Geometric networks and network datasets in a geodatabase in Informix

Geometric networks and network datasets in a geodatabase in Informix
Release 9.3

Geometric networks are collections of line (edge) and point (junction) feature classes in a feature dataset that possess a connectivity relationship. Geometric networks are used to model infrastructure, such as electirc utility lines and sewer systems.

Network datasets are also collections of feature classes that possess a connectivity relationship, but network datasets are created using three types of sources—edge feature sources, such as street centerlines, junction feature sources, such as point feature classes containing railroad crossings, and turn feature sources. They are used to model transportation. To use network datasets, you must have the Network Analyst extension installed.

The tables that get created with a network depend on whether you create a geometric network or a network dataset and also whether or not there are turns present in the network.

Networks in ArcCatalog

In the Catalog tree, feature datasets that contain geometric networks and network datasets in an Informix database management system (DBMS) look the same until you expand the dataset. Once the dataset is expanded, you will see either a geometric network or network dataset. For example, for a geometric network, you would see a layer similar to the following:

In this example, Water_Net is the geometric network in the dataset.

For a network dataset, you would see something similar to the following:

RoadNetwork_ND is the network dataset. RoadNetwork_ND_Junctions are the junctions for the RoadNetwork network dataset.

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Networks in an Informix DBMS

Networks are tracked in system tables and network tables. The following are the system tables used for a geometric network:

gdb_geomnetworks

gdb_networks

gdb_netweights

gdb_netweightasocs

gdb_netclasses

Network datasets are maintained in these system tables:

gdb_extensiondatasets

gdb_networks

gdb_netweights

gdb_edgeconnrules

gdb_jnconnrules

See System tables of a geodatabase in Informix for descriptions of these tables.

In addition to these tables the network is a set of variably sized tables. The size of these tables depends on the size of the network—for example, number of junctions #j and number of edges #e.

There are 10 fixed tables per network, and they are identified by the following naming convention n_*_<table_descriptor>, where the '*' represents the ID of the network in the gdb_networks table; for example, n_1_<table descriptor>, n_2_<table descriptor>. The actual number of tables varies depending on what type of network you create—geometric network or network dataset—and what elements the network contains. A maximum of 21 tables could get created for a network dataset with turns and weights.

All of these tables are versioned when the network itself is versioned.

The 10 tables that are always created are the n_<id>_desc, n_<id>_e<#>, n_<id>_estatus, n_<id>_etopo, n_<id>_flodir, n_<id>_jdesc, n_<id>_jstatus, n_<id>_jtopo, n_<id>_jtopo2, and n_<id>_props tables. (See below for descriptions.)

n_<id>_<>

Tables in the geodatabase that begin with n_ store information about networks.

n_<id>_desc

The n_<id>_desc table describes the elements of a network. This is a normalized table whose row count is equal to the number of junctions and the number of edges in a geometric network.

Field name	Field type	Description
oid	Int	The unique ID of an element in a geometric network
userclassid	Int	The ID of the feature class to which the element belongs
userid	Int	The object ID of the feature
usersubid	Int	The ID of an element in a feature; only applicable to complex edge features
elementtype	Smallint	A code indicating the type of network element 1 = junction 2 = edge
eid	Int	The unique element ID of the network element; the element ID is only unique for the type of network element

n_<id>_props

The n_<id>_props table contains a summary description of a a network's properties, such as element counts and maximum eid values.

Field name	Field type	Description
propertyid	Int	The unique ID of the network property
propertyname	Varchar(32)	The name of the property
propertyvalue	Int	The value of the property

NOTE: The n_<id>_desc and n_<id>_props tables can be viewed in the DBMS but should not be altered using SQL/third-party applications; doing so can corrupt the network.

All of the remaining network tables contain the same field names and types. The table names and what they track are described below the table definition. Those tables that track turns would not be used in a geometric network dataset.

Field name	Field type	Description
oid	Int	The unique ID of the BLOB page in the table NOT NULL
pagenumber	Int	The number of the BLOB page in the table NOT NULL
pageblob	Blob	The desciription for the element the table is describing, such as edge, edge status, etc.

