The roads data set was generated for the Front Range Infrastructure Resources (FRIR) Project as a base cartographic layer. The data set contains the project's 45 1:24,000-scale quadrangle demonstration area that covers the Front Range of Colorado, south from Ft. Collins to the southern portion of Denver metropolitan area (not including Highlands Ranch, Douglas County); and west from Denver International Airport to the eastern foothills of the Rocky Mountains. For more information on this project, visit the Colorado Front Range Infrastructure Resources Project web site: http://rockyweb.cr.usgs.gov/frontrange/datasets.htm Procedures involved in compiling the road data include (1) obtaining 1 meter digital imagery and ancillary data for collecting, interpreting, and classifying the road features, (2) compiling the Digital Line Graph (DLG) vector data by 1:24,000-scale USGS quadrangle tiles, (3) merging the 1:24,000-scale quadrangle tiles into one seamless data set, and (4) translating and reattributing the features into user-friendly data sets. The translated attribution is described below in the Supplemental_Information section.
The demand for GIS data has increased recently, especially in rapidly growing metropolitan areas. Many state, regional, and local planning agencies require up-to-date road networks and other cartographic base information for various applications including modeling urban growth, determining land suitability for future development, monitoring land use changes and impacts on the environment, understanding land use patterns, and developing policies that could encourage or discourage certain land use zoning. Base cartographic layers are part of the USGS FRIR project cooperative effort to provide qualitative and quantitative information about infrastructure (aggregate, energy, water, habitat) features needed by growing urban regions like the Denver metropolitan area. The objective of the project is to develop GIS information about water and other themes in such a way that decision makers can use this information to make land use planning decisions, growth models and will be used by the project scientists for multiple studies of the changing landscape of the Front Range and the impact on various resources. In addition to roads, the USGS has created six other base cartographic layers consisting of: hydrography (FRIHY), miscellaneous transportation (FRIMT), railroads (FRIRR), manmade structures (FRIMS), public land survey system (FRIPL), and boundaries (FRIBD). FRIRD contains line attributed features. The data layers are available at http://rockyweb.cr.usgs.gov/frontrange/datasets.htm
CODES: ROAD OVERLAY: This document lists the codes specific to the road coverage as they pertain to item fields. The original classification system is taken from DLG major/minor attribute codes. The CAT item specifies the overlay type and takes the place of DLG major codes. See http://rockyweb.cr.usgs.gov/nmpstds/dlgstds.html for the complete document of DLG attributes. Field Definitions: CAT Theme Category PIC Primary Identification Code DSC Descriptive Code WID Road Width LABEL Feature Definition INTERSTATE Interstate Highway Route Number US U. S. Highway Route Number STATE State Highway Route Number MATT Redefined PIC, DSC, and WID Codes into one field SAMPLE .AAT INFO FILE: CAT =17 road category PIC =209 class 3 street DSC =602 overpassing, on bridge WID =999 road width in feet ** REDEFINED ITEMS ** combination of PIC, DSC, and WID MATT =209760999 -------------------- !! ATTENTION !! NEATLINE: designated by PIC and DSC codes of 777 NULL VALUES: '9's are used to fill blank fields -------------------- ** PIC codes for NODES: none ** PIC codes for POLYGON features: none ** PIC codes for LINE attributes: PIC Definition 201 primary route, class 1, symbol undivided 202 primary route, class 1, symbol divided by centerline 203 primary route, class 1, divided, lanes separated 204 primary route, class 1, one way, other than divided 205 secondary route, class 2, symbol undivided highway 206 secondary route, class 2, divided by centerline 207 secondary route, class 2, divided, lanes separated 208 secondary route, class 2, one way, other than divided highway 209 road or street, class 3 210 road or street, class 4 211 trail, class 5, other than four-wheel-drive vehicle 212 trail, class 5, four-wheel drive vehicle 213 footbridge 217 road or street, class 3, divided by centerline 218 road or street, class 3, divided, lanes separated 223 road in service facility or rest area 401 traffic circle 402 cloverleaf or interchange 403 tollgate, toll plaza, or perimeter of toll plaza 732 traffic circle, class 3 ** DSC codes: descriptive code for PIC codes: DSC Definition 601 in tunnel 602 overpassing, on bridge 603 under construction, known classification 605 labeled "old railroad grade" 607 underpassing ** WID codes: width in mils of feature to scale (at 1:24,000) WID Definition WID Definition 650 46-55 feet; 0.025 inches 651 56-65 feet; 0.030 inches 652 66-75 feet; 0.035 inches 653 76-85 feet; 0.040 inches 654 86-95 feet; 0.045 inches 655 96-105 feet; 0.050 inches 656 106-115 feet; 0.055 inches ** Route Numbers INTERSTATE Interstate Highway Route Number US U. S. Highway Route Number STATE State Highway Route Number
The imagery used in interpretation of the road features was 1997 digital orthorectified imagery.
