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.