Field name

Field type

Description

oid

Int

The unique ID of the BLOB page in the table

NOT NULL

pagenumber

Int

The number of the BLOB page in the table

NOT NULL

pageblob

Blob

The desciription for the element the table is describing, such as edge, edge status, etc.

n_<id>_e<#>—Describe network edge weights; # = 2, 3, 4, or 5

n_<id>_edesc—Describes the edges in a network

n_<id>_estatus—Describes the status of each edge including its deleted and disabled states

n_<id>_etopo—Describes the network edge topology or connectivity

n_<id>_eturn*—Indicates whether each edge participates in a turn

n_<id>_eturn2*—Lists which turns pass through each edge in the network

n_<id>_flodir—Describes the network flow direction

n_<id>_j<#>—Describe network junction weights; # = 0 or 1

n_<id>_jdesc—Describes the network junctions

n_<id>_jstatus—Describes the status of each network junction including its deleted and disabled states

n_<id>_jtopo—Describes the connectivity of junction elements with edge elements.

n_<id>_jtopo2—Describes the connectivity of junction elements with edge elements when there are multiple edges connected to a single junction.

n_<id>_jturn*—Indicates whether each junction participates in a turn

n_<id>_jturn2*—Lists which turns pass through each junction in the network

n_<id>_t<#>*—Describes the weight values of each turn element

n_<id>_tdefn*—Defines each turn element by listing the edges and junctions that make up the turn.

n_<id>_tdefn2*—Overflow table for the turn element definition; for example, if multiple edges make up a turn.

n_<id>_tdesc*—Describes the turns in a network

n_<id>_tstatus*—Describes the status of each network turn, including its deleted and disabled states.

*Would not be present in a geometric network or network dataset without turns.

Click the following link to view the tables involved in the Water_Net geometric network shown above:

Informix geometric network diagram

The link below will open a diagram of the tables that participate in the Roads_ND network dataset:

Informix network dataset diagram

In both diagrams, dashed lines indicate implicit relationships between tables, solid lines denote explicitly defined relationships. You will need Adobe Acrobat Reader to open the files.

The owner field in the gdb_objectclasses, gdb_networks, gdb_geomnetworks, gdb_featuredataset, and gdb_extensiondatasets tables all contain the same value, but to keep the diagram from being too cluttered, the implicit relationship between these fields is not shown. The same is true for the database name field in these tables; the values are the same but the relationship is not drawn on the diagram.

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Networks in an XML document

For a geometric network, the data element in an XML document is listed as type GeometricNetwork. The following is a portion of the XML document exported from the hydro2 dataset.

<DataElement xsi:type="esri:DEGeometricNetwork">
     <CatalogPath>/V=sde.DEFAULT/FD=sde92:gdb.Water/GN=sde92:gdb.Water_Net</CatalogPath> 
  <Name>sde92:gdb.Water_Net</Name> 
  <MetadataRetrieved>true</MetadataRetrieved> 
  <Metadata xsi:type="esri:XmlPropertySet">
  <XmlDoc><?xml version="1.0"?> <metadata xml:lang="en"><Esri><MetaID>{A4750260-72E0-4B84-9E59-A28ED020FBCF}</MetaID><CreaDate>20060530</CreaDate><CreaTime>14011400</CreaTime><SyncOnce>TRUE</SyncOnce></Esri></metadata></XmlDoc> 
     </Metadata>
  <DatasetType>esriDTGeometricNetwork</DatasetType> 
  <DSID>-1</DSID> 
  <Versioned>false</Versioned> 
  <CanVersion>true</CanVersion> 
  <Extent xsi:type="esri:EnvelopeN" /> 
  <SpatialReference xsi:type="esri:ProjectedCoordinateSystem">
     <WKT>PROJCS["World_Mercator",GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137.0,298.257223563]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Mercator"],PARAMETER["False_Easting",0.0],PARAMETER["False_Northing",0.0],PARAMETER["Central_Meridian",0.0],PARAMETER["Standard_Parallel_1",0.0],UNIT["Meter",1.0]]</WKT> 
  <XOrigin>-147.84354555</XOrigin> 
  <YOrigin>-0.843545550000002</YOrigin> 
  <XYScale>160000000</XYScale> 
  <ZOrigin>0</ZOrigin> 
  <ZScale>1</ZScale> 
  <MOrigin>0</MOrigin> 
  <MScale>1</MScale> 
  <XYTolerance>0.0002</XYTolerance> 
  <ZTolerance>4.7683715798108E-03</ZTolerance> 
  <MTolerance>2</MTolerance> 
  <HighPrecision>true</HighPrecision> 
     </SpatialReference>
  <NetworkType>esriNTUtilityNetwork</NetworkType> 
  <OrphanJunctionFeatureClassName /> 
  <FeatureClassNames xsi:type="esri:Names" /> 
  <ConnectivityRules xsi:type="esri:ArrayOfConnectivityRule" /> 
  <NetworkWeights xsi:type="esri:ArrayOfNetWeight" /> 
  <WeightAssociations xsi:type="esri:ArrayOfNetWeightAssociation" /> 
     </DataElement>

