229.00.18 Ark. Code R. 001
Introduction
The State Land Information Board, now the State GIS Board, developed this document in order to support the legislative initiatives to establish the Arkansas Spatial Data Infrastructure (Arkansas Code 15-21-5). Spatial data layers are often stored digitally and accessed through a relational database management system (RDBMS). Although the centerline file is a component of the Arkansas Spatial Data Infrastructure, the way in which people format and maintain it can differ. People often disagree on the way a particular spatial data layer structure should be organized. This can pose problems in terms of sharing, locating, and extracting spatial data information. It is intended that these standards will benefit the Geographic Information Systems (GIS) user communities in numerous ways, including but not limited to: The National Map Program1, The TIGER Modernization Program2, E-911 applications, routing services, and location dependent services.
The following standards specifically speak to methodologies for creating a seamless statewide Arkansas Centerline File with address ranges that are shareable, geocodable, and have a horizontal accuracy better than 10 meters.
Background
The State Land Information Board (SLIB) was created by Act 914 of the 1997 General
Assembly and is responsible for:
* Identifying problems and solutions in implementing a spatial data repository
* Developing and coordinating a schedule for state spatial data projects
* Recommending methods of financing for state spatial data projects
* Providing educational programs that are focused on spatial data technologies
* Coordinating collaborative projects
* Establishing spatial data standards (Section 4. (f) (1) of Arkansas Code 15-21-5).
Act 244 of 2009 renamed the Board to the State GIS Board.
Arkansas Code 15-21-5 An Act to Amend the Arkansas Code to Create the Geographic Information Office and Establish the Arkansas Spatial Data Infrastructure and for other purposes establishes these SLIB principles:
* Validity, consistency, comprehensiveness, availability, and currentness of data are essential components of all automated land information systems.
* Coordination with federal, state, regional, county, and municipal agencies, state universities and colleges, private firms, and others who require the same spatial data will reduce duplication of efforts and expense.
* Creation of new data in an accurate and usable format in accordance with the states shared technology architecture will ensure availability across state agencies.
Purpose
This standard is intended to make centerline files more uniform and horizontally accurate. This will facilitate the sharing of a statewide seamless centerline spatial data layer. Adhering to these standards will insure the "usability" of the spatial data theme and its attributes by multiple entities. This standard will insure a consistent manner in which the centerline and/or attributes are collected. This will enable the data to be merged seamlessly, and transferable regardless of creator or jurisdictional boundaries. All data used in the creation of the Arkansas Centerline File shall meet these standards.
*Note: Throughout the remainder of this document ACF shall refer to Arkansas Centerline File. This includes the vector spatial data layer and its attributes. The ACF shall be composed of centerline files created from multiple sources and/or entities. Centerline shall include all clearly defined passages through which a standard vehicle may travel as well as driveways extending more than 500 feet and/or driveways containing two or more addressed structures.
Technical Practices for Creating ACF Vector Layer geometry
ACF Feature Type:
Vector lines shall be used to represent centerlines. The ACF shall "seamlessly" match across jurisdiction boundaries (i.e., cities, counties, etc.). Address ranges shall be organized along the linear feature to support address geocoding. The address ranges shall be stored within the centerline attribute table of the geospatial dataset.
Topology:
The centerline file shall be processed using appropriate GIS procedures to create and maintain accurate topology, if intended for incorporation into the ACF program. In order to eliminate common dangle and intersect topological errors, care should be taken while digitizing to snap the endpoints of line centerline segments to endpoints of other line segments. At a minimum the following topology rules should be adhered to:
*Topology rules excerpted fromhttp://resources.esri.com.
Inclusion of Specific Geometric Elements:
In order to support the development and ongoing maintenance of the all public roads linear referencing system, otherwise known as the All Roads Network Of Linear Referenced Data (ARNOLD, http://www.fhwa.dot.gov/policyinformation/hpms/arnold.cfm), geometric elements representing particular road design types should be digitized in the ACF vector layer. Practices for digitizing these elements can be found in the subsequent Digitizing section.
Digitizing:
Centerline files intended for incorporation into the ACF program may be produced utilizing heads-up digitizing techniques. Heads-up digitizing methodologies used may include, but are not limited to, point mode, stream mode, spaghetti mode, or increment mode. Heads-up digitizing should be performed utilizing the following standards.
