Subject:
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Re: New World LUG Map demo
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Newsgroups:
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lugnet.admin.general
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Date:
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Fri, 28 Mar 2003 00:22:31 GMT
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Viewed:
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188 times
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In lugnet.admin.general, Ken Koleda writes:
> A few questions and comments.
> - What is your source for the country polygons?
A public domain ESRI .e00 file from GRID or NOAA, I forget which.
> - You are coding all the map generation? You have your own code writing
> the SVG?
ya
> I have been recently working with a program called SVGMapper. Well, it's
> an extension really.. an extension to ArcView from ESRI.
> Here is a test sample:
> http://rougeriver.com/svgmaps/cso_comp/map.htm
> While this doesn't look much like what you have, it may give you some ideas.
I realize how popular ArcView is, but I avoided it because I need things to
run on Linux and FreeBSD (and also because of licensing issues, since it's
a commercial product). I also needed low-level ASCII representations of the
polygons if I was to have any hope of understanding and customizing what was
going on. So I searched and searched and eventually found a public domain
dataset in a format that I was able to transmogrify into something usable for
my purposes.
> Also, the program that generates the SVG has an option, which I've used,
> to compress the files. It uses (freeware?) called gzip. One hassle is
> that the .SVGs are no longer readable text. But, with my data sets the
> files go down by about 2/3rds in size. Helpful for folks on dialups.
Ya I'm piping all the SVG data through gzip -9 and writing out .svgz files
to the SVG output cache and seeing about 5.7x compression on average.
> - Some where on there you should have the instructions on how to zoom, pan
> etc,
Good idea...although before encouraging zooming in, there probably needs to
be a way to force an overly detailed map (with the default being as it is
currently, which is to include _just enough_ detail for the intended view).
Right now, if you zoom way in on a full-world image, you'll see really low-
resolution polygons, whereas if you generating a map that's specially zoomed
in from the start, it uses higher resolution data. This is simply to reduce
bandwidth as much as possible. The full world view at full resolution is
more than a megabyte even after gzip compression, making it unsuitable for
a general entry page.
> "zoom = control+left mouse" for example
I'd hate to Mac OS X users to Ctrl-click or Windows users to press Command-
click. Maybe it could guess what hardware they're running on from the user-
agent string their browser sends. :)
--Todd
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Message has 2 Replies:
 | | Re: New World LUG Map demo
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| Many years ago (maybe 1986) I wrote some of the simple projection routines for a little mapping project.. I think it was some sort of independent study. While I was unaware of the Free BSD and linux issues, I wasn't intending to propose ArcView due (...) (22 years ago, 28-Mar-03, to lugnet.admin.general)
| | | Re: New World LUG Map demo
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| Hi Todd, (...) I'm happy that you point that two OS. I've tried to have SVG working under Linux RedHat 7.3 and Mozilla 1.0.1 without success. The plugins that are on Adobe web page are from 2001 and have been developped for Mozilla 0.99 and they (...) (22 years ago, 28-Mar-03, to lugnet.admin.general)
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Message is in Reply To:
| | Re: New World LUG Map demo
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| Todd, A few questions and comments. - What is your source for the country polygons? - You are coding all the map generation? You have your own code writing the SVG? I have been recently working with a program called SVGMapper. Well, it's an (...) (22 years ago, 27-Mar-03, to lugnet.admin.general)
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