Managing a Cadastral SDI Framework Built from Boundary Data
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Transcript of Managing a Cadastral SDI Framework Built from Boundary Data
Managing a Cadastral SDI Managing a Cadastral SDI Framework Built from Framework Built from
Boundary DataBoundary Data
Michael ElfickMichael ElfickTim HodsonTim HodsonCurt WilkinsonCurt Wilkinson
AgendaAgenda
Introduction – Current situationIntroduction – Current situationBackground and Design ConceptsBackground and Design ConceptsData ModelData ModelWorkflowWorkflow
The influence of GPSThe influence of GPS
GPS enabled systems will be GPS enabled systems will be everywhereeverywhere
To make GPS truly valuable, GIS To make GPS truly valuable, GIS must supply underlying mapping must supply underlying mapping informationinformation
This information must be accurateThis information must be accurateAccurate data greatly extends the Accurate data greatly extends the
usefulness of GISusefulness of GIS
Typical errors in digitized dataTypical errors in digitized data
GoalGoalA simple system to create and manage A simple system to create and manage
spatially accurate cadastral geometry in a spatially accurate cadastral geometry in a GIS.GIS.
The system must be extendable and:The system must be extendable and:
Follow survey methodsFollow survey methods
Be able to improve existing datasetsBe able to improve existing datasets
Maintain spatial relationships between the Maintain spatial relationships between the Cadastre and associated GIS layers.Cadastre and associated GIS layers.
Scope of TechnologyScope of Technology
Focus on cadastral geometryFocus on cadastral geometrynot a full cadastral systemnot a full cadastral system
A key part of a GIS systemA key part of a GIS systemDesigned to be an extendable Designed to be an extendable
platformplatformFor land records and cadastreFor land records and cadastreComplements a civil and survey systemComplements a civil and survey system
Cadastral FabricCadastral Fabric
The fabric is a The fabric is a continuous surfacecontinuous surface of of connected parcelsconnected parcels
It is also a dimensioned It is also a dimensioned boundary networkboundary network Has an Has an explicit topologyexplicit topology, defined by , defined by
common parcel corners and neighborscommon parcel corners and neighbors Topology is inherent in the model, and is Topology is inherent in the model, and is
defined and enforced during data entrydefined and enforced during data entry
Survey MeasurementsSurvey Measurements
In the past, measures of bearing and In the past, measures of bearing and distance were much easier than fixing a distance were much easier than fixing a location on the surface of the earthlocation on the surface of the earth
Land surveys are parcel dimensions, Land surveys are parcel dimensions, with known error in the measureswith known error in the measures
Parcels are also defined by their relation Parcels are also defined by their relation to other parcels to other parcels
So, measures and connections were known, but true coordinates were not
From From MeasuresMeasures to to CoordinatesCoordinates
We need accurate coordinates for the We need accurate coordinates for the fabricfabric and associated GIS layers and associated GIS layers
Accurate coordinates are close to the Accurate coordinates are close to the truetrue coordinates coordinatesImplies there is a real object (not always)Implies there is a real object (not always)and we know how close (statistic of error)and we know how close (statistic of error)
For Instance, Control Points have:For Instance, Control Points have:A physical location (monument)A physical location (monument)Error information (level of confidence)Error information (level of confidence)
Central ConceptsCentral Concepts Often, associated GIS layers are created Often, associated GIS layers are created
and maintained in context with the and maintained in context with the CadastreCadastre
An accurate Cadastre can serve as the An accurate Cadastre can serve as the ‘control’ for the rest of the GIS‘control’ for the rest of the GIS
If we capture the shifts in coordinates of If we capture the shifts in coordinates of the Cadastre, we can then adjust the the Cadastre, we can then adjust the associated layers and maintain spatial associated layers and maintain spatial relationshipsrelationships
