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General Topography

USGS SRTM 1 Second

http://dds.cr.usgs.gov/srtm/version2_1/SRTM1/

Viewfinder Panoramas

http://www.viewfinderpanoramas.org/dem3.html

Bathymetric Data

Shaded Releif / CleanTOP2

Nice bit too low res

http://www.shadedrelief.com/cleantopo2/index.html

CleanTOPO2 comes in three versions tailored to meet different design and production needs. All versions are 16-bit grayscale TIF files measuring 10,800 x 5,400-pixels and include a World (.tfw) file and "Read me" document with projection and datum information. The Geographic projection is used. All data available here are in the public domain.

NGDC / Global Land One-km Base Elevation (GLOBE) Project

http://www.ngdc.noaa.gov/mgg/topo/gltiles.html

BODC / GEBCO Digital Atlas

https://www.bodc.ac.uk/data/online_delivery/gebco/ https://www.bodc.ac.uk/data/online_delivery/gebco/gebco_08_grid/

  • a global 30 arc-second grid of global elevations; it is a continuous terrain model for ocean and land.
  • 1.8 GB unzipped. Data is in netCDF format. Don't know how to read this yet

Released: September 2010

  • generated by combining quality-controlled ship depth soundings with interpolation between sounding points guided by satellite derived gravity data. A ‘source identifier’, SID, grid is also available to download to accompany the GEBCO_08 Grid. This shows which grid cells have been constrained by bathymetry data during the gridding process.

From PDF:

Within the netCDF files for the GEBCO_08 Grid and GEBCO_08 SID Grid, the data are stored as one-dimensional arrays of 2-byte signed integer values. The complete data sets give global coverage and each file consists of 21,600 rows x 43,200 columns, resulting in 933,120,000 data points. The data start at the Northwest corner of the files, i.e. for the global files, position 89° 59’ 45’’N, 179° 59’ 45’’W and are arranged in latitudinal bands of 360 degrees x 120 points/degree = 43,200 values. The data range eastward from 179° 59’ 45’’W to 179° 59’ 45’’E. Thus, the first band contains 43,200 values for 89° 59’ 45’’N, then followed by a band of 43,200 values at 89°59’ 15’’N and so on at 30 arc-second latitude intervals down to 89° 59’ 45’’S. The data values are pixel centre registered i.e. they refer to data values at the centre of grid cells.

credit: ‘The GEBCO_08 Grid, version 20100927, http://www.gebco.net’.

Satellite Geodesy research group at Scripps Institution of Oceanography, University of California San Diego

http://topex.ucsd.edu/WWW_html/mar_topo.html ftp://topex.ucsd.edu/pub/srtm30_plus/topo30/ ftp://topex.ucsd.edu/pub/global_topo_1min/ << has img files

2014-03-27 ~ Looks like a good data set to use as the base

Latest update: 2013-12 SRTM 30 second ~1km ~120 data points/degree Data are in SRTM format - readable with Jaanga HGT viewer

The pixel-registered data are stored in 33 files with names corresponding to the upper left corner of the array shown below. The data are also merged into a single large (1.9 Gbyte, 2-byte integer) file as well as smaller 1-minute and 2-minute netcdf versions. Matching files of source identification number are available for determining the data source for every pixel.