A note about data scale:
Scale is an important factor in data usage. Certain scale datasets are not suitable for some project, analysis, or modelling purposes. Please be sure you are using the best available data.
1:24000 scale datasets are recommended for projects that are at the county level. 1:24000 data should NOT be used for high accuracy base mapping such as property parcel boundaries.
1:100000 scale datasets are recommended for projects that are at the multi-county or regional level. 1:125000 scale datasets are recommended for projects that are at the regional or state level or larger.
Vector datasets with no defined scale or accuracy should be considered suspect. Make sure you are familiar with your data before using it for projects or analysis. Every effort has been made to supply the user with data documentation. For additional information, see the References section and the Data Source Contact section of this documentation. For more information regarding scale and accuracy, see our webpage at: <http://geoplan.ufl.edu/education.html>
- As new streets are reported, they are added daily by digital map technicians (DMTs) working in teams assigned to specific geographic areas covering the entire nation. As DMTs work through their particular regions, they concentrate on areas that contain the largest numbers of missing addresses, usually newly developed areas. They apply address ranges to unaddressed street segments, digitized new streets, correct inaccurate segment shapes, and add exits and turn or one-way restrictions. Each addition is verified with current maps and other data.
- For line segments that originated with the USGS DLG-3 files, the FCC is based on the USGS classification code in the DLG-3 file. For line segments that originated with the 1980 GBF / DIME Files, the FCC is based on the NS code and other feature identification content of the GBF/DIME -File.
- Latitude/longitude Data: except for DIME format (ASCII) boundary files, all latitude and longitude coordinates are signed and have six decimal places. Northern latitude is positive (0 degrees to 90 degrees), southern latitude is negative (0 degrees to -90 degrees). West longitude are negative (0 degrees to -180 degrees), and longitude are positive (0 degrees to 180 degrees)
- DIME format boundary file coordinates are expressed as all positive values with six implied decimal places. Any longitude west of 180 degrees is expressed in increasing, rather than decreasing values.
·Projection using latitude/longitude coordinate values with an implied 6 decimal places
·All coordinates are based on the 1983 North American Datum (NAD83).
- As new streets are reported, they are added daily by digital map technicians (DMTs) working in teams assigned to specific geographic areas covering the entire nation. As DMTs work through their particular regions, they concentrate on areas that contain the largest numbers of missing addresses, usually newly developed areas. They apply address ranges to unaddressed street segments, digitized new streets, correct inaccurate segment shapes, and add exits and turn or one-way restrictions. Each addition is verified with current maps and other data.
- ARC/INFO format products are available in double precision. Precision refers to the number of bits (single - 32bits, double - 64 bits) used to store coordinate data. Coverages in double precision are slightly more accurate, but larger than those in single precision.
·For more detailed information please see Geographic Data Technology Inc. 1(800) 331.7881 or email to info@gdt1.com
Process Steps for NTAD 2003 Intermodal Facility Locations:
-Intermodal Facility locations were obtained from the CD-ROM National Transportation Atlas Database (NTAD) 2003 (A Collection of Spatial Data for Use in GIS-based Applications) BTS-03-04. -GeoPlan extracted this data in shapefile format and removed facilities not located in Florida. -Three tables were also joined to the shapefile through the Facilities ID number. -The shapefile was reprojected from WGS_1984 Decimal Degrees to the FGDL Albers HPGN map projection. (See "Map Projection Parameters" below).