ICA Workshop on Geospatial Analysis and Modeling 8 July 2006 Vienna

ICA Workshop on Geospatial Analysis and Modeling 8 July 2006 Vienna

A TOOL PERFORMING TOPOLOGICAL CORRECTION

IN GIS

A TOOL PERFORMING TOPOLOGICAL CORRECTION

IN GIS

Stefano BellesiStefano Bellesi - Regione Marche - Ancona (Italy) stefano.bellesi@regione.marche.it

Eva Savina MalinverniEva Savina Malinverni - Università Politecnica delle Marche - Ancona (Italy) e.s.malinverni@univpm.it

GENERALITYGENERALITY

THE GIS DATA STRUCTURETHE GIS DATA STRUCTURE

THE DATA MAINTENANCETHE DATA MAINTENANCE

APPLICATIONSAPPLICATIONS

TOPICSTOPICSTOPICSTOPICS

ANALYSIS OF THE TOPOLOGICAL ANALYSIS OF THE TOPOLOGICAL INCONSISTENCY IN SPATIAL INCONSISTENCY IN SPATIAL DATABASES COMING FROM DATABASES COMING FROM NUMERICAL CARTOGRAPHY NUMERICAL CARTOGRAPHY

ORGANIZED IN INFORMATIVE LAYERSORGANIZED IN INFORMATIVE LAYERS

ANALYSIS OF THE TOPOLOGICAL ANALYSIS OF THE TOPOLOGICAL INCONSISTENCY IN SPATIAL INCONSISTENCY IN SPATIAL DATABASES COMING FROM DATABASES COMING FROM NUMERICAL CARTOGRAPHY NUMERICAL CARTOGRAPHY

ORGANIZED IN INFORMATIVE LAYERSORGANIZED IN INFORMATIVE LAYERS

GENERALIZATION IN THE GIS GENERALIZATION IN THE GIS PRESERVING THE PRESERVING THE

CORRESPONDENCES AND THE CORRESPONDENCES AND THE DATA STRUCTURESDATA STRUCTURES

GENERALIZATION IN THE GIS GENERALIZATION IN THE GIS PRESERVING THE PRESERVING THE

CORRESPONDENCES AND THE CORRESPONDENCES AND THE DATA STRUCTURESDATA STRUCTURES

IMPLEMENTATION OF A NEW TOOL “IMPLEMENTATION OF A NEW TOOL “TOPOLOGY TOPOLOGY ”” IN A COMMERCIAL IN A COMMERCIAL SOFTWARE TO SOLVE SOME TOPOLOGICAL PROBLEMSSOFTWARE TO SOLVE SOME TOPOLOGICAL PROBLEMS

IMPLEMENTATION OF A NEW TOOL “IMPLEMENTATION OF A NEW TOOL “TOPOLOGY TOPOLOGY ”” IN A COMMERCIAL IN A COMMERCIAL SOFTWARE TO SOLVE SOME TOPOLOGICAL PROBLEMSSOFTWARE TO SOLVE SOME TOPOLOGICAL PROBLEMS

TYPOLOGIES OF DATA STRUCTURESTYPOLOGIES OF DATA STRUCTURESTYPOLOGIES OF DATA STRUCTURESTYPOLOGIES OF DATA STRUCTURES

VECTOR MODEL: objects which have a position in the space (2D-3D)

TOPOLOGY: spatial relationships among the objects (2D)

ATTRIBUTE: the description of the objects

……the spatial relations, typically derived from positional information, are often imprecise and they can produce some results in conflict with the geometric representation of the real objects…...

……the spatial relations, typically derived from positional information, are often imprecise and they can produce some results in conflict with the geometric representation of the real objects…...

