Control Points are locations with known coordinates in a defined geodetic spatial reference system and reported at a known level of accuracy. A further distinction can be drawn  between geodetic or government control monuments (whose co-ordinates and other properties are recorded in the Province’s MASCOT control database) versus various forms of Survey control point (which have coordinates derived by individual surveyors, as part of a specific project, and which are only tracked within the PMBC database).

The following table contains the Control Point attributes and descriptions.

Attribute NameDescription
GlobalID

Unique global identifier for the feature

Values: System-generated

Name

Unique identifier of a geodetic control monument or georeferenced point.

Values: For geodetic control, this is the GCM number from MASCOT. For control points received through surveyor submissions, it is a combination of Plan Number and a Description of the marker.

Notes: Other types of control point (i.e. GeoBC or field cadastral ties) are generally identified with a standard prefix (‘P’, ‘F’, etc.)

TabletMarking

Identifier of a geodetic control point as stamped on cap in field and recorded in MASCOT.

Values: Free text field

Notes: This is the description recorded in a survey plan.

HorizontalClass

The Horizontal Class field within the MASCOT Control database

Values: Integrated

Notes: More information can be found at MASCOT System Screen Generated Reports

Type

Describes the control point subtype

Values: See Control Type domain for more details.

PointID

Corresponding fabric point ID

Values: System-generated

Notes: A control point needs to be associated to a fabric point to be used in the fabric adjustment.

SurveyDate

The date the control point was surveyed/established.

Values: DD/MM/YYYY

Notes: Comes from source, either as the date of the last Coordinate revision (from the MASCOT database) or as the date a Field survey was completed.

Active

True if control point is active

Values: 0 (Inactive) or 1 (Active)

Notes: If true, control point has been associated to the fabric point referenced in the PointID field.

E

X-Coordinate of the point feature class in BC Albers

Values: System-generated

Notes: Spatial coordinates of the ArcGIS Point feature class, not the permanent coordinates of the Control Point itself.

N

Y-coordinate of the point feature class in BC Albers

Values: System-generated

Notes: Spatial coordinates of the ArcGIS Point feature class, not the permanent coordinates of the Control Point itself.

Z

Height of the fabric point in metres above mean sea level

Notes: Refer to the ‘AccuracyZ’ and ‘ElevationClass’ fields to understand how the ‘Z’ value was derived and the absolute positional accuracy of the elevation.

EAccuracy

Horizontal accuracy of the Control. A statistical estimate of the likelihood the reported coordinates are close to true location of the measured point.

Values: E-coordinate accuracy at 95% confidence level in metres

Notes: derived from the Standard Deviation in Longitude recorded in MASCOT; field only applies for geodetic control points.

NAccuracy

Horizontal accuracy of the Control. A statistical estimate of the likelihood the reported coordinates are close to true location of the measured point.

Values: N-coordinate accuracy at 95% confidence level in metres

Notes: derived from the Standard Deviation in Latitude recorded in MASCOT, field only applies for geodetic control points.

ZAccuracy

Z-coordinate (elevation) accuracy at 95% confidence level

Values: in Metres

Notes: Generally derived from metadata provided by a Surveyor during submission. A value of ‘10’ indicates that the elevation was estimated from a Digital Elevation Model and not surveyed.

OriginalSR

Defines the Spatial Reference System used for the original coordinates.

Values: See Original SR domain for more details.

OriginalRealization

Defines the realization, datum, and version used for the original coordinates.

Values: See Original Realization domain for more details.

SurveyMethod

The type of survey used to measure original coordinates of a control point.

Values: Free text field

Notes: If the survey plan type = “Survey” this will be populated from metadata by a Surveyor during submission. It will be the same as the ‘Georeferencing Method’ field of the survey plan that created the control.

PlanNumber

The name of the survey plan that created the control.

Notes: If the survey plan type = “Survey” this will be populated from metadata by a Surveyor during submission.

CreatedDate

Date when control point was entered in the fabric.

Values: System-generated

Notes: DD/MM/YYYY

ModifiedDate

Last date the control point record was modified in PMBC.

Values: System-generated

Notes: DD/MM/YYYY

Condition

Tracks the physical condition of a geodetic control point, as recorded in MASCOT.

Values: GOOD, ANOMALOUS, DESTROYED

Notes: ANOMALOUS indicates that the recorded coordinates are suspect and do not fit with the surrounding Control network.

OriginalX

The X coordinate in the original Spatial Reference System.

Values: Easting in a UTM NAD83 CSRS spatial reference

Notes: Surveyed X-Coordinate (optional) provided by Land Surveyors during submissions or from published values in MASCOT.

OriginalY

The Y coordinate in the original Spatial Reference System.

Values: Northing in a UTM NAD83 CSRS spatial reference

Notes: Surveyed Y-Coordinate (optional) provided by Land Surveyors during submissions or from published values in MASCOT.

OriginalZ

The surveyed orthometric height (elevation) provided by Land Surveyors during submissions or from published values in MASCOT.

Values: Metres above mean sea level

Notes: The vertical datum is not tracked by PMBC. Please refer to source (MASCOT or survey plan) for more details on the vertical datum used.

QualityClass

A record of the reliability of the published coordinates of a geodetic control point. From the MASCOT database.

Values: A, B, C, D, and E.

Notes: Class A is “very good”, Class B is “good”, Class C is “poor” and Class D is “very poor”. Class E means that the class is unknown, and it could be any of A to D.

OriginalEpoch

Defines the epoch for the datum realization.

Values: See Original Epoch domain for more details.

Notes: The values are for current standard BC realizations.

CombinedScaleFactor

Describes the ratio between Ground distances and projected UTM Grid Distances, at the control point location.

Notes: For control points = “Survey” this is populated from the surveyor submission metadata and is an average value for the plan.

Description

A general description of the physical location and/or appearance of a control point.

Values: Free text field

Notes: For geodetic control points, the Marker Location record from MASCOT. For Survey control, a general description of marker type provided by the Surveyor. For CAD Tie, this identifies which parcel corner was tied by the surveyor.

Shape

Contains geometry of the feature in the requested Spatial Reference.

Values: Point geometry

Notes: This is the geometry for the projected control point feature in the integrated parcel fabric and not the underlying component, ground based survey dimensions.

Error

Horizontal accuracy of the Control - A statistical estimate of the likelihood the reported coordinates are close to true location of the measured point.

Values: This is the semi-major axis of the error ellipse at a 95% confidence level (in metres).

Notes: This field only applies for non-geodetic control points. Populated from the surveyor submission metadata.

Surveyors calculate this value from GNSS observation. It is the same value labelled in a Survey Plan as ‘Estimated Horizontal Positional Accuracy’.

ErrorMinor

Horizontal accuracy of the Control - A statistical estimate of the likelihood the reported coordinates are close to true location of the measured point.

Values: This is the semi-minor axis of the error ellipse at a 95% confidence level (in metres).

Notes: This field only applies for non-geodetic control points. Populated from the surveyor submission metadata. See Error field for details.

ErrorAngle

Horizontal accuracy of the Control - A statistical estimate of the likelihood the reported coordinates are close to true location of the measured point.

Values: Azimuth of semi-major axis of error ellipse

Notes: This field only applies for non-geodetic control points. Populated from the surveyor submission metadata. See Error field for details.

SurveyType

The survey methodology used to measure coordinates for a control point.

Values: See Control Survey Type domain for more details.