History of the DDOT Centerline
SIS
SSD
StreetSegments
Representing the street centerlines, this feature class is one of the most important roadway assets to the DC DOT in terms of administration and maintenance. Although data preparation for this feature class was fairly straightforward, attention had to be paid to the creation of the: FromNodeID, ToNodeID, directionality and SSD_ID attributes as these were not in the test source data.
Through ArcObjects code, the FromNode and ToNode columns were populated with the NodeID values of base reference nodes that were coincident with the street segment endpoints.
Directionality Table
Description | DDOT_DIR (DCCL) | Directionality (SSD) |
One way (digitizing direction) | 1 | 0 |
One way (opposite digitizing direction) | -1 | 1 |
Two way | 2 | 2 |
Unknown | 0 | 3 |
Table 19: SSD Directionality
Segment ID Conventions
Centerline | SSD_ID | Length |
Street | QuadCode (1) + StCode (5) + FromNode (5) + ToNode (5) + 1RoadType (2) + Directionality (1) | 19 |
Ramp | FromStreetId (6) + ToStreetID (6) + Sequence(2) | 14 |
ServiceRoad | QuadCode (1) + StCode (5) + FromNode (5) + ToNode (5) + 1RoadType (2) + Directionality (1) | 19 |
Alley | QuadCode (1) +SquareNo (5) + Sequence (2) | 8 |
Driveways | Sequence |
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SnowPlowRoute | SSD_ID2 + Sequence (2) |
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Routing Reference Network | SSD_ID2+ RoadType (1) |
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1The RoadType is padded with ‘0’ to create two characters. 01 for street and 02 for service rd
2 SSD_ID of the source centerline
Intersections
This is a point geometry feature class representing street (centerline) segments intersections whose 14-character CLIntersectionID was created through ArcObjects code using the following convention:
- The first 6 characters represent the StreetID of the ‘OnStreet’ orPrimary Streetsegment. To be considered the Primary, segments in Quadrants 1 through 4 (whose StreetID values begin with 1 through 4) must: Leave an intersection (and consequently have a measure of 0) and possess the lowest StreetID value. However, should there exist a Quadrant 5 segment, (whose StreetID value begins with ‘5’), it automatically becomes the Primary direction notwithstanding. In addition, if a particular intersection has two Quadrant 5 segments, the segment with the lower StreetID value becomes the primary.
- The next 6 characters represent the StreetID of the intersecting street, which is the other leaving segment with the lowest StreetID
- The last 2 characters represent a sequence used to indicate instances where the first 12 characters of the CLIntersectionID are identical (i.e. two segments intersect more than once). Thus, if 2 segments with StreetIDs values 303133 and 303471 for primary and intersecting streets respectively, intersect 4 times, the CLIntersectionID values will be as follows: 30313330347100, 30313330347101, 30313330347102 and 30313330347103
The attributes of this feature class are described in the Table below:
Intersection ID Conventions
Attribute | Source / Description | Status | Example |
IntersectionPointID | A surrogate ID for the street intersection. Sequence generated by an Oracle database trigger | Populated |
|
SourceID | ID of the source linear feature class from the test data. Useful for tracing the lineage of the feature classes. |
|
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NodeID | NodeID of the intersection looking at the Base Reference layer | Populated |
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InServiceDate | Date when asset was commissioned into service – Data not available for prototype testing |
|
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OutOfServiceDate | Date when asset was taken out of service – Data not available for prototype testing |
|
|
UpdateTimestamp | Indicates the last time the table was updated. Generated by a database trigger that updates the field with the SysDate upon insert or update | Populated |
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LifeCycleStatus | Domain based (Status code). To be set to “active” for all features | Populated |
|
Description | Textual description of the centerline intersection |
|
|
SymbolRotation |
|
|
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CLIntersectionID | Unique identifier for the street intersections. Source is described above | Populated |
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NumberOfLink | Number of Street segmentsapproaching and leaving the intersection. | populated |
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ControlType <<SubtypeField>> | ControlType 1 = Controlled ControlType 2 = AllWayStop ControlType 3 = TwoWayStop ControlType 4 = UnControlled
|
Populated |
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Table 22: CenterlineIntersection Feature Class