HoweverHowever

““NONNON -TOPOLOGICAL” MODEL -TOPOLOGICAL” MODEL

The vector model is the most natural The vector model is the most natural computer graphic translation of real computer graphic translation of real objectsobjects Every object is represented by a Every object is represented by a single entitysingle entityEvery entity is represented by a single Every entity is represented by a single primitiveprimitiveIt is possible to have duplicated It is possible to have duplicated primitivesprimitives

VECTOR MODELVECTOR MODELVECTOR MODELVECTOR MODEL

RedundanciesRedundancies IncongruitiesIncongruities

Disadvantages:

in the sense that object-face relationships are not preserved

in the sense that object-face relationships are not preserved

• There are not primitives There are not primitives parzially or totally overlappedparzially or totally overlapped

•It needs to divide the entities It needs to divide the entities according to the primitivesaccording to the primitives

• Different entities can share the Different entities can share the same primitivessame primitives

•This type of data manipulation This type of data manipulation involves concepts such as involves concepts such as adjacency, connectivity and adjacency, connectivity and containmentcontainment

The topological model repeats the traditional drawing in cartography

The topological model repeats the traditional drawing in cartography

Advantages:

THE SPATIAL RELATIONSHIPS PLAY AN IMPORTANT ROLE IN THE THE SPATIAL RELATIONSHIPS PLAY AN IMPORTANT ROLE IN THE SPATIAL DATABASE, SINCE THEY ARE USUALLY THE BASE FOR A SPATIAL DATABASE, SINCE THEY ARE USUALLY THE BASE FOR A CORRECT USE OF THE QUERIESCORRECT USE OF THE QUERIES

THE SPATIAL RELATIONSHIPS PLAY AN IMPORTANT ROLE IN THE THE SPATIAL RELATIONSHIPS PLAY AN IMPORTANT ROLE IN THE SPATIAL DATABASE, SINCE THEY ARE USUALLY THE BASE FOR A SPATIAL DATABASE, SINCE THEY ARE USUALLY THE BASE FOR A CORRECT USE OF THE QUERIESCORRECT USE OF THE QUERIES

TOPOLOGICAL MODELTOPOLOGICAL MODELTOPOLOGICAL MODELTOPOLOGICAL MODEL

A TOPOLOGICAL MODEL CAN BE A TOPOLOGICAL MODEL CAN BE

UNDERSTOOD AS A PLANAR NETWORK UNDERSTOOD AS A PLANAR NETWORK

THAT DEFINES THE CONNECTION WITH THE THAT DEFINES THE CONNECTION WITH THE

FOLLOWING PRIMITIVESFOLLOWING PRIMITIVES

nodesnodes arcsarcs polygonpolygonss

DATA MAINTENANCE REQUIREMENTSDATA MAINTENANCE REQUIREMENTSDATA MAINTENANCE REQUIREMENTSDATA MAINTENANCE REQUIREMENTS

TO MAINTAIN RELATIONSHIPS BETWEEN THE PRIMITIVESTO MAINTAIN RELATIONSHIPS BETWEEN THE PRIMITIVES

TO USE TOPOLOGICAL RELATIONS TO DETECT AND CORRECT ERRORS IN GIS DATA SETS

TO USE TOPOLOGICAL RELATIONS TO DETECT AND CORRECT ERRORS IN GIS DATA SETS

Spatial relations are typically derived by data manipulation such Spatial relations are typically derived by data manipulation such that the check of the topological inconsistency involves not only that the check of the topological inconsistency involves not only

the control of the stored data, but also the control of the data the control of the stored data, but also the control of the data manipulation resultsmanipulation results

Spatial relations are typically derived by data manipulation such Spatial relations are typically derived by data manipulation such that the check of the topological inconsistency involves not only that the check of the topological inconsistency involves not only

the control of the stored data, but also the control of the data the control of the stored data, but also the control of the data manipulation resultsmanipulation results

TOPOLOGICAL CORRECTION APPROACHTOPOLOGICAL CORRECTION APPROACHTOPOLOGICAL CORRECTION APPROACHTOPOLOGICAL CORRECTION APPROACH

A COMPLETE APPROACH REQUIRES THREE DIFFERENT TASKS:

THE DEFINITION OF THE ERRORSTHE DEFINITION OF THE ERRORS

THE CHECK OF THE DATABASETHE CHECK OF THE DATABASE

THE CORRECTION OF THE ERRORSTHE CORRECTION OF THE ERRORS

A COMPLETE APPROACH REQUIRES THREE DIFFERENT TASKS:

