The Zombie Stack Exchanges That Just Won't Die
I have a growing library of environmental and economic spatial data. Some sets cover the earth for decades, others are localized and span a few months. On a landing page, what are effective ways to communicate this range of possibilities to my users?
Some will be experts and some will be seeing GIS interfaces for the first time. I want to provide an interface that inspires more exploration than a simple table would.
Matt Stephenson
In this case, I think the "how much" is less important than the "how displayed." There's quite a lot of impressive GIS landing-page design out there. For a good example, try this interface to the David Rumsey map collection. For a less-good one (sorry, UConn, not picking on you, honest!) try this layout, which is quite common and quite horrible.
It really depends on what type of spatial data it is.
I typically group things into one of three categories:
For #3, I believe the norm for images of the Earth is the FDGC standard, which is being rolled into ISO 19115. (if it's not on Earth, you'd want to use WCS (World Coordinate System)).
I'm not sure on the other two, but I'd look at OGC (Open Geospatial Consortium), although I think they're more interested in web services to retrieve data.
For interfaces, for #2 (and maybe #1), I'd look at something like Socrata OpenData which is being used by data.gov (map example), where you can switch between tabular view & points on a map.
For #2 and #3, I believe you can put them into KML and use Google Earth (or NASA World Wind) to overlay them (it might support #1, too) I've seen some really cool visualizations of atmospheric data taken by planes, where they had it so you could 'watch' the plane's flight (and view it from different angles as it looped around).
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As for showing people what you have ... I'd be inclined to do a map-like interface, with markers on it showing what places you have data about. You might put some other controls to filter it down (by date, by type of data), which would reduce the number of markers on the map.