This data was collected from 1-meter resolution orthorectified scanned imagery (1997). The IFSAR imagery was used for horizontal accuracy. The data is revised from the original DLG vector data that was collected at 1:24000-scale within the 40 foot map accuracy standards. See DLG standards at http://rockyweb.cr.usgs.gov/nmpstds/dlgstds.html. The data was collected for government use and represents the results of data collection for a specific activity. USGS makes no representation as to the suitability or accuracy of the data for any other purpose and disclaims any liability for errors that the data may contain. As such, it is only valid for its intended use, content, time, and accuracy specifications. While there are no explicit constraints on the use of the data, please exercise appropriate and professional judgment in the use and interpretation of this data. Acknowledgment of the U.S. Geological Survey would be appreciated for products derived from this data.
U.S. Geological Survey, Rocky Mountain Mapping Center, Denver Federal Center Bldg 810, P.O. Box 25046, MS 516
The final editing and structuring of these data sets were completed by the FRIR project members at the Rocky Mountain Mapping Center.
The attribution for the road data was verified for consistency throughout the demo project area. Check plots were used to compare attribution and spatial extent with the photography. See Part 3, Attribute Coding of Standards for Digital Line Graphs at (<http://rockyweb.cr.usgs.gov/nmpstds/dlgstds.html>) See Entity_and_Attribute_Information and Supplemental_Information sections.
Polygon and chain-node topology present. All areas are closed polygons containing one unattributed label point. All arcs have an attribute code.
Roads feature density consists of all road nets, trails, footbridges and various related features. The region is considered a representative pattern (feature density) with capture conditions according to USGS 1:24000 mapping standards. Use of this data at larger scales may be incomplete. See capture conditions in Part 2-:Standards for Digital Line Graphs and at (<URL:http://rockyweb.cr.usgs.gov/nmpstds/dlgstds.html>)
The road vector data is within 40 ft. to the ground planimetry. The original data is from a mosaic of photorevised 1:24000-scale DLGs derived from stable-base 1:24000-scale USGS topographic maps. Digital orthorectified imagery at a 1-meter resolution was used to collect features. Magnitude imagery from IFSAR (Interferometric Synthetic Aperture RADAR), with a horizontal accuracy of 2.5 meters and vertical accuracy of 2.0 meters, was used to verify horizontal placement of the features. The IFSAR imagery was collected by Intermap Technologies. See National Map Accuracy Standards at (<URL:http://mapping.usgs.gov/standards/>).
Imagery was used to manually interpret and classify the road features.
Interpretation/Compilation - Features were visually identified, interpreted, and classified according to the USGS DLG Limited Update Standards except that data was collected so that 90 per cent of the well-defined features are within 40 ft. to the ground planimetry. The data is interpreted and compiled in blocks of 1:24,000-scale quadrangles. Once completed the data is edge-matched and paneled together into the seamless demonstration area. Final review of the data was to verify attribution, add additional attribution, and move features to geographically match the imagery.
FRIRD items are used to describe the physical and cultural characteristics of line elements. Attribute codes are used to reduce redundant information, provide enough reference information to support integration with larger data bases, and describe the relationships between cartographic elements. See Supplemental_Information section for item definitions. FRIRD.AAT: COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME 1 FNODE# 4 5 B - 5 TNODE# 4 5 B - 9 LPOLY# 4 5 B - 13 RPOLY# 4 5 B - 17 LENGTH 8 18 F 5 25 FRIRD# 4 5 B - 29 FRIRD-ID 4 5 B - 33 CAT 2 2 I - 35 PIC 3 3 I - 38 DSC 3 3 I - 41 WID 3 3 I - 44 LABEL 50 50 C - 94 INTERSTATE 20 20 C - 114 US 20 20 C - 134 STATE 20 20 C - ** REDEFINED ITEMS ** 35 MATT 9 9 I -
CAT Theme Category (DLG Roads = 170) PIC Primary Identification Code DSC Descriptive Code WID Road Width LABEL Feature Definition INTERSTATE Interstate Highway Route Number US U. S. Highway Route Number STATE State Highway Route Number MATT Redefined PIC, DSC, and WID Codes into one field
Rocky Mountain Mapping Center, Denver Federal Center Bldg. 810 Box 25046, MS 516
Contact via email (FAX 303-202-4354)
Although this data has been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of this data, software, or related materials.
Front Range infrastructure resources roads geographic features
Front Range infrastructure resources roads geographic features
ArcIMS Image Map Service
A web-based interactive mapping system that accesses an ArcIMS Map Service running on certmapper.cr.usgs.gov.
Rocky Mountain Mapping Center Denver Federal Center Bldg 810 P.O. Box 25056, MS 516