Capture scale should be 1:1,200
Projection - UTM Zone 15
Datum - North American Datum 1983 (NAD83)
Units - Meters
Source - At a minimum, the second Generation Digital Ortho Quarter Quadrangles
(DOQQs) that have verified horizontal accuracies should be used. However, the best available imagery should always be used given that many jurisdictions have acquired their own aerial imagery since the acquisition of the state DOQQs mentioned above.
Best practices should always be adhered to when digitizing features in the ACF vector layer. These shall include, but may not be limited to the following:
Edge Matching:
Where roads cross political boundaries, e.g. city, county, or state boundary, the linear centerline feature shall be snapped to the edge of the applicable boundary and properly segmented. The city, county, and state boundaries maintained by the Arkansas Department of Transportation (ArDOT) and the Arkansas GIS Office and available via gis.arkansas.gov should be used as the geometric features to which the road segments are snapped. Where a road centerline is coincident with a political boundary and different jurisdictions are on each side, e.g. a city and a county, a single centerline feature should be used and differences in naming and addressing practices attributable to the different jurisdictions should be accounted for by using the alternate fields.
Global Navigation Satellite System (GNSS):
Centerline files intended for incorporation into the ACF program may be produced utilizing current accepted standards for GNSS data collection.
Technical Practices for Creating ACF Attributes
The following standards apply to the collection and maintenance of the centerline attributes that are intended for incorporation into the ACF program.
Minimum Standards for ACF Attributes:
Table 1
Field Name | Length | Type | Alpha Case | Description |
PL_ADD_F | Long integer | Primary Left From Address number | ||
PL_ADD_T | Long integer | Primary Left To Address number | ||
PR_ADD_F | Long integer | Primary Right From Address number | ||
PR_ADD_T | Long integer | Primary Right To Address number | ||
PRE DIR | 2 | Text | Upper | Primary Directional Prefix |
PRE TYPE | 4 | Text | Proper | Primary Prefix Street Type |
PSTR NAM | 72 | Text | Proper | Primary Street Name |
PSTR_TYPE | 4 | Text | Proper | Primary Suffix Street Type |
PSUF_DIR | 2 | Text | Upper | Primary Directional Suffix |
PSTR_FULNAM | 255 | Text | Proper | Stores the complete primary street name |
CITY_L | 30 | Text | Proper | Stores the USPS preferred last line city name |
CITY_R | 30 | Text | Proper | Stores the USPS preferred last line city name |
COMM_L | 30 | Text | Proper | Stores the e 9-1-1 jurisdictional community |
COMM_R | 30 | Text | Proper | Stores the e 9-1-1 jurisdictional community |
CN R FIPS | 3 | Text | County FIPS code Right | |
CN L FIPS | 3 | Text | County FIPS code Left | |
STATE L | 2 | Text | Upper | State Left |
STATE R | 2 | Text | Upper | State Right |
ZIP5 L | 5 | Text | Zip Code Left | |
ZIP5_R | 5 | Text | Zip Code Left Right | |
UNIQUE_ID | Long integer | Unique Identifier | ||
META ID | 20 | Text | Metadata Identifier | |
ALTERNATE 1 | ||||
A1_LFADD | Long integer | Alternative 1 Left From Address number | ||
A1_LTADD | Long integer | Alternative 1 Left To Address number | ||
A1_RFADD | Long integer | Alternative 1 Right From Address number | ||
A1_RTADD | Long integer | Alternative 1 Right To Address number | ||
A1_PRTYP | 4 | Text | Proper | Alternative 1 Street Prefix Type |
A1_STR | 72 | Text | Proper | Alternative 1 Street Name |
A1_DRPR | 2 | Text | Upper | Alternative 1 Directional Prefix |
A1_STYP | 4 | Text | Proper | Alternative 1 Street Type |
A1_DRSF | 2 | Text | Upper | Alternative 1 Directional Suffix |
A1_FULNAM | 255 | Text | Proper | Alternative 1 complete street name |
ALTERNATE 2 | ||||
A2_LFADD | Long integer | Alternative 2 Left From Address number | ||
A2_LTADD | Long integer | Alternative 2 Left To Address number | ||
A2_RFADD | Long integer | Alternative 2 Right From Address number | ||