The result is more accurate coordinates all The result is more accurate coordinates all aroundaround
Central Design ConceptCentral Design Concept
Differentiation of Source information Differentiation of Source information from derived informationfrom derived information
ESR Shapes Coordinates Measurements
Derived from Coordinates
Computed from LSA – held by Points
From Survey or Records – held by the Line
Editable by standard GIS
Edited only by Cadastral Editor
Parcels are the ‘Parcels are the ‘unit of workunit of work’’Create & edit Create & edit parcelsparcelsJoin Join parcelsparcels to the fabric to the fabric
Control points ‘Control points ‘fix’ fix’ the fabricthe fabricConnected (and historic) parcels have Connected (and historic) parcels have
redundancyredundancy of measurementsof measurementsMultiple measurements & control Multiple measurements & control
points processed in a points processed in a least squares least squares adjustmentadjustment
Fabric FundamentalsFabric Fundamentals
Parcel ModelParcel Model
Parcels are represented by :Parcels are represented by :parcel lineparcel line features, features, parcel pointparcel point features, and features, and parcel polygonparcel polygon features, features, referred to in aggregate as referred to in aggregate as parcel featuresparcel features
Survey Database feature classParcels
Data typeField nameAllow nulls
OBJECTID Object ID SHAPE Geometry YesJoined Short integer No
ParcelName String NoPlanID Long integer No
ParcelType Short integer NoStatedArea Double YesCompiled Short integer No
TrueMidBrg Short integer NoHistorical Short integer No
SytemStartDate Date NoSystemEndDate Date NoLegalStartDate Date YesLegalEndDate Date Yes
SHAPE_Length Double YesSHAPE_Area Double Yes
CentroidX Double YesCentroidY Double Yes
AccuracyID Long integer No
Survey Database feature classLines
Data typeField nameAllow nulls
OBJECTID Object ID SHAPE Geometry YesJoined Short integer No
ParcelID Long integer NoSequence Long integer YesFromPoint Long integer No
ToPoint Long integer NoBearing Double YesDistance Double YesLineType Short integer NoRadius Double Yes
ArcDistance Double YesDelta Double Yes
CenterPoint Long integer YesHistorical Short integer No
SHAPE_Length Double YesRadialBearing Double Yes
TangentBearing Double YesEntryParameters Short integer No
AccuracyID Long integer Yes
Survey Database feature classPoints
Data typeField nameAllow nulls
OBJECTID Object ID SHAPE Geometry YesJoined Short integer No
PointCode String YesPointName String YesHistorical Short integer NoRemarks String Yes
Contourable Short integer NoSystemStartDate Date YesSystemEndDate Date YesLegalStartDate Date YesLegalEndDate Date Yes
Parcel
Parcel ModelParcel Model
Parcels are defined by Parcels are defined by non-spatial datanon-spatial data, and , and Parcels have Parcels have spatial dataspatial data – dimensions on lines – dimensions on lines
Survey Database feature classParcels
Data typeField nameAllow nulls
OBJECTID Object ID SHAPE Geometry YesJoined Short integer No
ParcelName String NoPlanID Long integer No
ParcelType Short integer NoStatedArea Double YesCompiled Short integer No
TrueMidBrg Short integer NoHistorical Short integer No
SytemStartDate Date NoSystemEndDate Date NoLegalStartDate Date YesLegalEndDate Date Yes
SHAPE_Length Double YesSHAPE_Area Double Yes
CentroidX Double YesCentroidY Double Yes
AccuracyID Long integer No
Survey Database feature classLines
Data typeField nameAllow nulls
OBJECTID Object ID SHAPE Geometry YesJoined Short integer No
ParcelID Long integer NoSequence Long integer YesFromPoint Long integer No
ToPoint Long integer NoBearing Double YesDistance Double YesLineType Short integer NoRadius Double Yes
ArcDistance Double YesDelta Double Yes
CenterPoint Long integer YesHistorical Short integer No
SHAPE_Length Double YesRadialBearing Double Yes
TangentBearing Double YesEntryParameters Short integer No
AccuracyID Long integer Yes
Relationship class
One to many
Parcel_Lines
Survey Database feature classPoints
Data typeField nameAllow nulls
OBJECTID Object ID SHAPE Geometry YesJoined Short integer No
PointCode String YesPointName String YesHistorical Short integer NoRemarks String Yes
