[Talk-us] USGS imagery (was: Changeset 5393406)

Alan Mintz Alan_Mintz+OSM at Earthlink.Net
Fri Aug 13 05:39:23 BST 2010

At 2010-08-12 21:17, Eric Wolf wrote:
>I know this seems like a silly question, coming from me and all, but where 
>are you getting your NAIP tiles from?

Kinda glad you asked (someone else). There are some issues.

1. Microsoft-Terraserver-now-MSRMaps-hosted "Urban" imagery set is 
0.25m/pel, pre-2005, is quite well-aligned (probably within ~1m), but only 
available for parts of some urban areas:


This is my personal fav for southern CA, where available. It's highest res 
imagery I can find available for JOSM, since the Yahoo imagery we can get 
is only the old 1.6m/pel stuff, and not what they serve on maps.yahoo.com 
(some of which is down in the 0.10-0.15m/pel range).

2. Someone posted to the list recently the USGS NAIP 1m/pel source:


which is better than the 1.6m Yahoo, but still not great in high-density 
urban areas, or where you need higher res to deal with partial tree cover.

3. Then there's the HRO stuff like:


Generally ~0.3m/pel and 2006-2009, which is good, but you have to spend 
some time finding and adding links to your viewer for the areas you are 
interested in. At some point, JOSM doesn't have enough menu space. Also, 
some of them (like the one above) are somewhat mis-aligned, maybe by 3-5m 
in places. There is also a strange "tearing" that has the effect of making 
straight lines look "wobbly" that may be related. It would be nice to be 
able to talk to someone about exactly what's happening here.

It sure would be nice if these individual image sets were available through 
a common interface, instead of having to find/add all the separate links.

Alan Mintz <Alan_Mintz+OSM at Earthlink.net>

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