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About

In order to make DDOT's LRS more useful to a variety of users, we create a variety of derivative data products to support a wide variety of usecases:

  • Addressing/geocoding (MAR Geocoding)
  • Asset management (Cityworks)
  • Project management (Protrack+)
  • Network Analysis (ArcGIS)
  • Safety Analysis (MIRE, Crash Data Analysis)
  • City Planning
  • Sidewalk/Pedestrian Analysis
  • ADA

Each one of these usecases might rely on one or more of the below LRS data products:

Block


PREVIOUSLY CALLED STREET SEGMENTS

For a city, street blocks are a very common way in which to organize and relate work (e.g. 'I need to fix a pothole on the 1600 Block of Pennsylvania Ave'). Although driveways or alleys may intersect streets, the Block segmentation requires that the segment remain unbroken.  A block will always begin at a street-to-street intersection and end at the next street-to-street intersection. 

Road Types included:

  • Streets

Segmentation Rules: 

  • Only Streets can break/segment other streets.
  • Only At-grade type intersections are respected in this segmentation.  See below for more information 


Fig 3. Block Segment representation

Block Attributes

FIELDDESCRIPTIONDATA TYPEEXAMPLE

StreetSegID

TEMPORARY FIELD

The old ID of this segmentLong Integer

10385

WE ARE CURRENTLY USING THIS FIELD FOR INTERNAL MIGRATION ONLY. ONCE PUBLISHED, USE 'BLOCKID' FOR UNIQUE IDENTIFIER

FromDateWhen this segment was createdDate1/1/2014
ToDateWhen this segment will expireDate<Null>
EventIDUnique randomly generated IDGuid
{962C2785-EE57-4B19-AEE9-D18CB5C30870}
RouteIDUnique ID of the route that this segment is onText11000202
FromMeasureThe measure along the route that this segment begins (meters)Double0
ToMeasureThe measure along the route that this segment ends (meters)Double148.683739
RouteNameName of the route on which this segment existsText2ND ST NW
SegmentTypeThe type of segmentShort Integer2 (Regular Single Centerline)
FromStreetName of streets that intersect the beginning of this segmentTextCONSTITUTION AVE NW
ToStreetName of streets that intersect the end of this segmentTextE ST NW/MITCH SNYDER PL NW
FromIntersectionID of intersection from which this segment beginsText11000202_11025352A
ToIntersectionID of intersection from which this segment endsText11000202_11031332_11061392

BlockID*

Key ID for the block; it is a concatenation of the RouteID, FromIntersectionID and ToIntersectionIDText11000202-11000202_11025352A-11000202_11031332_11061392
BlockKey*Primary key ID for the block. This is a GUID, which is derived from the BlockID valueGUID053c6863e95d1ca3401417cc1adc090d
FromIntersectionKey*Primary key ID for the From Intersection. This is a GUID, derived from FromIntersectionIDGUID8d9cf8ca94fc3048d095388d8d3621f6
ToIntersectionKey*Primary key ID for the To Intersection. This is a GUID, derived from ToIntersectionIDGUID4c68cea7e58591b579fd074bcdaff740
Directionality*Directionality of block (One way digitizing direction, one way against digitizing, two way)Short Integer1 [One way (Digitizing direction)]
created_userThe user that created the segmentSYS GENERATED<Null>
created_dateThe date the segment was createdSYS GENERATED<Null>
last_edited_userThe last user that made edits to this segmentSYS GENERATED<Null>
last_edited_dateThe date the segment was last editedSYS GENERATED<Null>
SHAPE_lengthLength of segmentSYS GENERATED<Null>

SubBlock


PREVIOUSLY CALLED ROADWAY SEGMENTS

SubBlock represents the full extent of our centerline network.  SubBlock is the finest-grained, 'base' segment from which all other segmentation patterns can be constructed (including Blocks).  SubBlock is the original source features for our DDOT Street Centerlines data

Road Types included:

