Transcript Survey Accurate Cadastral Project for Sutherland Council

CADASTRAL UPGRADE PROJECTS
for
LOCAL GOVERNMENT
A Possible Upgrade Path
© Geodata Australia
Geodata Process
The Geodata process using
software developed by Michael Elfick with Mike
Fletcher and Mimaka Pty Ltd and now
represented by Geodata allows the creation of a
coordinated digital cadastral database from
original survey data thus preserving the
mathematical integrity of the original survey
observations
© Geodata Australia
It is Unique
 The traditional method for surveying land is to
measure a precise control network and then use
this to fix the position of the land parcel.
 Geodata has followed the Elfick approach and
adopted the inverse of this concept in that the
land parcels are captured, joined and assembled
and then analyzed to determine the amount and
location of the control required.
© Geodata Australia
The Background
 The process was developed as a result of
investigations and a trial conducted by the NSW Lands
Department together with the Association of
Consulting Surveyors and University of Newcastle to
determine whether a reasonable and cost effective
alternative existed to creating a DCDB from digitised
topographical maps.
 The decision was taken following the investigations to
implement proposals to digitise topographical maps.
 Michael Elfick continued developing his cadastral
software – CADP in the belief that it presented a better
Cadastral Database
© Geodata Australia
The Background
 CADP as the program was then known has been
used to create and manage the NCDB in the ACT
and the NT (NCDB is used to differentiate
between the spatially accurate Geodata cadastre
from the DCDB derived from digitised
topographical maps.
 CADP has also been used in NZ, USA and The
Philippines for cadastral management projects
and has been successfully trialed and
demonstrated in a number of Australian
jurisdictions CADP has been licensed to Geodata
and renamed GeoCadastre
© Geodata Australia
The ESRI Connection
 Geodata and ESRI have worked collaboratively to
incorporate GeoCadastre into ArcMap as an
extension to Survey Analyst which will be released
to international markets circa Q1 2007, in ArcGIS
9.2
 The Survey Analyst 9.2 will allow the storage of
cadastral data in a geodatabase without any loss of
mathematical integrity to the survey data.
 SurveyXML™ has been jointly developed with ESRI
as an interchange format to transport cadastral
data to the geodatabase.
© Geodata Australia
The ESRI Model for Application of
GeoCadastre within Survey Analyst
Maps, Plats
Field Books
Survey Data
(measurements)
Other survey
and engineering
file formats
Field
Measurements
Geodatabase
Applications
Imagery
- Data automation
and maintenance
- GIS analysis
- Enterprise
mapping
requirements
- Land records
GIS data
CAD data
Text and Paper
Documents
- Surveys Information
System
- Measurement-based
Cadastre
© Geodata Australia
Step by Step Geodata Approach
to Cadastral Upgrade
Step 1 –
Step 2 –
Step 3 –
Step 4 –
Step 5 –
Step 6 –
Step 7 –
Collate source Deposited Plans and machine
readable survey data
Capture and convert source data – data entry
from survey plans and or electronic files
Identify irregularities and misclose
Rectify errors
Incorporate base cadastre with client GIS
systems
Move Asset Layers to the Accurate Cadastre
Consult on maintenance of cadastral dataset
© Geodata Australia
Survey
Built Environment
Data Delivery
to Clients
Record
Web Delivery
Possible
GeoCadastre Process
N
C
D
B
Survey Plans
Data Entry
Parcels Joined
& Assembled
Fabric Adjusted
© Geodata Australia
GRAPHICAL
INFORMATION
SYSTEM
LAYERS
ENGINEERING
SURVEY
CADASTRAL
FABRIC
CONTROL
SURVEY
Conversion Stage 1 - Parcel
Data Entry
 Keyboard operation
 Screen will display the lines as they are entered
 Enter bearings distances and areas – in the plan
units of measurement : calculation of close and
accuracy applied by the software
 Supervisor would check errors on regular basis
and rectify as needed
© Geodata Australia
Conversion Stage 1 - Parcel
Data Entry
As parcel
data is
entered
from the
keyboard
the
drawing
appears
on screen
© Geodata Australia
Conversion Stage 2 - Parcel
Joining
 Achieved by mouse operation
 Parcels joined together by clicking on matching
points
 Operator checks rotation and scale precision and
notes errors for supervisor rectification
© Geodata Australia
Conversion Stage 2 Parcel Joining
Parcel to be
joined to the
fabric is
selected
and
common
points of
connection
are selected
Common points on the parcel and the
existing fabric are selected
Joining – Check scale, then type ‘y’.
