Hi Barend, Thanks for the observations and grumbles! I was thinking of giving the observer three choices: (1) the one I've got now: a ratio of the region's value to the maximum value on the scale, which in the case of some variables overly condenses the chromatic range (2) a measure which calibrates the value map according to a region's value relative to min = light and max = dark and (3) one that merely rank orders the regions by value The last would maximize visual discrimination of subtleties, while obscuring quantitative magnitudes. I think (2) is probably what most maps do, so would that make sense as a default presentation? It is sort of philosophically between (1) and (3) .
Ultimately, I'd like the observer to be able to choose her own "data spigot" from any URL on the web that presents a column of state-related data in easily parseable form, or to meta-mine search data for queries like "alabama shoes" through "wyoming shoes" from a search engine, to make the shell infinitely extensible, but am trying to get permission from search providers for such meta-mining. I'll have to figure out a way to find the real estate for the title on screens with "funny" aspect ratios. A fun thing about this is how little server-side script there is, just ten lines, and requiring just one linear pass of the dataset per user-chosen variable -- that should, in theory, make it fast and extensible to very large datasets. My understanding is that PHP caches a lot of the memory so that reuse of the same data source may be optimized server-side: <?php $f="/mydatafile"; $o=file($f); $data=""; for ($i=0;$i<count($o);$i++){ $line=explode(",",$o[$i]); $data=$data.$line[$num].","; } echo $data; ?> best, David --------- PS I'll need to learn a bit of an introduction to the cartographer's art and science, since I suspect I'll be in over my head next semester. Tips like this are sought! ----- Original Message ----- From: "Barend Köbben" <kob...@itc.nl> To: <svg-developers@yahoogroups.com> Sent: Tuesday, November 23, 2010 2:47 AM Subject: Re: [svg-developers] US Map with US Census data Nice. <cartographer grumble> don't use a value map (choropleth) for absolute values (data of measurement level ratio), Its perception properties makes for confused readers... </cartographer grumble> :-) as an example of the power of SVG (for which I am sure it was meant), it is of course excellent. Note that on a display with portrait ratio the map is obscuring the title. Yours, -- Barend Köbben (Senior Lecturer) ITC - University of Twente, Faculty of Geo-Information Science and Earth Observation PO Box 217, 7500AE Enschede (The Netherlands) +31-(0)53 4874 253 From: ddailey <ddai...@zoominternet.net<mailto:ddai...@zoominternet.net>> Reply-To: "svg-developers@yahoogroups.com<mailto:svg-developers@yahoogroups.com>" <svg-developers@yahoogroups.com<mailto:svg-developers@yahoogroups.com>> Date: Sun, 21 Nov 2010 22:12:52 +0100 To: "svg-developers@yahoogroups.com<mailto:svg-developers@yahoogroups.com>" <svg-developers@yahoogroups.com<mailto:svg-developers@yahoogroups.com>> Subject: [svg-developers] US Map with US Census data Here's a little something I cobbled together in the past couple of days. http://granite.sru.edu/~ddailey/usmap.svg It works in Opera, Firefox, Chrome and Safari, but not in ASV(IE). I've not tested it in IE9, but would be interested to know if it works there. I took a gnu-licensed SVG map from Wikimedia Commons and then wrote AJAX and JavaScript and PHP to take data from the US Census bureau's 82 variable set, shading the states accordingly. After a variable is chosen then you can mouseover each state to see its numeric value on that variable. Since it borrows from something with a GNU license I suppose you can't make profit out of it, but feel free to improve and share! cheers David [Non-text portions of this message have been removed] Faculty of Geo-Information Science and Earth Observation (ITC) University of Twente Chamber of Commerce: 501305360000 E-mail disclaimer The information in this e-mail, including any attachments, is intended for the addressee only. If you are not the intended recipient, you are hereby notified that any disclosure, copying, distribution or action in relation to the content of this information is strictly prohibited. If you have received this e-mail by mistake, please delete the message and any attachment and inform the sender by return e-mail. ITC accepts no liability for any error or omission in the message content or for damage of any kind that may arise as a result of e-mail transmission. [Non-text portions of this message have been removed] ------------------------------------ ----- To unsubscribe send a message to: svg-developers-unsubscr...@yahoogroups.com -or- visit http://groups.yahoo.com/group/svg-developers and click "edit my membership" ----Yahoo! Groups Links ------------------------------------ ----- To unsubscribe send a message to: svg-developers-unsubscr...@yahoogroups.com -or- visit http://groups.yahoo.com/group/svg-developers and click "edit my membership" ----Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/svg-developers/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/svg-developers/join (Yahoo! ID required) <*> To change settings via email: svg-developers-dig...@yahoogroups.com svg-developers-fullfeatu...@yahoogroups.com <*> To unsubscribe from this group, send an email to: svg-developers-unsubscr...@yahoogroups.com <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/