Transcript Slajd 1

State geodetic administration (SGA), Croatia
From vector cadastral plan to
Object-oriented database
Presenter: Branka Vorel
www.dgu.hr
CROATIA SGA – general
SGA head office + Regional Cadastral Offices (20) and Branch Offices (92)
City Office for Cadastre and Geodetic Activities (Zagreb)
Land area is approximately 57,000 km ²
Cadastral parcels apx. 14,166,142
3307 C.M.
From vector cadastral plan to Object-oriented database
Challenge for CRO Cadastre in Digital Era
From vector cadastral plan to Object-oriented database
PROBLEMS ?
From vector cadastral plan to Object-oriented database
Cadastral plans main problems – graphical plans
From vector cadastral plan to Object-oriented database
Cadastral plans main problems - inhomogeneous
Weight inversely proportional to the distance
From vector cadastral plan to Object-oriented database
Statistics of maintening cadastral plans
CAD/vector format = 2219 c.m.
No standardization
No history of changes
Store on local cadastre databeses
No automatic procedure for exchange
GIS = 1088 c.m.
Central database
Overnight replica in head office SGA
Services to other users
Simple precedures for exchange data
From vector cadastral plan to Object-oriented database
QK#1
New projection
QK#2
SGA HO +
Cadastre
Standardization
SGA HO
Exchange/migration format
Import in database
7/6/2015
8
Data verification
Standardization and QK
SGA prescribed structure of vector plans maintained with CAD tools through Specification.
Almost 60% of cadastral offices don´t maintain cadastral plans in accordance with the
Specification.
What does it mean?
Content of the plan: topographic /symbolic-> standardized
Centorids: hatch-> code
Centroid position: outside polygon-> inside polygon
Centroid format : text, mtext -> block
Geometry of objects: pline, spline, multyline -> line
Centroid domain: descriptive code, outside the domain -> code in accordance with the
Specification
From vector cadastral plan to Object-oriented database
Standardization and QK – activities
Topology problems:
Duplicate line, zero lenght line, trim and extende problems, object whit
duplicate or no centorids, object whit wrong object centorid, wrong angle
definition in CAD, 9 decimal problems
Activities:
We developing procedures for quality control according to the SGA
Specifications – FME WB and desktop app
After initial Standardisation and QK cadastre office will have obligation at
least once a month to control plans and submit a report of QC to HO SGA.
From vector cadastral plan to Object-oriented database
Exchanhe/migration format (1)
From vector cadastral plan to Object-oriented databese
Exchanhe/migration format (2) – key issues
a) Decimal places CAD 9 d.p. -> GIS 2 d.p. (Oracle database on centimeter accuracy )
Before QC#1: DWG/DXF out and round coordinates on 2 decimale place!!!
b) Define GML scheme and SHP layers
Relations between objects, attributes and geometry
Formats of attributes
Range of domains of attributes
Geometry of specific objects (multypoligons)
<!-- aggregate geometry elements -->
<element name="MultiPolygon" type="gml:MultiPolygonType"substitutionGroup="gml:_Geometry"/>
c) FME WB standardized procedures for transforming DWG/DXF format to SHP / GML format
d) FME WB procedures for QC of SHP / GML fromat before import in database
From vector cadastral plan to Object-oriented database
New projection
From vector cadastral plan to Object-oriented database
QK#2 – before import to database
This is a control that depends on the specific requirements of the database in
which the data is migrated.
This is process of profiling the data to discover topology and atribute
inconsistencies and conflicts not only in the individual SHP or GML layers, but
also in their mutual relations.
From vector cadastral plan to Object-oriented database
Data verification in cadstre office
This is necessary in case of data migration in GIS application for
maintenance cadastral plans.
Current situation:
After migration there is usualy 2 week testing phase.
Cadastral office-workers due to lack of time, do not pay attention to
special cases - errors are notice in the full production.
Cadastral office-workers were not trained to verify the quality of
migrated data.
Planned activities:
a) prepare detailed instructions for the verification procedure and test
cases with regard to the specifics of each cadastral office
b) prior to verification - workshop with staff
From vector cadastral plan to Object-oriented database
Final thoughts…
WIKI: Interoperability is the ability of diverse systems and
organizations to work together (inter-operate).
The way I see it:
Constantly updating and collecting data
Mutually exchange data/informations
Linking data from various sources/holders
Think reversible
Think globally
From vector cadastral plan to Object-oriented database
Thank you for your attention !
[email protected]