Digital map containing state-maintained and local-road centerlines for Spencer County, Kentucky.
Produced by the Kentucky Transportation Cabinet (KYTC), this data is to provide a base transportation network for use in Geographic Information Systems (GIS).
Highway centerline data was created with Global Positioning System (GPS) technology. See data-standard information in the "Cross Reference" tab.
publication date
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LIMITATION OF LIABILITY: MSD and the participants of the Louisville/Jefferson County Information Consortium (LOJIC) have no indication or reason to believe that there are any inaccuracies or defects of information incorporated in this work and make NO REPRESENTATIONS OF ANY KIND, INCLUDING, BUT NOT LIMITED TO, THE WARRANTIES OF MERCHANTBILITY OR FITNESS FOR A PARTICULAR USE, NOR ARE ANY SUCH WARRANTIES TO BE IMPLIED, WITH RESPECT TO THE INFORMATION OR DATA, FURNISHED HEREIN. The attached data is owned by the LOJIC participants and is protected by United States Copyright laws and applicable international copyright treaties and/or conventions.
| Boundary | Coordinate |
|---|---|
| Left | 1276852.500000 (survey feet) |
| Right | 1395068.125000 (survey feet) |
| Top | 237670.000000 (survey feet) |
| Bottom | 162220.026250 (survey feet) |
| Boundary | Coordinate |
|---|---|
| West | -85.514233 (longitude) |
| East | -85.100764 (longitude) |
| North | 38.149531 (latitude) |
| South | 37.938630 (latitude) |
Internal feature number.
ESRI
Feature geometry.
ESRI
Node, geometry and topology relationships are collected or generated to satisfy topological requirements. Some of these requirments include: arcs must begin and end at nodes, arcs must connect to each other at nodes, and arcs do not extend through nodes.
Data completeness for unrevised digital files reflects the content of the source graphic ie. DRGs, DOQQs, realignments, As-Builts, field maps and other agencies' documents. All future updates will be collected following the current Standards for KYTC Road Centerlines (see http://giac.ky.gov/giac_standards_trans.htm).
Attributes fall within three categories: structural attributes, descriptive attributes, and calculated attributes. Structural attributes uniquely identify individual arcs and are verified against fields in related Oracle tables. Descriptive attributes are compared against KYTC internal documents and field inspections. Calculated attribute fields are populated via script routines.
Accuracy of unrevised/pre-GPS files are based on the use of source graphics ie. 1:24000 DRGs. The target horizontal accuracy for the road layers was 1:24,000 (+/- 40 feet). Given the variety of sources for the data, it is recognized that the older centerlines do not always meet published national map accuracy standards. For data currently being collected and all GPS-based road centerline data, the KYTC Division of Planning uses the geospatial positional accuracy standards proposed by the Federal Geodetic Control Subcommittee (FGCS 1994). Road centerline collection methods are based on pseudorange measurements (FGCS Classification Band IX). These differential GPS (DGPS) methods, either in post processed or real-time modes, provide a resulting horizontal accuracy of less than 4 meter radius of the relative positional error circle with a 95% confidence. The target accuracy for new collection is sub-meter (< 1.0 meter), but it is recognized that some field conditions prevent attaining this. All county level coverages will have a published accuracy statement containing a relative positional error radius and a confidence level.