The following is an excerpt from an XML document created by exporting from a network dataset. The edge and junction elements' properties are listed below:

<EdgeFeatureSources xsi:type="esri:ArrayOfEdgeFeatureSource">
   <EdgeFeatureSource xsi:type="esri:EdgeFeatureSource">
   <ID>1</ID> 
   <ClassID>99</ClassID> 
   <Name>sde92:gdb.Streets</Name> 
   <ElementType>esriNETEdge</ElementType> 
   <Properties xsi:nil="true" /> 
   <FromElevationFieldName /> 
   <ToElevationFieldName /> 
   <Connectivity xsi:type="esri:PropertySet">
   <PropertyArray xsi:type="esri:ArrayOfPropertySetProperty">
   <PropertySetProperty xsi:type="esri:PropertySetProperty">
   <Key>Version</Key> 
   <Value xsi:type="xs:short">1</Value> 
     </PropertySetProperty>
   <PropertySetProperty xsi:type="esri:PropertySetProperty">
   <Key>UsesSubtypes</Key> 
     <Value xsi:type="xs:short">0</Value> 
   </PropertySetProperty>
   <PropertySetProperty xsi:type="esri:PropertySetProperty">
   <Key>ClassConnectivity</Key> 
   <Value xsi:type="xs:short">1</Value> 
     </PropertySetProperty>
   <PropertySetProperty xsi:type="esri:PropertySetProperty">
   <Key>SubtypeConnCount</Key> 
   <Value xsi:type="xs:int">0</Value> 
     </PropertySetProperty>
   <PropertySetProperty xsi:type="esri:PropertySetProperty">
   <Key>DefaultGroup</Key> 
   <Value xsi:type="xs:int">1</Value> 
     </PropertySetProperty>
   <PropertySetProperty xsi:type="esri:PropertySetProperty">
   <Key>GroupCount</Key> 
   <Value xsi:type="xs:int">0</Value> 
     </PropertySetProperty>
     </PropertyArray>
     </Connectivity>
     </EdgeFeatureSource>
     </EdgeFeatureSources>
   <JunctionFeatureSources xsi:type="esri:ArrayOfJunctionFeatureSource" /> 
   <SystemJunctionSources xsi:type="esri:ArrayOfSystemJunctionSource">
   <SystemJunctionSource xsi:type="esri:SystemJunctionSource">
   <ID>2</ID> 
   <ClassID>1683</ClassID> 
   <Name>sde92:gdb.RoadNetwork_ND_Junctions</Name> 
   <ElementType>esriNETJunction</ElementType> 
   <Properties xsi:nil="true" /> 
   <ElevationFieldName /> 
     </SystemJunctionSource>
     </SystemJunctionSources>
   <TurnFeatureSources xsi:type="esri:ArrayOfTurnFeatureSource" /> 
   <EvaluatedNetworkAttributes xsi:type="esri:ArrayOfEvaluatedNetworkAttribute">
   <EvaluatedNetworkAttribute xsi:type="esri:EvaluatedNetworkAttribute">
   <ID>1</ID> 
   <Name>speed</Name> 
   <Units>Unknown</Units> 
   <DataType>esriNADTBoolean</DataType> 
   <UsageType>esriNAUTRestriction</UsageType> 
   <UserData xsi:nil="true" /> 
   <UseByDefault>true</UseByDefault> 
   <AttributeParameters xsi:type="esri:ArrayOfNetworkAttributeParameter" /> 
     </EvaluatedNetworkAttribute>
   <EvaluatedNetworkAttribute xsi:type="esri:EvaluatedNetworkAttribute">
   <ID>2</ID> 
   <Name>oneway</Name> 
   <Units>Unknown</Units> 
   <DataType>esriNADTBoolean</DataType> 
   <UsageType>esriNAUTRestriction</UsageType> 
   <UserData xsi:nil="true" /> 
   <UseByDefault>true</UseByDefault> 
