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Contents
| Table of Contents |
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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:
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Each one of these usecases might rely on one or more of the below LRS data products:
Block
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| Status | ||||
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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
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Fig 3. Block Segment representation |
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| Status | ||||
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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 (Code 1)
- Alleys (Code 2)
- Ramps (Code 3)
- Service Roads (Code 4)
- Trails (Code 5)
- Driveways (Code 6)
- Walkways (Code 7)
Segmentation Rules:
- Streets, alleys, ramps, service roads and trails can break all others roadway type segments.
- At-grade type intersections are respected in this segmentation. See below for more information
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| Fig 2. SubBlock Segment representation |
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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
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| Fig |
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| 3. Approach representation |
Understanding Approach Intersection Direction
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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 4 for a graphic diagram.
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Fig 34. Approach intersection direction |
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FIELD | DESCRIPTION | DATA TYPE | EXAMPLE |
|---|---|---|---|
| RouteID | Unique identifier of the route that this approach is on | Text | 11035552 |
| ApproachID | Unique identifier of the Approach within the intersection (usually an integer value representation of the angle from the intersection). | Short Integer | 270 |
| SubBlockID | Unique identifier of the SubBlock that this approach is on | Text | 11035552-11035552_47054712-11035552_47053222 |
| IntersectionID | Unique identifier of the intersection that this approach is on | Text | 11035552_47054712 |
| FromMeasure | The begin measure of the approach (going in digitizing direction) along the route | Float | 823.788 |
| ToMeasure | The end measure of the approach (going in digitizing direction) along the route | Float | 833.788 |
| Angle | Represents the angle of the approach from the intersection | Text (needs to be changed?) | 270.073777185517 |
| Directionality | Represents the cardinal direction of the approach from the intersection | Text | West |
| RoadType | Represents the roadway type of this particular approach | Text | 1 |
| 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".
| Short Integer | 2 |
Blockface Segments
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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.
Blockface segments are one of the core elements of the ParkingZones, since
| Fig 2. Blockface Segment representation |
Blockface Attributes
FIELD | DESCRIPTION | DATA TYPE | EXAMPLE |
|---|---|---|---|
| ROUTEID | Unique identifier of the route that this blockface is on | Text | 11004002 |
| SIDE | Which side of the route is this blockface on, when looking in digitizing direction | Text | Left |
| MEAS_FROM | What measure along the route does this blockface begin | Float | 658.141 |
| MEAS_TO | What measure along the route does this blockface end | Float | 787.455 |
| BLOCKFACEKEY | Unique identifier for each blockface | Text | 4d547f51f668a28e0b9a652852bcdcf5 |
| Offset | Offset value to be able to visualize the blockfaces on a map | Short Integer | -3 |
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| Code | Description | Comments | ||||||
|---|---|---|---|---|---|---|---|---|
| 0 | At Grade
| 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. | ||||||
| 2 | Undefined | Not currently defined/categorized | ||||||
| 10 | Uncontrolled | Intersection without signal or signs to stop traffic flow | ||||||
| 11 | Two-way stop | One roadway is allowed to pass without stopping | ||||||
| 12 | All-way stop | All roadways are required to stop before proceeding | ||||||
| 13 | Signalized, Ped signal | Signalized intersection with pedestrian signals | ||||||
| 14 | Signalized, No Ped Signal | Signalized intersection without pedestrian signals | ||||||
| 15 | RR crossing, Signalized | Signalized railroad crossing | ||||||
| 16 | RR crossing, Signs Only | Non-signalized railroad crossing | ||||||
| 17 | Yield Sign | Intersection 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 |
| Measure | The LRS m-value (in Meters) along this route at the point of intersection. | Double | 213.113 |
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