  • Streets
  • Alleys
  • Ramps
  • Service Roads
  • Trails
  • Driveways

Segmentation Rules: 

  • Streets, alleys, ramps, service roads and trails can break all others of the same time.
  • At-grade type intersections are respected in this segmentation.  See below for more information 

Fig 2. SubBlock Segment representation

SubBlock Attributes

FIELDDESCRIPTIONDATA TYPEEXAMPLE
RouteIDUnique ID of the route that this segment is onText11037052
RouteNameName of the route that this segment is onTextFORT DR NW

SubBlockID*

Intelligent key ID for the sub-block; concatenation of the RouteID, FromIntersectionID and ToIntersectionIDText

11037052-11009492_11037052-11017482_11037052

SubBlockKey*Primary key ID for the subblock. This is a GUID, which is derived from the SubBlockID valueGUID16be813afac223d1e02d0deb9fba6c42
FromMeasureThe measure along the route that this segment beginsFloat135.291
ToMeasureThe measure along the route that this segment endsFloat329.825012
FromIntersectionIDThe ID of the intersection from which this segment beginsText11009492_11037052
ToIntersectionIDThe ID of the intersection at which this segment endsText11017482_11037052
FromIntersectionKey*Primary key ID for the From Intersection. This is a GUID, derived from FromIntersectionIDGUID82b9ad20d7eb65bb5dc336d7223bd061
ToIntersectionKey*Primary key ID for the To Intersection. This is a GUID, derived from ToIntersectionIDGUID55840779f58a725ae98a586b11156d06
FromSubBlock*Name of SubBlocks that intersect the beginning of this segmentTextALBEMARLE ST NW
ToSubBlock*Name of SubBlocks that intersect the end of this segmentTextBRANDYWINE ST NW
Directionality*Directionality of block (One way digitizing direction, one way against digitizing, two way)Short Integer1, One Way (Digitizing direction)
RoadTypeThe type of roadway it is (Street, Alley, Driveway, etc.)TextStreet
BlockIDThe BlockID of the block wherein this sub-block existsText11037052-11009492_11037052-11017482_11037052
BlockKey*Primary key ID for the block. This is a GUID, which is derived from the BlockID valueGUID16be813afac223d1e02d0deb9fba6c42

RoadwaySegID

TEMPORARY FIELD

The old ID of this segmentText

2917

WE ARE CURRENTLY USING THIS FIELD FOR INTERNAL MIGRATION ONLY. ONCE PUBLISHED, USE 'SUBBLOCKID' FOR UNIQUE IDENTIFIER

Intersection Approach Segments

Intersection Approach Segments are short segments of the route that approach an intersection, in other words, a short section of the road leading up to an intersection.

Structure of Approach Segments


Fig 2. Approach representation

Understanding Approach Intersection Direction

Intersection direction can be a confusing attribute to understand.  Its core purpose is to provide the network direction flow to the intersection point. (for each individual intersection approach)

When paired with cross-section data, this attribute gives the ability to determine if sections or lanes are approaching or departing the intersection.  This may be especially important in safety analyses (such as LTS) which focus primarily upon lane and sections which are approaching (not departing) an intersection.  See Fig 3 for a graphic diagram.  

Fig 3. Approach intersection direction

Intersection Approach Attributes

FIELD

DESCRIPTION

DATA TYPE

EXAMPLE

RouteIDUnique identifier of the route that this approach is onText11035552
ApproachIDUnique identifier of the Approach within the intersection (usually an integer value representation of the angle from the intersection).Short Integer270
SubBlockIDUnique identifier of the SubBlock that this approach is onText11035552-11035552_47054712-11035552_47053222
IntersectionIDUnique identifier of the intersection that this approach is onText11035552_47054712
FromMeasureThe begin measure of the approach (going in digitizing direction) along the routeFloat823.788
ToMeasureThe end measure of the approach (going in digitizing direction) along the routeFloat833.788
AngleRepresents the angle of the approach from the intersectionText (needs to be changed?)270.073777185517
DirectionalityRepresents the cardinal direction of the approach from the intersectionTextWest
RoadTypeRepresents the roadway type of this particular approachText1
IntersectionDirection

This is a field which helps users determine "intersection approach lanes" with DDOT's Cross-section LRS data.  Since the approaches are built in the digitizing direction, this field records inbound/outbound "approach direction". 