A2_RTADD | Long integer | Alternative 2 Right To Address number | ||
A2_PRTYP | 4 | Text | Proper | Alternative 2 Street Prefix Type |
A2_STR | 72 | Text | Proper | Alternative 2 Street Name |
A2_DRPR | 2 | Text | Upper | Alternative 2 Directional Prefix |
A2_STYP | 4 | Text | Proper | Alternative 2 Street Type |
A2_DRSF | 2 | Text | Upper | Alternative 2 Directional Suffix |
A2_FULNAM | 255 | Text | Proper | Alternative 2 complete street name |
ALTERNATE 3 | ||||
A3_LFADD | Long integer | Alternative 3 Left From Address number | ||
A3_LTADD | Long integer | Alternative 3 Left To Address number | ||
A3_RFADD | Long integer | Alternative 3 Right From Address number | ||
A3_RTADD | Long integer | Alternative 3 Right To Address number | ||
A3_PRTYP | 4 | Text | Proper | Alternative 3 Street Prefix Type |
A3_STR | 72 | Text | Proper | Alternative 3 Street Name |
A3_DRPR | 2 | Text | Upper | Alternative 3 Directional Prefix |
A3_STYP | 4 | Text | Proper | Alternative 3 Street Type |
A3_DRSF | 2 | Text | Upper | Alternative 3 Directional Suffix |
A3_FULNAM | 255 | Text | Proper | Alternative 2 complete street name |
RD_CLASS1 | 25 | Text | Upper | The entity by or through which a road is maintained. Acceptable values are "federal", "state", "county", "municipal", "private", "levee road", or "public". |
RD_DESIGN2 | 25 | Text | Upper | Design characteristic of the road. Acceptable values are "dual carriageway", "single carriageway", "traffic circle", "connector segment", "grade-separated ramp", "at-grade ramp", "frontage road", or "highway facility" |
RD_SURFTYP3 | 25 | Text | Upper | Road surface type. Recommended values are 'paved' or 'unpaved'. |
LOG_DIRECT4 | 25 | Text | Upper | Indication of whether travel on a dual carriageway road is in the log or antilog direction. Acceptable values are "log" or "antilog". |
AH_Dist | 2 | Text | The number of the Department District in which the road is contained (1 - 10). | |
AH_County | 25 | Text | The Department assigned number of the county in which the road is contained (1 - 75). | |
AH_Route | 100 | Text | The assigned official route number or name based on Department Road Inventory and official local road names. | |
AH_Section | 3 | Text | Department assigned section number of each highway and local road. | |
AH_BLM | 6 | Number | Department calculated begin log mile of each highway and local road segment. | |
AH_ELM | 6 | Number | Department calculated end log mile of each highway and local road segment. | |
AH_Length | 6 | Number | Department calculated length of each highway and local road segment. | |
AH_Seg_Num | 5 | Number | Calculated segment number based on road direction. | |
AH_Rev_ACF | Yes/No | Text | Proper | States if the road direction in the delivered file from AGISO was reversed to match the Department log direction (Yes or No). |
AH_ID | 150 | Text | Concatenated county x route x section x log direct x segment number. Unique ID required by FHWA | |
AH_RoadID | 150 | Text | Concatenated county x route x section x log direct for Dynamic Segmentation. | |
AH_Signed | 10 | Text | Proper | Manner in which each road is signed for quick retrieval. Interstate = Interstate Highways US = U.S. Highways State = State Highways Local = All other local roadways |
1'federal = maintained by specific federal agencies, e.g. U.S. Forest Service, U.S. Fish and Wildlife Service, U.S. Army Corps of Engineers, National Park Service, etc.
State = interstate highways, US highways, state highways, and any other road maintained by a state government entity
county = road officially accepted into a county road system and maintained as such by a county road department
municipal = road maintained by an incorporated municipality
private = any road or driveway not maintained by a public entity
levee road = road constructed atop a regulated levee under the jurisdiction of a local levee district
public = roads receiving some amount of county maintenance for public use, but not accepted as an official county road
2Each RD_DESIGN value is defined in the "Definition of Terms" section.