THE DEFINITION OF THE ERRORSTHE DEFINITION OF THE ERRORS

THE CHECK OF THE DATABASETHE CHECK OF THE DATABASE

THE CORRECTION OF THE ERRORSTHE CORRECTION OF THE ERRORS

Since an error is defined as a forbidden topological relation between the objects, the way to correct it will be to create the

correct topological relationships between these objects

Since an error is defined as a forbidden topological relation between the objects, the way to correct it will be to create the

correct topological relationships between these objects

•Data qualityData quality

•Computational geometryComputational geometry

THE MOST FREQUENT PROBLEMS WHICH CAN HAPPEN ARE: THE MOST FREQUENT PROBLEMS WHICH CAN HAPPEN ARE:

Why topology is Why topology is so important?so important?

Why topology is Why topology is so important?so important?

TOPOLOGICAL INCONSISTENCYTOPOLOGICAL INCONSISTENCYTOPOLOGICAL INCONSISTENCYTOPOLOGICAL INCONSISTENCY

double and redundant verticesdouble and redundant vertices

overlapped arcsoverlapped arcs

double and tangent arcsdouble and tangent arcs

missed tangency between two arcsmissed tangency between two arcs

double and redundant verticesdouble and redundant vertices

overlapped arcsoverlapped arcs

double and tangent arcsdouble and tangent arcs

missed tangency between two arcsmissed tangency between two arcs

TOPOLOGICAL CHECKTOPOLOGICAL CHECKTOPOLOGICAL CHECKTOPOLOGICAL CHECK

If the datum is already topologically consistent it is possible to create, without mistakes, the topological structure before to verify the correctness of the data from a geometric point of view and successively to create the topological relationships

If the datum is already topologically consistent it is possible to create, without mistakes, the topological structure before to verify the correctness of the data from a geometric point of view and successively to create the topological relationships

SOME TOPOLOGICAL CONTROLS ARE SOME TOPOLOGICAL CONTROLS ARE APPLICABLE TO MONO-DIMENSIONAL APPLICABLE TO MONO-DIMENSIONAL

ELEMENTSELEMENTS

SOME TOPOLOGICAL CONTROLS ARE SOME TOPOLOGICAL CONTROLS ARE APPLICABLE TO MONO-DIMENSIONAL APPLICABLE TO MONO-DIMENSIONAL

ELEMENTSELEMENTS

MAPINFO PROFESSIONAL 7.5MAPINFO PROFESSIONAL 7.5

MAPBASIC 7.0MAPBASIC 7.0

MAPINFO PROFESSIONAL 7.5MAPINFO PROFESSIONAL 7.5

MAPBASIC 7.0MAPBASIC 7.0

A TOPOLOGICAL CORRECTION TOOLA TOPOLOGICAL CORRECTION TOOLA TOPOLOGICAL CORRECTION TOOLA TOPOLOGICAL CORRECTION TOOL

Some commercial GIS software have some evident gaps Some commercial GIS software have some evident gaps performing a topological investigationperforming a topological investigation

Some commercial GIS software have some evident gaps Some commercial GIS software have some evident gaps performing a topological investigationperforming a topological investigation

These software do not deal with topological relations or consider only few relations so that the correction tools do not always work in an automatic way

but sometimes require the support of an human operator

These software do not deal with topological relations or consider only few relations so that the correction tools do not always work in an automatic way

but sometimes require the support of an human operator

How to create a correct How to create a correct topological model?topological model?

Message Windows

Menu Toolbar

THE VISUAL INTERFACE FOR END-USERSTHE VISUAL INTERFACE FOR END-USERSTHE VISUAL INTERFACE FOR END-USERSTHE VISUAL INTERFACE FOR END-USERS

To help and inform about the performancesTo help and inform about the performances

To choice the type of topological checksTo choice the type of topological checks

MANY SUBROUTINES PERFORM SPECIFIC TASKSMANY SUBROUTINES PERFORM SPECIFIC TASKS

THE SOFTWARE THE SOFTWARE TOPOLOGYTOPOLOGYTHE SOFTWARE THE SOFTWARE TOPOLOGYTOPOLOGY

THE APPLICATION TO A CADASTRAL MAPTHE APPLICATION TO A CADASTRAL MAPTHE APPLICATION TO A CADASTRAL MAPTHE APPLICATION TO A CADASTRAL MAP

