Mapping software

[DougPaul]

Doug, what do you do with those Libre maps? I called one up at random and it’s just a bunch of speckles. I don’t see any way to zoom in on it, and I don’t have any way of printing 30x40 sheets, or whatever it would take.

The USGS topo files are generally in TIFF format. TIFF is just a graphics format, similar in purpose to a JPEG. (The details differ, but no need to worry about them here.) You should be able to display them with a picture display program that supports the TIFF format. Xv and display (part of the ImageMagick package) will work in a *NIX environment, one of the PC or Mac users will have to chime in for those environments.

Note: xv will scale the image to fit on the screen. This will cause a significant scaling down of the image and it may not show well. Display will keep the original scale, show you only a section which will fit on the screen, and allow you to scroll around to see various sections. Thus display (or something similar) is a better tool for this purpose.

Note: just checked--the ImageMagick package, including the "display" viewer is available for PC and Mac environments: see http://www.imagemagick.org. It is open-source software and is free of charge.

For instance, download the Boston North quad: http://ia331328.us.archive.org/1/items/usgs_drg_ma_42071_d1/k42071d1.tif. This is a 9722x6203 (60M) pixel image--possibly too large for some viewers. In general, you should be able to display it with an appropriate image viewer. You can use an image editing tool to crop out a smaller section and/or change the scale for printing.

I just tested the above file--it works on Linux as I have stated. I'm sure appropriate tools exist in the PC or Mac environments.

Doug