Contourable Short integer NoSystemStartDate Date YesSystemEndDate Date YesLegalStartDate Date YesLegalEndDate Date Yes
Survey Database feature classLines
Data typeField nameAllow nulls
OBJECTID Object ID SHAPE Geometry YesJoined Short integer No
ParcelID Long integer NoSequence Long integer YesFromPoint Long integer No
ToPoint Long integer NoBearing Double YesDistance Double YesLineType Short integer NoRadius Double Yes
ArcDistance Double YesDelta Double Yes
CenterPoint Long integer YesHistorical Short integer No
SHAPE_Length Double YesRadialBearing Double Yes
TangentBearing Double YesEntryParameters Short integer No
AccuracyID Long integer Yes
Relationship class
One to many
Lines_Points
Lines have Lines have geometrygeometry defined by defined by dimensionsdimensions and by and by pointspoints
Model of a ParcelModel of a Parcel
Points & Control PointsPoints & Control Points
Survey Database feature classPoints
Data typeField nameAllow nulls
OBJECTID Object ID SHAPE Geometry YesJoined Short integer No
PointCode String YesPointName String YesHistorical Short integer NoRemarks String Yes
Contourable Short integer NoSystemStartDate Date YesSystemEndDate Date YesLegalStartDate Date YesLegalEndDate Date Yes
Survey Database feature classControlPoints
Data typeField nameAllow nulls
OBJECTID Object ID SHAPE Geometry Yes
X Double YesY Double YesZ Double Yes
Name String NoPointID Long integer Yes
AccuracyXY Double YesAccuracyZ Double Yes
CreatedDate Date YesActive Short integer Yes
GridFactor Double YesPointType Short integer No
Relationship class
One to One
Points_ControlPoints
A A control pointcontrol point is an special type of is an special type of parcel parcel pointpoint, giving that point an , giving that point an enhanced statusenhanced status
PlansPlans
Plans are used to represent a collection of Plans are used to represent a collection of information about a legal land documentinformation about a legal land document
Survey Database TablePlans
Data typeField nameAllow nulls
OBJECTID Object ID PlanName String No
AngularUnits Short integer YesDistanceUnits Short integer Yes
Surveyor String YesCompany String Yes
SurveyDate String YesModificationDate Date Yes
CoordinateSystem String YesStatus Short integer No
Coded value domainPlan StatusDescription
Field typeSplit policy
Merge policy
Status of the PlanShort integerDefault valueDefault value
DescriptionCode
0 0 - Tentative
1 1 - Provisional
2 2 - Approved
3 3 - Registered
Plans - ConceptsPlans - Concepts Most Parcels are associated with a Most Parcels are associated with a planplan
andand Jobs are often based on PlansJobs are often based on Plans Plans and all associated parcels can be Plans and all associated parcels can be
recovered from the Cadastral Fabric recovered from the Cadastral Fabric Plans hold the metadata for parcels (go Plans hold the metadata for parcels (go
back to legal document of origin)back to legal document of origin) You can extend the Plan concept to fit You can extend the Plan concept to fit
your organization, for example:your organization, for example: you can add to the schema for other sorts of you can add to the schema for other sorts of
metadata about the documentmetadata about the document
Data ModelData Model
Plans ModelPlans ModelSurvey Database TablePlans
Data typeField nameAllow nulls
OBJECTID Object ID PlanName String No
AngularUnits Short integer YesDistanceUnits Short integer Yes
Surveyor String YesCompany String Yes
SurveyDate String YesModificationDate Date Yes
CoordinateSystem String YesStatus Short integer No
Coded value domainPlan StatusDescription
Field typeSplit policy
Merge policy
Status of the PlanShort integerDefault valueDefault value
DescriptionCode
0 0 - Tentative
1 1 - Provisional
2 2 - Approved
3 3 - Registered
Survey Database feature class
Data typeField nameAllow nulls
OBJECTID Object ID SHAPE Geometry YesJoined Short integer No
ParcelName String NoPlanID Long integer No
ParcelType Short integer NoStatedArea Double YesCompiled Short integer No
TrueMidBrg Short integer NoHistorical Short integer No
SytemStartDate Date NoSystemEndDate Date NoLegalStartDate Date YesLegalEndDate Date Yes
SHAPE_Length Double YesSHAPE_Area Double Yes
CentroidX Double YesCentroidY Double Yes
AccuracyID Long integer No
Parcels
Relationship class
One to many
Plan_Parcel