3A county may choose to maintain surface type attributes more detailed than "paved" or "unpaved". However, the RD_SURFTYP field will at a minimum carry the "paved" or "unpaved" attribute to meet the all public roads linear referencing system requirement.
4log = log direction, i.e. in the direction of increasing log mile values antilog = antilog direction, i.e. in the direction of decreasing log mile values
*Note: The line in this instance is a linear geospatial theme that represents a centerline. Address ranges are typically established for individual centerline segments so address matching may be performed. Whenever practical, street names and address ranges shall conform to the actual situs addresses assigned.
Typographic Conventions:
The "#" symbol, hyphens or other punctuations shall not be used in any part of centerline attribute files created with the intent to be incorporated into the ACF program.
Directional Prefixes & Suffixes:
Centerline files intended for incorporation into the ACF program shall use directional prefixes and suffixes established by the United States Postal Service. (Refer to Appendix A.) The directional prefixes and suffixes shall be uppercase.
Metadata Identifier:
Centerline files intended for incorporation into the ACF program shall have a metadata identifier that associates (links) the contributed file to its proper metadata. Each segment shall have a metadata code assigned at the state level.
Street Name:
When primary street names are numbers, the numeral shall be used rather than the actual spelling. For example, "1" would be used rather than "First". Names that are made up of numbers shall also include additional characters such as "th", "rd", "st" or "nd", e.g.
"1st", "2nd", "3rd", etc. These characters shall be included in the primary street name field.
Street names shall utilize capital and lower case letters. Common abbreviations are acceptable in the street name. These might include, but are not limited to Dr (Doctor) or Jr (Junior). This will insure the name fits the field length requirements.
In addition to the rules described above, naming conventions for the primary street names in the ACF should in all cases correspond to the actual situs addresses assigned by the local addressing authority. These should also be consistent with the naming conventions used in the situs address point data maintained by the local jurisdiction and with the local Master Street Address Guide (MSAG), if applicable.
Street Type:
Centerline files created with the intent to be incorporated into the ACF program shall use street abbreviations established by the United States Postal Service. The street type shall be composed of upper and lower case characters.
Unique Id:
Each line segment within the Arkansas Centerline File Program shall have a unique
identifier. The unique identifier shall be assigned at the state level.
Additional Considerations
Updates/ Maintenance:
A specific entity shall be identified to insure that the ACF is updated and maintained in a timely manner. Following spatial or attribute updates and/or modifications performed to the ACF shall be submitted to the entity responsible for performing quality control practices.
Quality Control:
Rigorous quality control techniques shall be implemented to insure the ACF has an acceptable horizontal accuracy and attribute integrity is maintained.
Horizontal Accuracy:
The National Standard for Spatial Data Accuracy (NSSDA)- part 3 shall be used to perform horizontal accuracy assessments on the ACF in several geographically dispersed areas. Centerline files created utilizing heads-up digitizing and GNSS techniques shall be tested, utilizing NSSDA- part 3 techniques in various locations.
Digital ortho-rectified photography may also be used to perform horizontal accuracy assessments in a more efficient and economical manner. This will enable the testing of larger portions of the spatial data theme.
Note: The horizontal accuracy of the digital ortho-rectified photography must be determined prior to utilizing it as a verification of the horizontal accuracy of the ACF.
Metadata:
Centerline files intended for incorporation into the ACF program shall have Federal Geographic Data Committee (FGDC) compliant metadata created for each spatial data file. Compliant metadata shall be provided with centerline files that are created, updated, or distributed by any parties participating in the ACF program. The metadata shall be supplied with the ACF anytime it is distributed and/or transferred among participants or other entities responsible for creating, performing quality control on, maintaining, updating, and/or distributing the ACF. The metadata shall be transferred in a FGDC standard format (i.e.- Z39.5, text or HTML file) and must have successfully passed through a FGDC compliant metadata parser.
ACF Program Participants:
Those participating in the ACF program shall follow the spatial, attribute, and metadata standards set forth in this document.
Centerline files created prior to the ACF program may be contributed to the program if FGDC compliant metadata is supplied. If the data is not in compliance with this standard, ACF program participants may standardize the centerline file and/or its attributes and incorporate the centerline file into the ACF program.