The first application regards the topological control and correction of a cadastral map related to Genga (Ancona – Italy) at the scale 1:2000

The first application regards the topological control and correction of a cadastral map related to Genga (Ancona – Italy) at the scale 1:2000

THE FIRST TASK CREATES THE TABLES TO PERFORM THE TOPOLOGICAL RELATIONSHIPS SUCCESSIVELY

Linear entity

Point entity

Region entity

THE DATA ORGANIZATIONTHE DATA ORGANIZATIONTHE DATA ORGANIZATIONTHE DATA ORGANIZATION

NODE ATTRIBUTE TABLENODE ATTRIBUTE TABLE

ARC ATTRIBUTE TABLEARC ATTRIBUTE TABLE

POLYGON ATTRIBUTE TABLEPOLYGON ATTRIBUTE TABLE

Subroutine ‘ Arctable’Subroutine ‘ Arctable’ Subroutine ‘ Arctable’Subroutine ‘ Arctable’

Sub Arctable

Create Table AAT

Create Table NAT

Create Map For AAT

Create Map For NATCommit Table AAT

Commit Table NAT

Alter menu

“ Table AAT and NAT”End Sub

prepares the data

prepares the data

Node Attribute Table (NAT)Node Attribute Table (NAT)

The Node Attribute The Node Attribute Table contains the Table contains the corresponding corresponding starting and ending starting and ending nodesnodes

The Node Attribute The Node Attribute Table contains the Table contains the corresponding corresponding starting and ending starting and ending nodesnodes

Arc Attribute Table (AAT)Arc Attribute Table (AAT)

The Arc Attribute Table The Arc Attribute Table organizes all the linear organizes all the linear entitiesentities

The Arc Attribute Table The Arc Attribute Table organizes all the linear organizes all the linear entitiesentities

Polygon Attribute Table (PAT)Polygon Attribute Table (PAT)

Polygon Attribute Table (PAT) Polygon Attribute Table (PAT) contains all the areas in the map contains all the areas in the map

identified by the coordinates of their identified by the coordinates of their own centroidown centroid

Polygon Attribute Table (PAT) Polygon Attribute Table (PAT) contains all the areas in the map contains all the areas in the map

identified by the coordinates of their identified by the coordinates of their own centroidown centroid

USE A CONTROL DISTANCE

Delete the double or redundant nodesDelete the double or redundant nodes

USE A COLINEARITY DISTANCE

Line up the polylinesLine up the polylines

A dedicated dialogue box in the software requires some parameters and a A dedicated dialogue box in the software requires some parameters and a window notifies the found errorswindow notifies the found errors

A dedicated dialogue box in the software requires some parameters and a A dedicated dialogue box in the software requires some parameters and a window notifies the found errorswindow notifies the found errors

MONO-DIMENSIONAL ENTITIES CHECKMONO-DIMENSIONAL ENTITIES CHECKMONO-DIMENSIONAL ENTITIES CHECKMONO-DIMENSIONAL ENTITIES CHECK

To recognize the overlapped polylines a buffer is traced around every linear element

To recognize the overlapped polylines a buffer is traced around every linear element

This verifies that any other polyline is not entirely contained in this area of control

The buffer value is choice by the end-user

OVERLAPPED OVERLAPPED POLYLINESPOLYLINES

The found overlapped entities can be:

٠ automatically deleted

٠ verified and manually deleted

٠ unchanged

A message window refershow many errors have been localized

Topological error correction

Node Attribute TableThe nodes are counted at least twice

٠ buffer around the node

٠ test of the presence of another node or polyline

٠ closure of the polylines

Buffer value based on the graphic error multiplied by the scale of the map

WARNING: if the buffer value is too small, the program requires another value

CHECK OF THE PERFECT CLOSURE IN CHECK OF THE PERFECT CLOSURE IN CORRESPONDENCE OF THE NODESCORRESPONDENCE OF THE NODES

Node of a polyline next to an arc

USE A CONTROL DISTANCEUSE A CONTROL DISTANCE

A way to correct such an error is to create an intersection point and to split the polyline in the tangent points

