forwarded usgs ...
-------- Original Message --------
Subject: Fw: DOQQ's
Date: Wed, 5 Dec 2007 17:42:39 -0500
From: John C Fouke <[log in to unmask]>
To: maps-l
I received an interesting inquiry recently that asked "Is there any place
in the US (lower 48 and Hawaii) that does not have 1:12,000 scale DOQQ's
available?". Below is the answer that Steve Reiter at the USGS Denver
SILS put together:
Greetings: I just spoke with Dan Daniels - he's our Orthoimagery
Manager. Dan said all of the lower 48 states should be available as DOQ
quarter-quads. There may some locations that are blacked out or reduced
in resolution due to security concerns. The USGS seamless website offers
up this imagery for free download (see the attached word document
"Seamless.doc"). For unknown reasons, there's been a gap in coverage in
the northwestern part of Maine, but Dan says this area will soon be
downloadable as well.
I checked the USGS EarthExplorer website (
http://edcsns17.cr.usgs.gov/EarthExplorer/) for DOQ coverage of Hawaii &
Alaska. This website serves as our sales database, so it should be an
accurate reflection of available coverage. Unfortunately, the results
are reported as text, not as a pictorial image. There are 271
quarter-quads available for Hawaii. There are 581 quarter-quads available
for Alaska. I believe there are gaps in the Hawaii coverage and I'm
certain there are gaps in Alaska coverage.
John Fouke
text instead of attachment:
*http://seamless.usgs.gov*
The USGS seamless website offers free digital data suitable for import
into a Geographic Information System (GIS). If you don’t have a
reasonably fast Internet connection, you’ll probably find this to be a
frustrating experience. If you are using Windows XP and have Service
Pack 2 installed, you’ll want to look at the first
Frequently-Asked-Question from the dropdown menu – it details how to
configure Windows XP so downloads from the seamless website are
permitted. It’s a good idea to read all of the FAQs before proceeding.
You may download United States data as well as world data – choose the
appropriate panel. A new screen appears with tools on the left, a map
interface in the center, and layer information on the right. By default,
the zoom-in tool is active, so with each click, you’ll see more detail
and features like roads, political boundaries, and place names will
begin to appear. By default, the “layer” tab is active on the right. You
may turn layers on & off under the layer tab to help you identify your
area-of-interest (AOI); notice each layer can be expanded & contracted
by clicking on the arrow.
Once zoomed to a sufficient resolution that displays your AOI, click the
“download” tab on the right. By default, the 1-second NED layer is
checked, meaning that’s the layer you wish to download. If appropriate,
uncheck that layer & choose another. Note you may check several layers
for download. Data availability is not uniform: some areas will have
layers that are not available at other geographic locations and vice-versa.
Once the appropriate layer(s) is selected, you need to define a download
area. On the left, the “Downloads” grouping of tools offers several
options. For most users, the “Define Download Area” and the “Define Area
by Coordinates” tool is appropriate; the first allows you to drag a box
– a green box is permissible, a red box exceeds the file size capacity.
From here, the process is straightforward. Data will be served up as
zipped files for transfer. Some data is available in several different
formats; to change the default format, click “Modify Data Request” on
the SDDS Request Summary Page. If you request a large block of data,
layers may be parsed into a number of smaller files to download.
Some users have expressed a preference for the Internet browser
“Mozilla Firefox” when using the Seamless website. The browser is
available here:
http://www.mozilla.com/en-US/firefox/
This is provided for informational purposes only and does not constitute
endorsement by the US Geological Survey.
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