BigTopo Tour:

BigTopo the All Topo Maps seaming tool

Have you ever had a project or trip that falls right on the edge or the corner of four maps? Would you like a single topographic map that covers a huge area? Do you need a large coverage map that you can use in another CAD or GIS application?

BigTopo combines multiple quadrangles (7½ minute 1:24,000 scale and 1:63,360 scale Alaskan maps) to generate large coverage areas. Single, full-resolution maps can be generated that cover up to 5,930 square miles (77 miles in height and width - Win95/98 machines are limited to 1/4 gigabyte images.)

BigTopo can optionally add borders, a scale, UTM and Lat/Lon grids. BigTopo will even export maps to generic raster formats like .BMP, .TIF and .PNG. All exported map images may be used without copyright issues for any use.

BigTopo is included at no additional charge in most All Topo state sets, and it is available as by free web update to existing customers from the All Topo Update Center.

BigTopo will quickly take maps like these:

and generate new coverage areas like this:

Huge area coverage can also be generated:

This image covers an area 72 miles wide and 4 miles high, from Delle (West of the Great Salt Lake, near Salt Lake City Utah) to Parley's Park (North of Park City, Utah). Portions of 22 quadrangles are included in the image. The .bmp image produced by BigTopo is 36,116,498 bytes and includes the full 160 DPI AllTopo resolution, click on the thumbnail below to see a full-sized portion of the image's center:

Files exported to generic graphics formats include worldfiles (.TFW extension for .TIF exports) so that other GIS applications can automatically open BigTopos fully georeferenced. This means you can use seamed All Topo Maps as raster images in most GIS and CAD-Map applications.

See [ Using BigTopos in GIS/CAD ] for more information.

Building a BigTopo map is easy to do. This tour will take you through these easy steps:

1. Define BigTopo Map Coverage

Start the All Topo Maps viewer and find the center location of the BigTopo map you want to make:

Put the cursor at the spot you would like centered on the final BigTopo. Press Control-X to copy the current cursor location to the clipboard. (Press and hold the Control key, then press and release the X key, finally release the Control key.)

In the example above the coordinate: "N 38 37 30.123 W 109 22 30.110" is placed in the Windows clipboard.

2. Start BigTopo

BigTopo is a separate application, you will find it under the Tools option in the All Topo Maps viewer

BigTopo will load 

Press the 'Get Coordinate' button on the center of the dark gray box (the button with the gold spike and black bombsight) to paste the coordinate held in the Windows Clipboard to the resulting map's center location:

Finally change the Height to 2.0 miles and Width to 3.0 miles:

3. Choose the Annotations and Output File Name and Path

Select the 'Annotations' tab:

Choose if the resulting BigTopo map will be re-collared.  Collared maps can be annotated with a map name, a scale, UTM and Lat/Lon grids.

Finally, select the 'Output File' tab:

To make a map compatible with the All Topo viewer, choose 'Output BigTopo to All Topo Maps', press the 'Browse...' button to enter a filename for the resulting map. 

Enter output file named 'test' (1), then press 'Save' (2) to set the BigTopo's filename.

If the Big Topo you are making is for use in another application select 'Export Big Topo as generic graphics picture'. More details can be found below [ Using BigTopos in CAD/GIS ]

4. Make the BigTopo.

Select the 'Build Big Topo' tab:

Information about the resulting BigTopo map is displayed, press the 'Make Big Topo' button to start building the requested BigTopo map. The 'Activity Log' is automatically displayed while the map is generated:

at the completion of the BigTopo generation, the 'Build BigTopo' tab will be shown again.

5. Preview the Seamed Map in BigTopo.

Press the 'Preview test.it3' button found on the 'Build BigTopo' tab to view the new BigTopo map:

Use the PageUp and PageDown keys to zoom in and out, press the shift key to use the magnifying glass (as shown the picture above) to closely inspect the seamed map. When you are all previewing the BigTopo, use the menu option 'File: Close Preview' to return to the main BigTopo screen.

6. Opening the BigTopo from All Topo Maps

Use the Window's 'Change Task' shortcut keys Alt+Tab or the Windows Task Bar to return to the All Topo Maps viewer, then select 'Open BigTopo Map' from the File menu:

The 'Open BigTopo Map' dialog is shown:

Choose 'test.it3' with your mouse, then press Open. The newly created BigTopo is shown and any active annotations are overlaid on the map:

For use with ESRI(r) Arc(r) products ("ESRI and 'Arc' are trademarks of Environmental Systems Research Institute, Inc.") select  'Export BigTopo as generic graphic picture' and 'Browse...' for a path and filename to write the resulting BigTopo image too. A .TFW world file will be written to the same path and file name (C:\AllTopo\BigTopo\TestBT.TFW for this example). When the .TIF file is added as a theme, the .TFW file will automatically dereference the image map image.

Sample BigTopo's (.TIF, .TFW, .TXT files) are provided in compressed form [ Sample Images ].

To import an image to AutoCad(r), select 'Export BigTopo as generic graphic picture' and 'Browse...' for a path and filename. Choose to export a .BMP file, a .TXT file will also be written to the selected path and filename. Open the companion .TXT file (TestBT.TXT) with Notepad and find the CAD insertion information within the .TXT file:

; CAD base insertion and scale include map collars (entire image).
CAD Insertion Point (SW Corner) = 413,954.24M E, 4,508,058.19M N, Z 12 (UTM Meters)
CAD Horz Scale = 3,219.450 (Meters); 10,562.500 (Feet)

Finally select the CAD menu option 'Insert: Raster Image', place the image manually or at the enumerated 'CAD Insertion Point'. When prompted for the image's scale factor, use the 'CAD Horz Scale' (the image's width in engineering units).

Note 1: The CBM image was generated as an All Topo Maps native .IT3 file. The BigTopo was opened in All Topo Maps, Coal Bed Methane annotations were downloaded from the Wyoming Oil and Gas Conservation Commission's web site [ see WOGCC ] and the BigTopo was exported using the All Topo Map Export Wizard to a .TIF file with a worldfile.