MISSED TANGENCYMISSED TANGENCY

REGION topological control

Bi-dimensional entities directly depend on the

mono-dimensional ones

If these entities do not contain topological errors also the areas are correct

Overlapped Areas

Test the adjacency of every area

The software automatically verifies the exixtence of the overlaps

The overlapped areas are highlighted and cut

Area containing holes inside

USE A THRESHOLD VALUE TO IDENTIFY THE HOLE

BI-DIMENSIONAL ENTITIES CHECKBI-DIMENSIONAL ENTITIES CHECKBI-DIMENSIONAL ENTITIES CHECKBI-DIMENSIONAL ENTITIES CHECK

The HOLE is filledThe HOLE is filledThe HOLE is filledThe HOLE is filled

SOME REMARKSSOME REMARKSSOME REMARKSSOME REMARKS

The use of the program has underlined two problems during The use of the program has underlined two problems during the correction phasesthe correction phases

The use of the program has underlined two problems during The use of the program has underlined two problems during the correction phasesthe correction phases

ONE REGARDS THE OPENED ARCS WITHOUT INTERSECTIONONE REGARDS THE OPENED ARCS WITHOUT INTERSECTIONONE REGARDS THE OPENED ARCS WITHOUT INTERSECTIONONE REGARDS THE OPENED ARCS WITHOUT INTERSECTION

They are not automatically removed, but the operator, examining the They are not automatically removed, but the operator, examining the map, decides to make some changes and the procedure can be iteratedmap, decides to make some changes and the procedure can be iterated

They are not automatically removed, but the operator, examining the They are not automatically removed, but the operator, examining the map, decides to make some changes and the procedure can be iteratedmap, decides to make some changes and the procedure can be iterated

SECOND ONE REGARDS THE CLOSURE OF ARCS IN SECOND ONE REGARDS THE CLOSURE OF ARCS IN CORRESPONDENCE OF THE NODESCORRESPONDENCE OF THE NODESSECOND ONE REGARDS THE CLOSURE OF ARCS IN SECOND ONE REGARDS THE CLOSURE OF ARCS IN CORRESPONDENCE OF THE NODESCORRESPONDENCE OF THE NODES

Where the control area value is too small to perform the closure, it is Where the control area value is too small to perform the closure, it is necessary to perform a manual correctionnecessary to perform a manual correction

Where the control area value is too small to perform the closure, it is Where the control area value is too small to perform the closure, it is necessary to perform a manual correctionnecessary to perform a manual correction

The aim of this other application regards the construction, representation and generalization in the GIS of different map

scales by standard procedure, preserving the correspondences and the data structures

The aim of this other application regards the construction, representation and generalization in the GIS of different map

scales by standard procedure, preserving the correspondences and the data structures

GENERALIZATION OF TECHNICAL MAPSGENERALIZATION OF TECHNICAL MAPS

AT DIFFERENT SCALESAT DIFFERENT SCALES

GENERALIZATION OF TECHNICAL MAPSGENERALIZATION OF TECHNICAL MAPS

AT DIFFERENT SCALESAT DIFFERENT SCALES

GENERALIZATION changes the representation of scale-dependent phenomena, eliminating redundant details and simplifying the appearance

and density of objects to improve the analysis capabilities

GENERALIZATION changes the representation of scale-dependent phenomena, eliminating redundant details and simplifying the appearance

and density of objects to improve the analysis capabilities

DB 1:10.000

DB 1:25.000

RESPECTRESPECTTOPOLOGICAL TOPOLOGICAL

RULESRULES

RESPECTRESPECTTOPOLOGICAL TOPOLOGICAL

RULESRULES

Topological consistency must be maintained both within individual features Topological consistency must be maintained both within individual features and among the co-displayed features for all the scales at which they may be and among the co-displayed features for all the scales at which they may be

retrievedretrieved

Topological consistency must be maintained both within individual features Topological consistency must be maintained both within individual features and among the co-displayed features for all the scales at which they may be and among the co-displayed features for all the scales at which they may be

retrievedretrieved

Marche Region Technical Maps at the scale 1:10.000 (DB10, year 1999)

