"SRTM_to_STL" was my first attempt at writing a Python suite to convert NASA SRTM data (3 arc-second spacing) into STL files for 3D printing Then NASA released the much better SRTMGL1 1 arc-second data set... The intermediate .csv files used by SRTM_to_STL couldn't easily handle the x9 increase in data, so I re-wrote the code to use intermediate numpy .npz files instead The SRTMGL1 data can be downloaded from: http://earthexplorer.usgs.gov/ (select the data set called "NASA LPDAAC Collections \ NASA SRTM (SRTM 3) Collections \ NASA SRTM3 SRTMGL1") The 1 arc-second data has a horizontal resolution of about 30m on the ground and is best suited for printing relatively small areas at maximum resolution. You can still join the hgt files together if the area you are interested in crosses file boundaries, but the software will then ask you to cut the data leaving 3601 x 3601 points If you want to print large areas, you will probably be better off using "SRTM_to_STL". You can still use the 1 arc-second data, just use SRTM_resample.py to convert the 1 arc-second data files into 3 arc-second. To create a nice print of the summit of Everest: Everest straddles N27E086.hgt and N28E086.hgt, so use SRTM_Join.py to join the files together: python SRTM_Join.py N27E086.hgt N28E086.hgt The code will ask you which row you want to cut from. Enter "1800" You need to keep a note that the file now has a latitude offset of 0.5 degrees SRTM_to_NPZ.py then converts the hgt file into numpy .npz format: python SRTM_to_NPZ.py N27E086_join.hgt The npz file contains: width, height, hgt_max, east, north, hgt Where: width is the width of the data in eastings (columns) height is the height of the data in northings (rows) hgt_max is the maximum altitude in the data east is the array of eastings north is the array of northings hgt is the array of altitudes UK data is converted to OSGB coordinates using WGS84toOSGB36 Data for the rest of the World is converted to UTM The npz file can then be trimmed to our area of interest: python NPZ_Trim.py N27E086_join.npz 487000 496000 3091700 3100700 (This trims the npz file to a 9km x 9km area centred on the summit) (The trimming takes a long time - there must be a more efficent way of doing it!) The .npz file is then converted to .stl: python NPZ_to_STL.py N27E086_join_trim.npz 87.5 90.0 Enter 0.0 for the base offset and base thickness to create a true 1:100,000 scale print. You can save plastic by entering a base offset of -50.0. slic3r or MeshLab will display the STL file, but if you want to view it using Python and Mayavi you can: python 3D_STL.py N27E086_join_trim.stl The hgt filename refers to the lower left pixel or sample in the data Sample spacing is 1 arc-seconds for SRTMGL1 data Data is two byte signed integers (big endian) First row in the file is the ***northernmost*** one utm has been gratefully plagiarised from https://pypi.python.org/pypi/utm and then modified to allow the UTM zone to be forced. This is essential if the hgt data crosses or ends on a UTM zone boundary. See http://www.dmap.co.uk/utmworld.htm WGS84toOSGB36 is gratefully plagiarised from: http://hannahfry.co.uk/2012/02/01/converting-latitude-and-longitude-to-british-national-grid/ If you have enjoyed this code, please make a small donation to Keswick Mountain Rescue Team: http://www.keswickmrt.org.uk/support_us.htm http://www.keswickmrt.org.uk/