© Geodata Australia
Common Points Selected & Parcel is
Added into the Cadastral Fabric
The joined
parcel is
added to
the fabric
and now
appears in
the parcel
explorer
window as
joined
© Geodata Australia
Conversion Stage 3
Adjustment & Assembly
 Select known co-ordinate control points to
adjust an area
 Choose geodetic system, zone and acceptable
tolerance for the adjustment based on
precision of survey plans
 Run the co-ordinate adjustment process
© Geodata Australia
Conversion Stage 3 – Co-ordinate
Adjustment
Tolerances set
Listing file
location
nominated
Adjustment
summary
detailed
© Geodata Australia
Cadastre – Display Parameters
Easements
Roads and
Parcel Lines
are shown in
different
colours and
various
display
parameters
can be turned
on and off
© Geodata Australia
Plan Shaded to Show Plan
Accuracies
© Geodata Australia
The Outcome
 A complete parcel network;
 A correct cadastral dataset;
 Co-ordinate precision
 The cadastral base layer for GIS
© Geodata Australia
Zoom Window of DCDB (Blue) Overlaid on NCDB
(Red)
© Geodata Australia
Differences between NCDB and
DCDB
Gross
error
here of
101.6m
but
typically
in this
dataset
the
errors
are circa
8 metres
© Geodata Australia
Benefits of an NCDB
1. Complete, correct and precise position based
cadastre
2. One common cadastre for all users
3. Elimination of duplication
4. Reduced delays for update
5. Provisional layer for planning purposes is possible
6. Unification of GIS with GPS
7. Interchangeable datasets between users
8. Reduction in labour intensive GIS conversions
© Geodata Australia
Alternative – Gradual Upgrade
 The cost of re-building a cadastre to NCDB
standards from scratch is often greater than
Councils are prepared and able to meet.
 Geodata is able to assist in the alternative
process of gradual upgrade to numeric
standards
© Geodata Australia
Progressive Upgrade
 Using the existing DCDB as a base, accurate
cadastral data can be prepared using
GeoCadastre and inserted into the DCDB.
 The DCDB for an area is first brought into
GeoCadastre through GeoSurvey.
 The following is the Gloucester DCDB on
which Geodata is currently working
© Geodata Australia
Area 5 within the DCDB
© Geodata Australia
Progressive Upgrade
 Area 5 comprises some parcels for which
reasonable plans are available but the balance
is an area comprising old system titles where
reasonable survey data is not immediately
available
 Area 5 is exported from MapInfo (the format the
DCDB was received in) but could as easily done
from ArcMap for import to GeoSurvey
© Geodata Australia
Area 5
Export
from
MapInfo
(or ESRI
ArcMap)
© Geodata Australia
Converting Strings to Parcels in
GeoSurvey
Inversing
the DCDB
parcels
© Geodata Australia
Area 5 in GeoCadastre
The DCDB
Converted to
GeoCadastre
format
© Geodata Australia
Adjustment of Area 5
Control is
applied
and the
cadastre
adjusted
without
any
attempt
to
improve
accuracy
© Geodata Australia
Accurate data to be appended
Cadastral
data
recorded in
GeoCadast
re from
survey
plans
© Geodata Australia
Unjoining parcels ready for
appending
Parcels
comprising
the accurate
data are
unjoined from
the DCDB
dataset
© Geodata Australia
Appending accurate data
The survey
accurate
GeoCadast
re dataset
is
appended
and joined
to the
DCDB
© Geodata Australia
Accurate data joined with digitised
DCDB
© Geodata Australia
Whole Dataset Shaded to Show
Relative Accuracy (Age of Plans)
Weighting of data
in the adjustment
process is reflected
in age of plans.
Digitized DCDB is
Orange
© Geodata Australia
Progressive Upgrade
 It can be seen from the last group of slides how
a progressive update of cadastral data can be
achieved using Geodata software and process
 The process can be dictated and controlled by
Council to it’s own timetable and requirements
 Relatively unskilled (in Survey of GIS
disciplines) personnel can be used for this
process
© Geodata Australia
Progressive Upgrade
 To enable a Council to proceed immediately
with a progressive update of it’s cadastre it
would need to purchase at least one seat each
of GeoCadastre and GeoSurvey
 The cost of GeoCadastre and GeoSurvey is
$3,750 each per seat plus annual maintenance
(optional) of $500 each which carries with it
free technical support and upgrades.
 Discounts are available for multiple purchases.
© Geodata Australia
Progressive Upgrade
 Geodata is also able to offer consultancy
services on cadastral upgrade and
management
 Consultancy services are available from
Geodata at negotiated per diem rates
© Geodata Australia
Inquiries:
 Roger Lee
Address:
P.O. Box 574
East Maitland
N.S.W. 2323.
 Email: [email protected]
 Tel:
02 4922 5088
 Fax:
02 4964 4789
 Mobile:
0407 333 078
© Geodata Australia