IGMI new maps at the scale 1:25.000 (DB25, year 1993)

Marche Region Technical Maps at the scale 1:10.000 (DB10, year 1999)

IGMI new maps at the scale 1:25.000 (DB25, year 1993)

CASE OF STUDYCASE OF STUDYCASE OF STUDYCASE OF STUDY

LAYER : LAYER : ROADS AND RAILWAYSROADS AND RAILWAYSLAYER : LAYER : ROADS AND RAILWAYSROADS AND RAILWAYS

To derive from a correct data structure at the scale 1:10.000 a new valid geometric To derive from a correct data structure at the scale 1:10.000 a new valid geometric and topological data structure suitable to the scale 1:25.000 and topological data structure suitable to the scale 1:25.000

AN IMPORTANT REQUIREMENTAN IMPORTANT REQUIREMENTAN IMPORTANT REQUIREMENTAN IMPORTANT REQUIREMENT

List of all the features in the map organized by code, List of all the features in the map organized by code, description and geometric primitivesdescription and geometric primitives

List of all the features in the map organized by code, List of all the features in the map organized by code, description and geometric primitivesdescription and geometric primitives

ROAD NETWORK REPRESENTATION ROAD NETWORK REPRESENTATION

BY NODES AND ARCSBY NODES AND ARCS

ROAD NETWORK REPRESENTATION ROAD NETWORK REPRESENTATION

BY NODES AND ARCSBY NODES AND ARCS

In the DB25 there are much more classes than in the DB10 and different In the DB25 there are much more classes than in the DB10 and different types of symbolic representationstypes of symbolic representations

ROAD AND RAILWAY

DB 1:10.000

TOPOLOGICALTOPOLOGICAL RECONSTRUCTIONRECONSTRUCTION

TOPOLOGICALTOPOLOGICAL RECONSTRUCTIONRECONSTRUCTION

DB 1:25.000

POLYLINE FEATURES

POINT FEATURES

POLYGON FEATURES

POLYLINE FEATURES

POINT FEATURES

POLYGON FEATURES

POINT FEATURES

Verify network scheme by the specifications of

the map

Verify network scheme by the specifications of

the map

DEFINITION AND COMPARISON OF THE ENTITIES DEFINITION AND COMPARISON OF THE ENTITIES DEFINITION AND COMPARISON OF THE ENTITIES DEFINITION AND COMPARISON OF THE ENTITIES

EXISTINGEXISTINGTOPOLOGYTOPOLOGYEXISTINGEXISTING

TOPOLOGYTOPOLOGY

POLYLINESDB 1:10.000

BUFFER

DB25 NETWORK SCHEME CONSTRUCTIONDB25 NETWORK SCHEME CONSTRUCTIONDB25 NETWORK SCHEME CONSTRUCTIONDB25 NETWORK SCHEME CONSTRUCTION

CHECK OF THE OVERLAPPED AREAS

ROAD SYMBOLIC REPRESENTATIONROAD SYMBOLIC REPRESENTATIONROAD SYMBOLIC REPRESENTATIONROAD SYMBOLIC REPRESENTATION

HALF VALUE OF THE SYMBOLHALF VALUE OF THE SYMBOLHALF VALUE OF THE SYMBOLHALF VALUE OF THE SYMBOL

HALF VALUE OF THE TOLERANCEHALF VALUE OF THE TOLERANCEHALF VALUE OF THE TOLERANCEHALF VALUE OF THE TOLERANCE

THE OVERLAPPED AREAS ARE DELETED AND THE POLYLINES SHIFTED

NOTE:NOTE: THE RAILWAY, REPRESENTED BY POLYLINES, USES AS BUFFER ONLY THE RAILWAY, REPRESENTED BY POLYLINES, USES AS BUFFER ONLY

THE TOLERANCE VALUETHE TOLERANCE VALUE

NOTE:NOTE: THE RAILWAY, REPRESENTED BY POLYLINES, USES AS BUFFER ONLY THE RAILWAY, REPRESENTED BY POLYLINES, USES AS BUFFER ONLY