Distribution:
The ACF shall be distributed digitally via gis.arkansas.gov (Arkansas' Spatial Data Warehouse) at no cost to private or public users.
Definitions of Terms
Absolute Accuracy - A measure of the location of features on a map compared to their true position on the face of the earth.
Address Actual or Real - The simple, everyday element that designates a specific, situs location, such as a house number or an office suite.
Address matching - See Geocoding.
Address Range - set(s) of numbers usually comprised of four (4) distinct values that represent a theoretical situs address at either end of a centerline segment. Two numbers of the range represent the lowest addresses, while the other two represent the highest. The numbers are further distinguished as being on either the left or the right side of the segment. In topological terms, the low numbers are associated with the FROM node of the segment, while the high numbers are associated with the TO node. Likewise, left and right are determined by the direction of the segment, as defined by the FROM and TO nodes.
At-Grade Access Ramp - Connects roadways, permitting traffic flow from one uncontrolled access route to another without crossing another traffic stream.
Example:
Attribute(s) - Properties and characteristics of spatial data entities.
Arc/Node Mode - Arcs and nodes are defined by the user as they are digitized.
Character - (Also known as text or alpha)
Centerline - (See road)
Connector segments - Minor road segments that permit traffic flow from one route to another without crossing any other traffic. These segments can be signed for official use only for government, law enforcement or emergency use only.
Example:
Dual carriageway routes - A physically divided roadway that necessitates two or more sets of line work to adequately represent the roadway geometry. According to the Federal Highway Administration (FHWA), divided facilities should be represented as dual carriageway if:
Example:
Entity - Any object about which an organization chooses to collect data.
Frontage Road - Roadways that are often adjacent to interstate level highways and some single-carriageway highways.
Example:
Geocodable - An attribute database that is capable of being manipulated by GIS software to determine a theoretical address and its coordinates.
Geocoding - Mechanism for building a database relationship between addresses and geospatial features. When an address is matched to the geospatial features, geographic coordinates are assigned to the address.
Grade Separated Access Ramp - Connects roadways, permitting traffic flow from one mainline route to another without crossing any other traffic stream. These are typically found at controlled access interchanges, e.g. access ramps on an interstate highway. The grade separation implied by the name refers to the different levels at which the two mainline routes cross each other, i.e. at an overpass or underpass.
Example:
Highway Facility - Generally, these are public service facilities located along freeways and highways. Often similar in design, these may include weigh stations, welcome centers, overlooks, truck parking areas, and rest areas.
Example: Rest Area
Example: Weight Station
Example: Welcome Center
Increment Mode - Points are collected every n millimeters from the previous point.
NA - Not Applicable.
Point Mode - Single points are recorded one at a time.
Range - Numbers associated with segments of a digital centerline file that represent the actual high and low addresses at either end of each segment.
Relative Accuracy - A measure of the accuracy of individual features on a map when compared to other features on the same map.
Road (centerline) - Centerline shall include all clearly defined passages through which a standard vehicle may travel as well as driveways extending more than 500 feet and/or driveways containing two or more addressed structures.
Single carriageway routes - A roadway with one, two or more lanes arranged within a single course with no central reservation or median to separate opposing flows of traffic.
Example:
Situs - The proper or original position of a specific location. An element that designates a fixed site, such as the address of a property or building.
Stream Mode - Points are collected on regular intervals or time or distance.
Spaghetti Mode - Points are collected every n milliseconds.
Theoretical - A location that can be interpolated along a centerline file through geocoding software.
Topology - Spatial relationships and connectivity among graphic GIS features, such as points, lines, and polygons. These relationships allow display and analysis of "intelligent" data in GIS. Many topological structures incorporate begin and end relationships, direction and right / left identification.
Traffic circles - The intersection of two or more roadways in an uncontrolled at-grade interchange, intended to keep traffic moving through the intersection.
Example:
Vanity - A special address that is inconsistent with or an exception to the standard addressing schema.