Status manages the life-cycle of the Plan
History - ConceptsHistory - Concepts Parcels updated with new record information Parcels updated with new record information
are never deleted from the Fabric, they are are never deleted from the Fabric, they are simply marked as Historicsimply marked as Historic
4 different types of historic information 4 different types of historic information maintained:maintained: State of the Cadastre on a particular date State of the Cadastre on a particular date State of the Fabric on a particular date State of the Fabric on a particular date Lineage of a Lineage of a ParcelParcel History of Adjustments to the Cadastral History of Adjustments to the Cadastral
FabricFabric
1 2 36 644
2 74
1985 1994 2000
CustomisationCustomisation
This can start with adding new attributes This can start with adding new attributes (fields) to the Cadastral Fabric Tables(fields) to the Cadastral Fabric Tables
The Cadastral Editor can be used to edit The Cadastral Editor can be used to edit these attributes via the Property these attributes via the Property InspectorInspector
The Cadastral Editor UI is written using The Cadastral Editor UI is written using ArcObjects components, overlying an ArcObjects components, overlying an editing engineediting engine
WorkflowWorkflow
System IntegrationSystem Integration
Cadastral fabric tables can have Cadastral fabric tables can have relationships to other geodatabase tables relationships to other geodatabase tables via relationship classesvia relationship classes
So other systems, like a text based title So other systems, like a text based title management database, can be linked to management database, can be linked to the cadastral geometry of the fabricthe cadastral geometry of the fabric
WorkflowWorkflow
Editing WorkflowEditing Workflow
CadastralFabric
CreateJob
Select Parcels
StartEditing
AdjustSave orCommit
Lock
WorkflowWorkflow
Jobs – “Work-Orders”Jobs – “Work-Orders” A Job is a “A Job is a “work-orderwork-order” for creating, ” for creating,
modifying or adjusting one or more modifying or adjusting one or more parcels. For instance:parcels. For instance:Entering a parcel subdivisionEntering a parcel subdivisionEntering control pointsEntering control pointsAdjustmentAdjustment
WorkflowWorkflow
Survey Database TableJob
Data typeField nameAllow nulls
OBJECTID Object ID Name String No
Description String YesLocked Short integer No
LockedDate Date NoUpdateDate Date Yes
Jobs can be Jobs can be savedsaved, or , or committedcommitted Jobs can be open for any length of time Jobs can be open for any length of time
Locked ParcelsLocked Parcels A job may lock parcels, no other job can edit A job may lock parcels, no other job can edit
the parcel attributes or dimensionsthe parcel attributes or dimensions Parcel Points are never lockedParcel Points are never locked This allows LSA adjustment while jobs are This allows LSA adjustment while jobs are
openopen If not locked, standard reconcile will detect If not locked, standard reconcile will detect
conflictsconflicts
Survey Database TableJob
Data typeField nameAllow nulls
OBJECTID Object ID Name String No
Description String YesLocked Short integer No
LockedDate Date NoUpdateDate Date Yes
Relationship class
One to many
JobLockIDs_Jobs
TableJobLockIDs
Data typeField nameAllow nulls
OBJECTID Object ID JobID Long integer No
ObjectType Short integer NoOIDLock Long integer No
LockMethod Long integer Yes
Data ModelData Model
Parcel EditingParcel Editing The ‘unit of work’The ‘unit of work’ Parcels are created Parcels are created
by entering a loop by entering a loop traverse of the traverse of the parcel boundaryparcel boundary
Parcel closureParcel closure report is a report is a first level first level Q/A checkQ/A check
WorkflowWorkflow
First Level QA check
Parcel Join - ConceptsParcel Join - Concepts
Parcel Joining Parcel Joining enforcesenforces the the topologicaltopological model relationshipsmodel relationships between parcels between parcels
Join is an interactive ‘point and click’ UIJoin is an interactive ‘point and click’ UIMatch shared pointsMatch shared pointsAutomatic scale and rotate Automatic scale and rotate Auto-join utilityAuto-join utility
Second level QA checkSecond level QA check provided by the provided by the transformation residuals during a jointransformation residuals during a join
