The following GIS resources will be used by the PathBuilder utility to construct routes for the TrainGear/OSRail railroad simulator:

• DOQQ – Digital Orthophoto Quadrangle – aerial photograph – 1 Meter – UTM - NAD83 – GeoTiff (Geo-referenced Tagged Image File Format) (.tif and .tfw) 250MB
• DRG – Digital Raster Graphic – Scanned Topographic Map – 7.5-minute (24K) – UTM – NAD83 - GeoTiff (Geo-referenced Tagged Image File Format) (.tif and .tfw) 250MB
• NED – National Elevation Dataset – 1 Arc Second Raster - ~30 Meters – Geographic – NAD83 - GeoTiff (Geo-referenced Tagged Image File Format) (.tif and .tfw) tiff is in a32 bit float format – Vertical Meters – NAVD88 250MB
• NLCD 2001 – National Land Cover Dataset 2001– 1 Arc Second Raster - ~30 Meters – Albers Equal Area Conic – NAD83 - GeoTiff (Geo-referenced Tagged Image File Format) (.tif and .tfw) 250MB
• NLCD 92 – National Land Cover Dataset 1992 – 1 Arc Second Raster - ~30 Meters – Albers Equal Area Conic – NAD83 – bil (Binary Integer Point Format) and GeoTiff (Geo-referenced Tagged Image File Format) (.tif and .tfw) 100MB

These resources are available from the USGS Seamless Data Distribution System To download these resource construct a directory tree with doqq, drg, ned, nlcd and image sub-directories. You should strive for the highest resolution of USGS resource that can be downloaded.

• Click on: View & Download United States Data

• Under Zoom (Left side): Zoom down in area (click center of area of interest) until Nation Atlas Railroad appears under Display, Transportation on the right hand tab. Select Railroad, de-select any other and zoom down to a reasonable scale for the terrain you are capturing.

• Select products under “Download” (left side panel), Orthoimagery (DOQQ 1.0m, 24k DRG), Land Cover (NLCD 2001) and Elevation (1” NED).

• Use Download (right side panel) – Define rectangle area to outline the area of to capture. As long as the rectangle is green you have not exceeded the USGS download limits.

• Use “Modify Data Request” in the popup window to get the correct formats (GeoTiff) for the products required. If possible request the NEDs in a large area that includes the higher terrain around the tracks (PathBuilder path). NEDs are small and can be downloaded in large chunks. Request DRG and DOQQ in small chunks immediately around the track path – even then DOQQs may become very large. Large NLCDs can also be downloaded, but the route building function requires only small areas around the track path. DOQQ, DRG and NLCDs can be done as a single operation. The USGS server seems to lose large transitions, so keep rectangles as small as required. If using Internet Explorer, you will have to use the “here” in “If an error occurs during download, click here to retrieve the download bundle” to download the file after an error.