   <AttributeParameters xsi:type="esri:ArrayOfNetworkAttributeParameter" /> 
     </EvaluatedNetworkAttribute>
   <EvaluatedNetworkAttribute xsi:type="esri:EvaluatedNetworkAttribute">
   <ID>3</ID> 
   <Name>timeofday</Name> 
   <Units>Unknown</Units> 
   <DataType>esriNADTInteger</DataType> 
   <UsageType>esriNAUTCost</UsageType> 
   <UserData xsi:nil="true" /> 
   <UseByDefault>true</UseByDefault> 
   <AttributeParameters xsi:type="esri:ArrayOfNetworkAttributeParameter" /> 
     </EvaluatedNetworkAttribute>
   </EvaluatedNetworkAttributes>
   <NetworkAssignments xsi:type="esri:ArrayOfNetworkAssignment">
   <NetworkAssignment xsi:type="esri:NetworkAssignment">
   <IsDefault>true</IsDefault> 
   <ID>-1</ID> 
   <NetworkAttributeName>speed</NetworkAttributeName> 
   <NetworkElementType>esriNETJunction</NetworkElementType> 
   <NetworkEvaluatorCLSID>{318C4B91-F5D2-467A-996C-0AB51B0D8FF2}</NetworkEvaluatorCLSID> 
   <NetworkEdgeDirection>esriNEDNone</NetworkEdgeDirection> 
   <NetworkEvaluatorData xsi:type="esri:PropertySet">
   <PropertyArray xsi:type="esri:ArrayOfPropertySetProperty">
     <PropertySetProperty xsi:type="esri:PropertySetProperty">
   <Key>Version</Key> 
   <Value xsi:type="xs:short">1</Value> 
   </PropertySetProperty>
   <PropertySetProperty xsi:type="esri:PropertySetProperty">
   <Key>ConstantValue</Key> 
   <Value xsi:type="xs:boolean">false</Value> 
     </PropertySetProperty>
     </PropertyArray>
     </NetworkEvaluatorData>
     </NetworkAssignment>
   <NetworkAssignment xsi:type="esri:NetworkAssignment">
   <IsDefault>true</IsDefault> 
   <ID>-1</ID> 
   <NetworkAttributeName>speed</NetworkAttributeName> 
   <NetworkElementType>esriNETEdge</NetworkElementType> 
   <NetworkEvaluatorCLSID>{318C4B91-F5D2-467A-996C-0AB51B0D8FF2}</NetworkEvaluatorCLSID> 
   <NetworkEdgeDirection>esriNEDNone</NetworkEdgeDirection> 
   <NetworkEvaluatorData xsi:type="esri:PropertySet">
   <PropertyArray xsi:type="esri:ArrayOfPropertySetProperty">
   <PropertySetProperty xsi:type="esri:PropertySetProperty">
   <Key>Version</Key> 
   <Value xsi:type="xs:short">1</Value> 
     </PropertySetProperty>
   <PropertySetProperty xsi:type="esri:PropertySetProperty">
   <Key>ConstantValue</Key> 
   <Value xsi:type="xs:boolean">false</Value> 
     </PropertySetProperty>
     </PropertyArray>
     </NetworkEvaluatorData>
     </NetworkAssignment>
   <NetworkAssignment xsi:type="esri:NetworkAssignment">
   <IsDefault>true</IsDefault> 
   <ID>-1</ID> 
   <NetworkAttributeName>speed</NetworkAttributeName> 
   <NetworkElementType>esriNETTurn</NetworkElementType> 
   <NetworkEvaluatorCLSID>{318C4B91-F5D2-467A-996C-0AB51B0D8FF2}</NetworkEvaluatorCLSID> 
   <NetworkEdgeDirection>esriNEDNone</NetworkEdgeDirection> 
   <NetworkEvaluatorData xsi:type="esri:PropertySet">
   <PropertyArray xsi:type="esri:ArrayOfPropertySetProperty">
   <PropertySetProperty xsi:type="esri:PropertySetProperty">
   <Key>Version</Key> 
   <Value xsi:type="xs:short">1</Value> 