WorkflowWorkflow
Parcel JoinParcel Join
Second Level QA check
JoinJoin Joining is the easiest and fastest way to Joining is the easiest and fastest way to
build the Fabricbuild the Fabric Join process ensures fit to the FabricJoin process ensures fit to the Fabric
No slivers possibleNo slivers possible No accidental overlapsNo accidental overlaps Automatically handles translation, scale, Automatically handles translation, scale,
rotation from local reference systemrotation from local reference system
Each newly joined parcel adds valuable Each newly joined parcel adds valuable information that can be used in future information that can be used in future least squares adjustment jobsleast squares adjustment jobs
Least Squares AdjustmentLeast Squares Adjustment
Fabric + Control +LSA = Good CoordinatesFabric + Control +LSA = Good Coordinates Preparation of the data is half the workPreparation of the data is half the work
The fabric model and the software does thisThe fabric model and the software does this LSA does more than improve the LSA does more than improve the
coordinatescoordinates Shows where control is neededShows where control is needed Finds errors in the data (eg. incorrectly entered Finds errors in the data (eg. incorrectly entered
measurements…)measurements…) Extensive Reports on analysis of the dataExtensive Reports on analysis of the data
Works Works only on the coordinatesonly on the coordinates, never , never changes the original measurement valueschanges the original measurement values
Job AdjustmentJob Adjustment Once the Control Once the Control
has been tested, has been tested, job adjustment is job adjustment is easyeasy
Set tolerancesSet tolerances Select Select
constraintsconstraintsStraight linesStraight linesLine pointsLine points
WorkflowWorkflow
Job Commit (close-out)Job Commit (close-out) Before a change is inserted into the Before a change is inserted into the
Cadastral Fabric the system does Cadastral Fabric the system does integrity checks :integrity checks : Tests of bounding parcel coordinates Tests of bounding parcel coordinates Notify if need to readjustNotify if need to readjust If parcels were not locked, then reconcileIf parcels were not locked, then reconcile
On commit, the system:On commit, the system: Calculates adjustment vectorsCalculates adjustment vectors Updates job, history…Updates job, history… Releases locks on the parcelsReleases locks on the parcels
WorkflowWorkflow
Associated Feature ClassesAssociated Feature Classes On commit, the transaction manager On commit, the transaction manager
creates a set of Adjustment Vectorscreates a set of Adjustment Vectors Each point’s coordinate residual provides a Each point’s coordinate residual provides a
vector that may be used on the GIS layersvector that may be used on the GIS layers Vector sets are stored as a history of Vector sets are stored as a history of
coordinate shifts based on each least sq. coordinate shifts based on each least sq. adjustmentadjustment
GIS Layers can be updated using the GIS Layers can be updated using the Adjustment VectorsAdjustment Vectors You decide when to make a GIS layer update You decide when to make a GIS layer update
to the Cadastral Fabricto the Cadastral Fabric This is possible because Cadastral Fabric This is possible because Cadastral Fabric
maintains the adjustment “history” of each maintains the adjustment “history” of each layerlayer
WorkflowWorkflow
GIS Layers AdjustmentGIS Layers AdjustmentWorkflowWorkflow
GIS Layers AdjustmentGIS Layers AdjustmentWorkflowWorkflow
SUMMARYSUMMARY
ArcGIS has been extended for cadastre dataArcGIS has been extended for cadastre data Improve existing data, regardless of qualityImprove existing data, regardless of quality It uses survey methodsIt uses survey methods Can follow a job workflow, and keep historyCan follow a job workflow, and keep history Applies cadastral adjustments to feature Applies cadastral adjustments to feature
classesclasses Is an easily extended and customized systemIs an easily extended and customized system It supports ‘remote’ editingIt supports ‘remote’ editing It supports pessimistic lockingIt supports pessimistic locking Can be scaled to very large datasetsCan be scaled to very large datasets