Appendix A Directional Prefixes & Suffixes- United States Postal Service Abbreviations
E = East
N = North
NE = Northeast
NW = Northwest
S = South
SE = Southeast
SW = Southwest
W = West
References
1National Map Program- The U.S. Geological Survey (USGS) is committed to realigning and reinvigorating its topographic mapping activities to put truly current information into the hands of our customers, in a cost-effective way. Our vision is that, by working with partners, we will ensure that the Nation has access to and use of current, accurate, and nationally consistent base geographic information, including digital data and derived topographic maps. Our vision is documented in a report, The National Maphttp://nationalmap.usgs.gov/
2TIGER Modernization Program- The U.S. Census Bureau (Census Bureau) intends to issue a solicitation for full and open competition for services in support of the MAF/TIGER Modernization Program. The selected contractor will be expected to provide services for the MAF/TIGER Modernization strategic program objective number 1- Improve Address/Street Location Accuracy; Implement Automated Change Detection. The scope of the solicitation is addressed in the accompanying draft "Statement of Objectives" (SOO). The approach in fulfilling the Census Bureau's requirement will involve an acquisition process that is best explained in terms of the order events. http://www.census.gov/geo/mod/SOODraft2.pdf
Sources
B. Ozanich, 1996, E-911 Database Guide Second Edition, National Emergency Number Association
Federal Geographic Data Committee, 1999, NSDI Framework Transportation Identification Standards Draft 2
MapInfo, 1999, MapMarker Users Manual v. 5
R. Orli, L. Blake, F. Santos, A. Ippilito, 1996 Richard J. Oril, 1996, Address Data Quality and GeoCoding Standards, derived from U.S. Department of Housing and Urban Development
Spatial Data Standards, 1999, Spatial Data Standards- Facility Management Standards (software), U.S. Army Corps. Of Engineers, centerlines section
Street Address Working Group, November 24, 2000, Addressing Standard V 1.15 (in review), International Committee on Surveying & Mapping
SubCommittee on Cultural and Demographic Data, 2000, Address Data Content Standard, Federal Geodatic Data Committee
Acknowledgements- Arkansas I-Team Subcommittee
Christine Crawford: Chair | Arkansas One Call |
Bill Richardson | Arkansas Highway and Transportation Department |
Bob Scoggins | Arkansas Highway and Transportation Department |
Brian Culpepper | Center for Advanced Spatial Technologies |
Bryan Stewart: | Arkansas Highway and Transportation Department |
Chris Boudreaux | Conway Corporation |
Conya Spencer | Central Arkansas Planning and Development District |
Craig Best | United States Bureau of the Census |
Dale Enoch | Arkansas One Call |
Dorothy Rhodes | Arkansas Highway and Transportation Department |
Ed Crane | ESRI |
Farrell Adams | Arkansas Highway and Transportation Department |
Hilda Harris | Arkansas Highway and Transportation Department |
John Zimple | Arkansas Assessment Coordination Department |
Kathy Gunderman | Arkansas Highway and Transportation Department |
Kit Carson | Arkansas Highway and Transportation Department |
Larry Shanner | Pixxures |
Learon Dalby | Arkansas Geographic Information Office |
Margarett Sithong | Arkansas Highway and Transportation Department |
Mike Gardner | University of Arkansas at Fort Smith |
Paul Edwards | Arkansas Highway and Transportation Department |
Randy Everett | North Arkansas Electric Cooperative |
Randy Jones | First Electric |
Robert Fuhler | Arkansas Highway and Transportation Department |
Rusty Myers | Western Arkansas Planning and Development District |
Sharon Baker | Arkansas Highway and Transportation Department |
Shelby Johnson | Arkansas Geographic Information Office |
Sonny Sanders | ESRI |
Steve Teague | Arkansas Highway and Transportation Department |
Susan Cromwell | Arkansas State Land Information Board Member- Chair |
Suzanne Wiley | Arkansas State Land Information Board Member- Vice Chair |
Teresa Cline | Central Arkansas Planning and Development District |
Tim Mahan | Arkansas Highway and Transportation Department |
Tina Thompson | Western Arkansas Planning and Development District |
Todd Schroeder | First Electric |
Tom Pemberton | Pixxures |
Vince Gulliet | Carter and Burgess |
Walter Simpson | Geographic Data Technologies (GDT) |
Wes Flack | United States Bureau of the Census |
229.00.18 Ark. Code R. 001