     </PropertySetProperty>
   <PropertySetProperty xsi:type="esri:PropertySetProperty">
   <Key>ConstantValue</Key> 
   <Value xsi:type="xs:boolean">false</Value> 
     </PropertySetProperty>
     </PropertyArray>
     </NetworkEvaluatorData>
     </NetworkAssignment>
   <NetworkAssignment xsi:type="esri:NetworkAssignment">
   <IsDefault>true</IsDefault> 
   <ID>-1</ID> 
   <NetworkAttributeName>oneway</NetworkAttributeName> 
   <NetworkElementType>esriNETJunction</NetworkElementType> 
   <NetworkEvaluatorCLSID>{318C4B91-F5D2-467A-996C-0AB51B0D8FF2}</NetworkEvaluatorCLSID> 
   <NetworkEdgeDirection>esriNEDNone</NetworkEdgeDirection> 
   <NetworkEvaluatorData xsi:type="esri:PropertySet">
   <PropertyArray xsi:type="esri:ArrayOfPropertySetProperty">
   <PropertySetProperty xsi:type="esri:PropertySetProperty">
   <Key>Version</Key> 
   <Value xsi:type="xs:short">1</Value> 
     </PropertySetProperty>
   <PropertySetProperty xsi:type="esri:PropertySetProperty">
   <Key>ConstantValue</Key> 
   <Value xsi:type="xs:boolean">false</Value> 
     </PropertySetProperty>
     </PropertyArray>
     </NetworkEvaluatorData>
     </NetworkAssignment>
   <NetworkAssignment xsi:type="esri:NetworkAssignment">
   <IsDefault>true</IsDefault> 
   <ID>-1</ID> 
   <NetworkAttributeName>oneway</NetworkAttributeName> 
   <NetworkElementType>esriNETEdge</NetworkElementType> 
   <NetworkEvaluatorCLSID>{318C4B91-F5D2-467A-996C-0AB51B0D8FF2}</NetworkEvaluatorCLSID> 
   <NetworkEdgeDirection>esriNEDNone</NetworkEdgeDirection> 
   <NetworkEvaluatorData xsi:type="esri:PropertySet">
   <PropertyArray xsi:type="esri:ArrayOfPropertySetProperty">
   <PropertySetProperty xsi:type="esri:PropertySetProperty">
   <Key>Version</Key> 
   <Value xsi:type="xs:short">1</Value> 
     </PropertySetProperty>
   <PropertySetProperty xsi:type="esri:PropertySetProperty">
   <Key>ConstantValue</Key> 
   <Value xsi:type="xs:boolean">false</Value> 
     </PropertySetProperty>
     </PropertyArray>
     </NetworkEvaluatorData>
     </NetworkAssignment>
   <NetworkAssignment xsi:type="esri:NetworkAssignment">
   <IsDefault>true</IsDefault> 
   <ID>-1</ID> 
   <NetworkAttributeName>oneway</NetworkAttributeName> 
   <NetworkElementType>esriNETTurn</NetworkElementType> 
   <NetworkEvaluatorCLSID>{318C4B91-F5D2-467A-996C-0AB51B0D8FF2}</NetworkEvaluatorCLSID> 
   <NetworkEdgeDirection>esriNEDNone</NetworkEdgeDirection> 
   <NetworkEvaluatorData xsi:type="esri:PropertySet">
   <PropertyArray xsi:type="esri:ArrayOfPropertySetProperty">
   <PropertySetProperty xsi:type="esri:PropertySetProperty">
   <Key>Version</Key> 
   <Value xsi:type="xs:short">1</Value> 
     </PropertySetProperty>
   <PropertySetProperty xsi:type="esri:PropertySetProperty">
   <Key>ConstantValue</Key> 
   <Value xsi:type="xs:boolean">false</Value> 
     </PropertySetProperty>
     </PropertyArray>
     </NetworkEvaluatorData>
     </NetworkAssignment>
   <NetworkAssignment xsi:type="esri:NetworkAssignment">
