Wow this is huge news. I wonder what higher resolution the DoD now has at their disposal to prompt them to release this.
For any potential consumers of the data, be aware the SRTM has significant gaps in coverage: nothing above latitude N61 or below S56, and also extensive voids in mountainous areas (typically the most interesting part!) and also in deserts.
This guy [http://www.viewfinderpanoramas.org/dem3.html] (90's web design notwithstanding) has done amazing work in filling these gaps to turn SRTM into a truly global dataset. I wonder if he's kicking himself that he's now about to sink another few years of his life upgrading everything to 1".
Nice work with the 'Oilslick' elevation ramp. That provides for some very neat spatial pattern recognition/identification. I don't think I've seen anything quite like that before.
>> Wow this is huge news. I wonder what higher resolution the DoD now has at their disposal to prompt them to release this.
I would love to know what the DoD are achieveing with high res synthetic apeture radar imagery. It has some really amazing properties (like measuring tiny changes in elevation) that are barely exploited commercially. The ability to track everything though cloud cover has obvious military applications.
oilslick is really neat, I find it both pleasing to look at and actually useful to view the full elevation range. Is there any common geospatial software that includes oilslick out of the box?
Now it would be great to integrate this data into OSM to get navigation for bikes that takes slopes into account: this is the shortest route, this is the fastest considering slope, this is the sportiest…
SRTM data is nearly useless for that purpose. I had a run at this exact application a few years ago and it was quite an exercise in frustration. The resolution of the data is adequate, but there are artifacts related to the way the data was collected and processed. There are discontinuous edges throughout the data. Also, of course, the data is not the elevation along a route. Bridges and other things over or under which one might ride a bicycle must be accounted for externally. Even roads in trenches or cuts need special attention.
I think the only way to make such an application work is to combine the elevation data of numerous sources, SRTM being just one. The most valuable source would be the ambient pressure sensors in mobile phones, which are next to useless for absolute altitude but are excellent for relative altitude as you move along a path, and of course they have GPS so you also know the path taken.
cycle.travel/map is really nice. I remember there was (years ago) a nifty cycling map of the city of Atlanta, which included a unique triangular control that allowed the user to trade off climbing vs. distance vs. safety (on-road or off, bike lanes, etc). It was based on Google tiles and routes but had its own elevation data.
Not that I'm trying to discourage anyone from solving this problem. That was merely my experience. There probably exists some combination of filtering and cleverness that would get around the discontinuities. But I think you can see from Google's incredibly vague elevation-along-route bike directions that this problem is not easy.
The US govt has also been relaxing the export restriction on high-resolution imagery as well.
DoCommerce gave digital globe permission to sell 0.31 m for b&w band and 1 m for multispectral bands from WorldView-3 beginning in Feb 2015 I think.
EDIT: http://worldview3.digitalglobe.com added link to microsite. Couldn't find quick link to relaxing of export restrictions but I am 99% sure it was announced months ago.
High-resolution elevation data from the Shuttle Radar Topography Mission-Level 2 (SRTM-2), previously only available for the United States, will be made publicly available over the next 12 months
::it will be available to everyone and will be released in the next year::
It's been available via FTP for at least 7 years. Perhaps they are now releasing some version that's higher resolution than the prior 1", 65GB tile dump.
The date in the data version history is "02/14/05" for this release.
For any potential consumers of the data, be aware the SRTM has significant gaps in coverage: nothing above latitude N61 or below S56, and also extensive voids in mountainous areas (typically the most interesting part!) and also in deserts.
This guy [http://www.viewfinderpanoramas.org/dem3.html] (90's web design notwithstanding) has done amazing work in filling these gaps to turn SRTM into a truly global dataset. I wonder if he's kicking himself that he's now about to sink another few years of his life upgrading everything to 1".
If anyone wants to casually peruse the (old 3") data, I found a rather nice rendering here [http://maps-for-free.com/], and was inspired to do my own take [http://mrgris.com/projects/oilslick/].