Transcript Advanced Editing in ArcEditor

Advanced Editing:
Rules-Based Topology in
ArcEditor
What is Topology?
• Historically, topology is the set of geometric
relationships, determined mathematically,
between connecting or adjacent features in a
geographic dataset.
• e.g. FNODE#, TNODE#, LPOLY#, RPOLY#
fields in a line (streets) ArcInfo coverage.
What is Topology?
• With advances in GIS software, topology
has been taking on more of a rule-based
approach.
• In a geodatabase, a topology is a set of
governing rules applied to feature classes
that explicitly defines the spatial
relationships that must exist between
feature data.
ArcView vs. ArcEditor
• Editing shared features is the same.
ArcEditor – Topology or Map Topology
ArcView – Map Topology
• ArcEditor – Rule-based (Topology)
• ArcView – Non rule-based (Map Topology)
Topology and Feature Geometry
Geometries involved in a topology:
• Edges - Line segments that define lines or polygons
• Nodes - Points at the end of an edge
Topology and Feature Geometry
Ways of sharing a geometry:
Line features can share edges and nodes
Vertices define the shape of edges
Polygon features also share edges and nodes
Why Use Topology
• Ensure data quality
• Easily edit shared boundaries and
features
• More accurately model the real world
Characteristics of a Topology
• Requires an ArcEditor or ArcInfo license.
• Can only be created for feature classes in a
geodatabase. (not shapefiles)
• Feature classes participating in a topology must
have the same spatial reference.
• A topology can only describe relationships
between features within the same feature dataset
of the same geodatabase.
• A feature class cannot participate in more than
one topology.
Properties of a Topology
• Topologies store three sets of parameters:
1) Rules – Define the permissible
spatial relationships between features.
2) Cluster Tolerance – The distance
at which vertices are considered
coincident.
3) Ranks – Control which features
may be moved to other features
during validation.
Properties of a Topology
• Topologies also maintain a feature layer that store:
Dirty Areas - Areas that have been
edited since validation. Requires
another validation to discover any
errors.
Errors - Violations of a topology rule detected during validation.
Exceptions - Legitimate exceptions to a topology rule.
Topology Workflow
Organize Data
Setup the Topology
Validate Entire Topology
Done
No Errors
Check for Errors
Errors Exist
Fix Errors/Mark as Exceptions
Validate Topology of Dirty Areas
Edit Data
Building a Topology
Organize your data
Start the Topology Wizard
Building a Topology
Name the new
topology.
Set the cluster tolerance.
(in most cases, use the
default value)
Building a Topology
Determine which features you want
to participate in the topology.
Building a Topology
Set the number of
allowed ranks.
Set the rank of
each feature class.
Begin adding rules
to your topology.
Building a New Topology
Rules used by DDP:
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Study Areas Must Not Overlap
Study Areas Must Not Have Gaps
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•
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Streets Must Not Self-Intersect
Streets Must Not Self-Overlap
Streets Must Not Have Dangles
Streets Must Not Intersect or Touch
Interior
•
Schools Must be Properly Inside Study
Areas.
Building a Topology
Review the Summary Report &
validate the topology.
The topology now
appears in the
geodatabase.
Reviewing a Topology’s Properties
• Accessed through ArcCatalog or
ArcMap
Time for Exercise 1
• Follow the instructions in the handout.
• Stop at the end of Exercise 1.
Review the Topology Workflow
Organize Data
Setup the Topology
Validate Entire Topology
Done
No Errors
Check for Errors
Errors Exist
Fix Errors/Mark as Exceptions
Validate Topology of Dirty Areas
Edit Data
The Topology Toolbar
Topology Drop Down Menu
Show Shared Features
Map Topology Button
Validate Topology in Specified Area
(AV Disabled)
Construct Features Button
Validate Topology in Current Extent
(AV Disabled)
Planarize Lines Button
Validate Entire Topology
(AV Disabled)
(AV Disabled)
Topology Edit Tool
Fix Topology Error Tool
(AV Disabled)
Error Inspector Button
(AV Disabled)
Validating a Topology
• You have several options:
1) Using ArcCatalog
2) Using ArcMap (during an Edit Session).
c) Validate Entire Topology
b) Validate in Current Extent
a) Validate in Specified Area
Identifying Topology Errors
• Use either the Error Inspector or the Fix Topology Tool to
find and identify topology errors.
Error Inspector:
Identifying Topology Errors
Fix Topology Tool:
like a selection tool with more functionality
Fixing Topology Errors
• All topology fixes are done during an edit session in ArcMap.
• Select an error with the Error Inspector or Fix Topology Tool and
apply one of the pre-described fixes.
• Different rules have different fixes
available. Lets take a look…
Fixing Topology Errors in Study Areas
Fixing Overlaps:
Fixing Topology Errors in Study Areas
Fixing Gaps:
Fixing Topology Errors in Streets
• Intersect or Touch Interior, Dangles, Self-Intersections,
Self-Overlaps
Dangles:
Intersect or Touch Interior:
(Or select the features and
click Planarize Lines
)
Fixing Topology Errors in Streets
Self-Overlaps & Self-Intersections:
Fixing Topology Errors in Schools
• Schools must be properly inside Study Areas:
Marking Errors as Exceptions
In some cases you will have errors that break a
topology rule, but are legitimate exceptions to
that rule.
Time for Exercise 2
• Follow the instructions in the handout
• Stop at the end of Exercise 2
Advanced Editing in ArcEditor
Questions?
Other Topology Editing
• Moving shared features
• Using features in one feature class to construct
features in other feature classes
Moving Shared Features
Constructing Features from Features
in Different Feature Classes
Advanced Editing in ArcEditor
Questions?