   <IsDefault>true</IsDefault> 
   <ID>-1</ID> 
   <NetworkAttributeName>timeofday</NetworkAttributeName> 
   <NetworkElementType>esriNETJunction</NetworkElementType> 
   <NetworkEvaluatorCLSID>{318C4B91-F5D2-467A-996C-0AB51B0D8FF2}</NetworkEvaluatorCLSID> 
   <NetworkEdgeDirection>esriNEDNone</NetworkEdgeDirection> 
   <NetworkEvaluatorData xsi:type="esri:PropertySet">
   <PropertyArray xsi:type="esri:ArrayOfPropertySetProperty">
   <PropertySetProperty xsi:type="esri:PropertySetProperty">
   <Key>Version</Key> 
   <Value xsi:type="xs:short">1</Value> 
     </PropertySetProperty>
   <PropertySetProperty xsi:type="esri:PropertySetProperty">
   <Key>ConstantValue</Key> 
   <Value xsi:type="xs:int">0</Value> 
     </PropertySetProperty>
     </PropertyArray>
     </NetworkEvaluatorData>
     </NetworkAssignment>
   <NetworkAssignment xsi:type="esri:NetworkAssignment">
   <IsDefault>true</IsDefault> 
   <ID>-1</ID> 
   <NetworkAttributeName>timeofday</NetworkAttributeName> 
   <NetworkElementType>esriNETEdge</NetworkElementType> 
   <NetworkEvaluatorCLSID>{318C4B91-F5D2-467A-996C-0AB51B0D8FF2}</NetworkEvaluatorCLSID> 
   <NetworkEdgeDirection>esriNEDNone</NetworkEdgeDirection> 
   <NetworkEvaluatorData xsi:type="esri:PropertySet">
   <PropertyArray xsi:type="esri:ArrayOfPropertySetProperty">
   <PropertySetProperty xsi:type="esri:PropertySetProperty">
   <Key>Version</Key> 
   <Value xsi:type="xs:short">1</Value> 
     </PropertySetProperty>
   <PropertySetProperty xsi:type="esri:PropertySetProperty">
   <Key>ConstantValue</Key> 
   <Value xsi:type="xs:int">0</Value> 
     </PropertySetProperty>
     </PropertyArray>
     </NetworkEvaluatorData>
     </NetworkAssignment>
   <NetworkAssignment xsi:type="esri:NetworkAssignment">
   <IsDefault>true</IsDefault> 
   <ID>-1</ID> 
   <NetworkAttributeName>timeofday</NetworkAttributeName> 
   <NetworkElementType>esriNETTurn</NetworkElementType> 
   <NetworkEvaluatorCLSID>{318C4B91-F5D2-467A-996C-0AB51B0D8FF2}</NetworkEvaluatorCLSID> 
   <NetworkEdgeDirection>esriNEDNone</NetworkEdgeDirection> 
   <NetworkEvaluatorData xsi:type="esri:PropertySet">
   <PropertyArray xsi:type="esri:ArrayOfPropertySetProperty">
   <PropertySetProperty xsi:type="esri:PropertySetProperty">
   <Key>Version</Key> 
   <Value xsi:type="xs:short">1</Value> 
     </PropertySetProperty>
   <PropertySetProperty xsi:type="esri:PropertySetProperty">
   <Key>ConstantValue</Key> 
   <Value xsi:type="xs:int">0</Value> 
     </PropertySetProperty>
     </PropertyArray>
     </NetworkEvaluatorData>
     </NetworkAssignment>
   </NetworkAssignments>
 <ConfigurationKeyword>NETWORK_DEFAULTS</ConfigurationKeyword> 
  </DataElement>

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Geometric networks and network datasets in a geodatabase in Informix

Geometric networks and network datasets in a geodatabase in Informix

Networks in ArcCatalog

Networks in an Informix DBMS

Networks in an XML document

See Also