  • 1 = Approach direction toward the intersection point is in the same direction that of the route's measure direction.  Cross-section lanes with a Lane_Dir of 1 are the approaching lanes.
  • 2 = Approach direction toward the intersection point is in the opposite direction to the route's measure direction.  Cross-section lanes with a Lane_Dir of 2 are the approaching lanes.
Short Integer2

Blockface Segments


Blockface Segments are unbroken sections of the curb. A blockface can be made up of several subblocks, or just one subblock. Blockfaces are directional, so there will be segments on both sides of the road, each dependent on an unbroken length of curb.


Fig 2. Blockface Segment representation

Blockface Attributes

FIELD

DESCRIPTION

DATA TYPE

EXAMPLE

ROUTEIDUnique identifier of the route that this blockface is onText11004002
SIDEWhich side of the route is this blockface on, when looking in digitizing directionTextLeft
MEAS_FROMWhat measure along the route does this blockface beginFloat658.141
MEAS_TOWhat measure along the route does this blockface endFloat787.455
BLOCKFACEKEYUnique identifier for each blockfaceText4d547f51f668a28e0b9a652852bcdcf5
OffsetOffset value to be able to visualize the blockfaces on a mapShort Integer-3

SubBlock Intersections 


Intersections are automatically created, however they are not singular points.  The LRS creates a series of points - one for each intersecting road at that intersection.  For DDOT, it is more useful to have a single intersection point representing a given intersection.  Through a custom DDOT script, the collection of overlapping intersection points is reduced into a single representative point and this is our SubBlock Intersections Layer.  


Fig 1. Intersection representation

SubBlock Intersection Attributes

FIELD

DESCRIPTION

DATA TYPE

EXAMPLE

IntersectionID

Unique ID created by concatenating the ROUTEIDs that make up the intersection

Text

11077672_11094052

IntersectionName

Name of the intersection

Text

S ST NW & WISCONSIN AVE NW

IntersectionKey*Primary key ID for the intersection. This is a GUID, which is derived from the IntersectionID valueGUID0b56ed21fdb94cea77bf609468b67886
GradeThe type of intersection. For more information, check out the Intersection Grade Codes table below.Short Integer13, Signalized, Ped signal

Intersection Grade Codes

CodeDescriptionComments
0

At Grade TEMPORARY VALUE

Generic code for indicating that the roads at this point intersect each other.
1

Not at Grade

Not at Grade is an overpass/underpass situation where the roads don't connect.
2UndefinedNot currently defined/categorized
10UncontrolledIntersection without signal or signs to stop traffic flow
11Two-way stopOne roadway is allowed to pass without stopping
12All-way stopAll roadways are required to stop before proceeding
13Signalized, Ped signalSignalized intersection with pedestrian signals
14Signalized, No Ped SignalSignalized intersection without pedestrian signals
15RR crossing, SignalizedSignalized railroad crossing
16RR crossing, Signs OnlyNon-signalized railroad crossing
17Yield SignIntersection with a yield sign

IntersectionRoutes

IntersectionRoutes is a 1-to-many related table to SubBlock Intersections.  For each SubBlock Intersection, IntersectionRoutes contains 2 or more records - one for every intersecting route occurring at that location.

FIELD

DESCRIPTION

DATA TYPE

EXAMPLE

IntersectionID

Unique ID created by concatenating the ROUTEIDs that make up the intersection

Text

11048422_47053562

RouteID

The Unique ID for this particular route geometry

Text

11048422

MeasureThe LRS m-value (in Meters) along this route at the point of intersection.Double213.113
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