9 replies to this topic

[Dennis McClendon]

I'm working on a page-size map of the Chicago region, and would like to use aerial imagery as a backdrop. But I'm having trouble thinking of a way to get imagery at a scale of 1:100K or smaller. If I use the USGS Seamless server, I can't figure out how to get such a large area—unless I download 100 or more small areas and then put them together.

By far the easiest solution is to just do some screengrabs from Bing (the renamed maps.live.com), but technically I don't have the right to reproduce those. What source am I forgetting about?

[MapMedia]

I'm working on a page-size map of the Chicago region, and would like to use aerial imagery as a backdrop. But I'm having trouble thinking of a way to get imagery at a scale of 1:100K or smaller. If I use the USGS Seamless server, I can't figure out how to get such a large area—unless I download 100 or more small areas and then put them together.

By far the easiest solution is to just do some screengrabs from Bing (the renamed maps.live.com), but technically I don't have the right to reproduce those. What source am I forgetting about?

I use ArcMap and ESRI Microsoft Virtual Earth (trial copy). You pretty much get Google Maps as a layer (aerial, streets, hybrid).

-Chris

[Hans van der Maarel]

15 meter Landsat data? It'll take some work to combine the bands, but it's free. If you don't want to have the hassle, check out TrueMarble, they offer true color versions at a reasonable price. Also, their 250 meter data is free, but too coarse for what you're trying to do.

[Mike Boruta]

You could try the NAIP imagery, though for Chicago it might not be in true color:

http://isgs.illinois...bdocs/naip2004/

[Ed Gage]

If you're using ArcGIS and have access to the data discs they distribute, there is a seamless landsat mosaic layer (150 m) which can work nicely at broad scales. What's nice is that there are no tile boundaries visible, unlike when I've downloaded landsat data from the National Map seamless data server. It is on the "Global imagery and shaded relief: North America and South America" DVD that came with my license for ArcGIS 9.2.

[Matthew Hampton]

I think the NAIP imagery would work out well for you.

It looks like they didn't fly the 1m for '08, but you should be able to get 1m for '07 and they flew 2m in '04-'06.

Here is a link to the NAIP home page.

Here is a link to 2007 DOQQ's from IU

[Dennis McClendon]

Thanks. The NAIP data doesn't cover cities, which is a bit of a problem when the assignment is to map the Chicago area.

Thanks for the various DOQQ suggestions, but that would mean stitching together over a hundred images, right? I was hoping for someplace I could download natural-color photography covering a 100km x 100km area in just a few tiles. Maybe at that scale everyone shifts to satellite imagery.

[Ed Gage]

One last thought...
If you're using ArcGIS, there's the Terraserver extension, which does the work of gathering the tiles you need. For Chicago, I'd assume there would be the "urban area" imagery, not just the DRG and B/W DOQQ. If it's only a page (large or small?), do you need the detail of an aerial vs. something like landsat?

[Dennis McClendon]

I don't need the detail of aerials, but satellite imagery such as Landsat is usually not natural color.

[Mike Vessel]

There is also a nice little software package called Global Mapper (www.globalmapper.com). It has all of the TerraServer download options (Urban Area Higher Res, etc...) and a number of others including Pan-Sharpened Natural Color Landsat7 imagery. It also has a number of nice export options (tiling, pixel size, etc...). You can download the software for free to see if it works for you but I think you have to purchase and register it to export any data. A client initially turned me on to this package a number of years ago. I use it regularly for a variety of purposes and always thought it was an excellent value (in case it's not evident, I'm a fan).

Hope this helps.

Mike