[Talk-us] [Talk-ca] USGS Orthos in Canada

[Ian Dees]

Hi Richard and Stewart,

I run the OSM US server that's serving these tiles for you. Answers are
below:

On Thu, Aug 9, 2012 at 4:39 PM, Richard Weait <richard at weait.com> wrote:

> We should be asking about this on talk-us.  cc'd there.
>
> On Thu, Aug 9, 2012 at 8:17 AM, Stewart C. Russell <scruss at gmail.com>
> wrote:
> > While editing near Leamington ON in Potlatch, I clicked by accident on
> > the Background -> "OSM US USGS Large Scale Aerial Imagery". It came up
> > with really sharp and recent orthoimagery. It's of similar quality to
> > the SWOOP images I buy at $50/km^2 for work, and covers some areas that
> > Bing doesn't. Images look to be from 2010 or so, guessing from the
> > visible wind power projects in SW Ontario.
> >
> > Trying out several areas near the US border I found:
> > * that coverage is seemingly random; some isolated areas have it,
> > contiguous areas near the border might not
>

Coverage should be relatively consistent: when you're over an area that has
high resolution imagery it will use it, otherwise it will use the most
recent NAIP imagery. I see a relatively consistent image along the entire
US/Canada border.


> > * it's coming from a very slow server which only works if you're zoomed
> > in very close
>

The URL you're hitting leads to a CDN that has been having a hard time
lately. Also, the server simply caches imagery requests to the USGS server
which can get busy during the day.


> > * it's not seemingly available from a public WMS, as any of the USGS
> > servers I tried blank at the Canadian border.
>

The data comes from here:
http://raster.nationalmap.gov/ArcGIS/rest/services/TNM_Large_Scale_Imagery/MapServer


> >
> > Surprisingly, it seems that not all USGS imagery is public domain
> > (
> https://wiki.openstreetmap.org/wiki/USGS_High_Resolution_Orthoimagery#Data_License
> ).
> > So, can we use it?


All imagery in the list referred to by that page is marked "public domain".
Yes you can use it.
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