KYTC Divison of Planning, KY Area Development Districts
The centerline data goes through the following processes: data collection, data clean up, verification of accuracy, formatting into distributable GIS files, and publication/sharing. The foundation for non-GPS centerlines was captured through heads-up digitizing of scanned and registered USGS 7.5' topographic quadrangles. New roads and alignment changes to the existing road layers were added using As-Builts, field maps, and a variety of external agencies' documents. Each county's centerline collection must conform to criteria defined by KYTC's Division of Planning. While alternative methods for data collection can be used (photogrammetry, etc.), all data to be incorporated into KYTC coverages must meet or exceed the accuracy level defined by the Division of Planning and are subject to independent accuracy validation. The methods described below are provided as a successful blueprint for collecting centerline data at the KYTC defined accuracy level. KYTC DATA COLLECTION METHOD All public roads (defined above) are to be collected. The primary technology designated for use in road centerline collection is GPS. A GPS unit is mounted on vehicles (with the antenna on the driver's side) and roads are driven at normal traffic speeds. Antenna location on the vehicle & height (in feet & meters) is recorded in order to offset properly the centerline from the collection point. At least 95% of the mileage of all state maintained roads are located with differential GPS. At least 95% of the total mileage should be collected with DGPS. KYTC and its current contractors are using ASPEN software for the collection of road centerline GPS data. Epoch recording rate is to be 1 second for all roads except for Interstates. The epoch rate for Interstate should be 5 seconds. This provides efficient data capture while meeting the accuracy requirements. Alternative less accurate methods for collecting road position can be employed, such as DOQQs, but cannot exceed 5% of the total arc mileage but may exceed 5% of the total maintained road mileage. Two important data attributes that should be addressed in field data collection are directionality and arc breaks. KYTC's experience has found that more errors occur if these are left to the office cleanup phase. Directionality: All non-divided state roads were driven in two directions and then collapsed to generate a centerline. Divided Highways (where medians exist) were driven in both directions and then retained separately in the coverage. All local and one-way roads were driven in one direction and the appropriate offset applied. Arc Breaks: Arcs must break at pavement changes and the beginning and ending points of all ramps, Y-intersections, crossovers, and connectors. (Post-fieldwork processing will add breaks at city and county boundaries). DATA CLEAN-UP After field GPS collection centerline data is brought into a GIS and processed to remove obvious errors (both spatial and attribute). This involves cleaning up a variety of errors including spatial (multipath, over and undershoots, arc directionality reversals, etc.) and attribute errors (data entry miscoding, omission, transposition and "fat-finger". The data is also compared to known test points and lines for spatial verification of accuracy. HORIZONTAL ACCURACY VERIFICATION METHODS KYTC's spatial accuracy verification methodology is an adoption of the National Standard For Spatial Data Accuracy (NSSDA) testing methodology (FGDC-SBCD 1998:3-4). A minimum of 20 road intersection test points is taken within each county using DGPS. These locations are distributed proportionately throughout each county to reflect the geographic area of interest and distribute any error. Each test point is monumented with a P-K (a hardened masonry nail with a central dimple) or MAG nail (magnetized nail that is detectable even if buried). A DGPS unit is mounted onto a tripod over the point and a minimum of 180 positions is taken using a 1-second point-logging interval. KYTC then randomly tests a subset of these control points for each county to corroborate accuracy of the centerlines. Please note that these test points are for GPS centerline accuracy testing purposes only. They should not be used for land surveying purposes.
Dataset copied.
Dataset copied.
Metadata imported.
Downloadable Data
Although this data set has been processed successfully on a computer system at the State of Kentucky, Department of Transportation , Division of Planning, in our GPS/GIS Section as a Statewide GIS Mapping Project, no warranty expressed or implied is made by the State of Kentucky regarding the utility of the data on any system, nor shall the act of distribution constitute such a warranty. The State of Kentucky and Department of Transportation, Department of Highways, Division of Planning makes no expressed or implied warranties (including warranties of merchantability and fitness) with respect to the character, function, or capabilities of the electronic services or products or their appropriateness for any user purposes. In no event will the State of Kentucky and/or The Department of Transportation, Division of Planning be liable for any incidental, indirect, special, consequential or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products, any failure thereof or otherwise, and in no event will the State of Kentucky and/or The Department of Transportation, Division of Planning liability to the requestor or anyone else exceed the fee paid for the electronic service or product.
Must have software compatible with ESRI based file types.
Download from OGI http://ogi.ky.gov