.gov/cgi-bin/ds_lookup.prl?Item=SCALED>

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.

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 <http://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 meters

Provide a base of reference for latitude, longitude and height
throughout the United States.

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.

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).

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.

The Florida Geographic Data Library is a collection of Geospatial Data
compiled by the University of Florida GeoPlan Center with support from
the Florida Department of Transportation. GIS data available in FGDL is
collected from various state, federal, and other agencies (data sources)
who are data stewards, producers, or publishers. The data available in
FGDL may not be the most current version of the data offered by the
data source. University of Florida GeoPlan Center makes no guarantees
about the currentness of the data and suggests that data users check
with the data source to see if more recent versions of the data exist.

Furthermore, the GIS data available in the FGDL are provided 'as is'.
The University of Florida GeoPlan Center makes no warranties, guaranties
or representations as to the truth, accuracy or completeness of the data
provided by the data sources. The University of Florida GeoPlan Center
makes no representations or warranties about the quality or suitability
of the materials, either expressly or implied, including but not limited
to any implied warranties of merchantability, fitness for a particular
purpose, or non-infringement. The University of Florida GeoPlan Center
shall not be liable for any damages suffered as a result of using,
modifying, contributing or distributing the materials.

A note about data scale: 

Scale is an important factor in data usage.  Certain scale datasets
are not suitable for some project, analysis, or modeling purposes.
Please be sure you are using the best available data. 

1:24000 scale datasets are recommended for projects that are at the
county level.
1:24000 data should NOT be used for high accuracy base mapping such
as property parcel boundaries.
1:100000 scale datasets are recommended for projects that are at the
multi-county or regional level.
1:125000 scale datasets are recommended for projects that are at the
regional or state level or larger.

Vector datasets with no defined scale or accuracy should be
considered suspect. Make sure you are familiar with your data
before using it for projects or analysis. Every effort has been
made to supply the user with data documentation. For additional
information, see the References section and the Data Source Contact
section of this documentation. For more information regarding
scale and accuracy, see our webpage at:
http://geoplan.ufl.edu/education.html

REFERENCES:
National Geodetic Survey:
http://www.ngs.noaa.gov/

DATA LINEAGE SUMMARY:
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.
Process Date: Not complete

GeoPlan downloaded this data in on May 22nd, 2014 from the following website: http://www.ngs.noaa.gov/cgi-bin/datasheet.prl When downloaded the data was in shapefile format. The data was projected from GCS NAD83 HARN to the FGDL Albers NAD83 HARN projection. - Changed name from fl.shp to ngs_points_may14.shp - A DESCRIPT field was added based on QUAD. - A FGDLAQDATE field was added based on date GeoPlan acquired the data from the source. Process Date: 20140522
MAP PROJECTION PARAMETERS:

Projection                          ALBERS
Datum                               HPGN
Units                               METERS
Spheroid                            GRS1980
1st Standard Parallel               24  0  0.000
2nd Standard Parallel               31 30  0.000
Central Meridian                   -84 00  0.000
Latitude of Projection's Origin     24  0  0.000
False Easting (meters)              400000.00000
False Northing (meters)             0.00000

DATA SOURCE CONTACT (S):

Name:
Abbr. Name:
Address:


Phone:

Web site:
E-mail:
Contact Person:
         Phone:
        E-mail:
National Oceanic & Atmospheric Administration, National Geodetic Survey
NOAA, NGS
SSMC2/9152 1315 East-west Highway
Silver Spring, MD
20910
301-713-3242

http://www.ngs.noaa.gov/cgi-bin/datasheet.prl ngs.software@noaa.gov NGS Information Services Branch

FGDL CONTACT:
Name:                   FLORIDA GEOGRAPHIC DATA LIBRARY
Abbr. Name:             FGDL
Address:                Florida Geographic Data Library
                        431 Architecture Building
                        PO Box 115706
                        Gainesville, FL  32611-5706
Web site:               http://www.fgdl.org

Contact FGDL: 

      Technical Support:	        http://www.fgdl.org/fgdlfeed.html
      FGDL Frequently Asked Questions:  http://www.fgdl.org/fgdlfaq.html
      FGDL Mailing Lists:		http://www.fgdl.org/fgdl-l.html
      For FGDL Software:                http://www.fgdl.org/software.html