THE TOLERANCE VALUETHE TOLERANCE VALUE

To construct the symbology correctly and to test the polylines To construct the symbology correctly and to test the polylines we used a specific buffer valuewe used a specific buffer value

The change of the network scheme risks to lose the topological The change of the network scheme risks to lose the topological consistency of the data structureconsistency of the data structure

case (a)(a) deletes a non connected arc case (a)(a) deletes a non connected arc

case (b)(b) detects two new dangle nodes (regarding the bridge) which are automatically corrected by means of a tolerance value

case (b)(b) detects two new dangle nodes (regarding the bridge) which are automatically corrected by means of a tolerance value

case (c)(c) simplifies the intersectionscase (c)(c) simplifies the intersections

THREE POSSIBLE CASES OF ALTERATIONTHREE POSSIBLE CASES OF ALTERATIONTHREE POSSIBLE CASES OF ALTERATIONTHREE POSSIBLE CASES OF ALTERATION

TOPOLOGICAL TOPOLOGICAL RECONSTRUCTIONRECONSTRUCTION

(case b)(case b)

TOPOLOGICAL TOPOLOGICAL RECONSTRUCTIONRECONSTRUCTION

(case b)(case b)POLYLINE FEATURES

POLYLINE FEATURES

POINT FEATURES

USE OF THE GRAPH TO REALIZE A CORRECT SYMBOLIC REPRESENTATION

Completed the generalization we have constructed the layers related to the Completed the generalization we have constructed the layers related to the railway, bridges and roads railway, bridges and roads

Completed the generalization we have constructed the layers related to the Completed the generalization we have constructed the layers related to the railway, bridges and roads railway, bridges and roads

SOME REMARKSSOME REMARKSSOME REMARKSSOME REMARKS

NO BUFFER FLATNO BUFFER FLAT

NO MERGENO MERGE

NEW DEVELOPMENTS OF THE TOOL NEW DEVELOPMENTS OF THE TOOL ““TOPOLOGYTOPOLOGY ”

ADDING MORE COMMANDSADDING MORE COMMANDS

RECONSTRUCTION OF OTHER NETWORKS

HYDROGRAPHYTECHNOLOGICAL NETWORKS

AND SO ON

MAPINFO SOFTWARE DISADVANTEGES

NO CHECK on lines and symbols of millimeter sizeNO CHECK on lines and symbols of millimeter size

CONCLUSIONSCONCLUSIONSCONCLUSIONSCONCLUSIONS

The increase of automatic procedures needs to standardize entity The increase of automatic procedures needs to standardize entity definitions with their spatial and logical relationships definitions with their spatial and logical relationships

The increase of automatic procedures needs to standardize entity The increase of automatic procedures needs to standardize entity definitions with their spatial and logical relationships definitions with their spatial and logical relationships

Line and polygon generalization procedures must guarantee simplifications Line and polygon generalization procedures must guarantee simplifications topologically consistenttopologically consistent

Line and polygon generalization procedures must guarantee simplifications Line and polygon generalization procedures must guarantee simplifications topologically consistenttopologically consistent

It’s necessary, to fix for each entity in every different scale the type of It’s necessary, to fix for each entity in every different scale the type of representation (symbolical or real measure), the metric tolerance (graphic representation (symbolical or real measure), the metric tolerance (graphic error, minimum surface) and the possible characteristic of the object error, minimum surface) and the possible characteristic of the object (shape)(shape)

It’s necessary, to fix for each entity in every different scale the type of It’s necessary, to fix for each entity in every different scale the type of representation (symbolical or real measure), the metric tolerance (graphic representation (symbolical or real measure), the metric tolerance (graphic error, minimum surface) and the possible characteristic of the object error, minimum surface) and the possible characteristic of the object (shape)(shape)

A further topic of future research is the development of incremental A further topic of future research is the development of incremental update procedures to maintain large databases of topologically update procedures to maintain large databases of topologically

consistent multi-scaleconsistent multi-scale datadata

A further topic of future research is the development of incremental A further topic of future research is the development of incremental update procedures to maintain large databases of topologically update procedures to maintain large databases of topologically

consistent multi-scaleconsistent multi-scale datadata

Thank you

for your attention

Thank you

for your attention