<html>
<head>
<style><!--
.hmmessage P
{
margin:0px;
padding:0px
}
body.hmmessage
{
font-size: 10pt;
font-family:Tahoma
}
--></style></head>
<body class='hmmessage'><div dir='ltr'>
Nice wording, Steve.<br><br>This is why YAAC keeps the OpenStreetMap data in vector format and renders it "on-the-fly" for the desired viewport (window size, map center, and zoom level). It may be computationally costly, but it is accurate. Since I've added the USGS topographic data (which is raster elevation data), you can see the graininess of it when you zoom in deeply.<br><br>And, alas, vectorization of raster maps is highly error-prone and requires manual corrections.<br><br>Andrew Pavlin<br><br><div><div id="SkyDrivePlaceholder"></div><hr id="stopSpelling">Date: Sun, 18 Nov 2012 13:59:03 -0500<br>From: wa8lmf2@aol.com<br>To: aprssig@tapr.org<br>Subject: Re: [aprssig] Can YAAC or APRSIS32 do a CAVE.JPG map?<br><br>
<div class="ecxmoz-cite-prefix">On 11/18/2012 11:29 AM, Robert Bruninga
wrote:<br>
</div>
<blockquote cite="mid:CALdCfNKojRHZBLk4SYn+qqh+B+R-=WB4ODirT2WVVi=pz=iBpQ@mail.gmail.com">
<pre>Can YAAC or APSIS32 accomodate JPG maps easily?
I need to figure out how to get the Mammoth Cave map into an APRS client.
The map is geographically correct, but I need to register the LAT/LONG
from two corner points and then be able to load it and be able to ZOOM
it during operation.
</pre>
</blockquote>
<br>
1) Once again, .JPG is *<b>NO</b><b>T</b>* the proper format
for B & W text and non-continuous-tone images like maps, graphs
& charts, mechanical drawings, schematics, etc. <br>
<br>
JPG should <b>only</b> be used for continuous-tone real-life
photos. The .JPG compression algorithms look for gradual gradients
between adjacent pixels. When confronted with abrupt jumps from
one solid color to another (or from black to white) you only get a
hideous fuzzy"squirmy" blur at the transition from one solid color
to another, if any worthwhile amount of compression is being
applied. <br>
<br>
The proper lossless formats for images with abrupt transitions
between solid colors are .GIF, .BMP .PNG or .TIF. For images with a
limited number of solid colors (256, 128, 16 or fewer colors) like
maps, almost always .GIF will yield the smallest file. <br>
<br>
<br>
2) No bitmap format like .JPG, .BMP, .GIF, etc that is a fixed
grid of pixels is going to yield any more detail by zooming in. You
just get big chunky blocks as the individual pixels are enlarged.
For usable zooming, you have to use vector formats such as .WMF,
.SVG, .DXF, .DWG (AutoCad), .AI (Adobe Illustrator), .SHP
(ArcView), etc. <br>
<br>
<br>
3) Uiview has a very straight-forward calibration routine that
accepts any bitmap in .JPG, .BMP, .PNG, or .GIF format. Just
drag-and-drop any such image from the Windows File Explorer into the
open UIview main window. A calibration dialog automatically pops
up that allows you to either specify the lat/long of the upper-left
and lower-right corners --OR-- you can click on any two points with
known lat/longs (typically things like highway junctions,
recognizable structures in aerial photos, etc) in the image and
specify their lat/longs instead. <br>
<br>
UIview can accommodate bitmap images far larger than it's display
window. Instead of downsizing the image to fit with the resulting
loss of detail, the UIview window becomes a scrollable viewport
showing a part of the image at full native resolution instead. <br>
<br>
With the Precision Mapping 9.0 server add-on and Precision Mapping
9.0 installed, you can either slip a calibrated bitmap underneath
the transparent vector layers displayed in Uiview. Or actually use
it to display your own fully-zoomable home-made vector images in
ArcView .SHP, or MapInfo .MIF format. <br>
<br>
If the orignal bitmap image of the map in question is reasonably
clean, the trace utilities included with Corel Draw or Adobe
Illustrator can "follow the lines" between colors and create a
vector version of the image. <br>
<br>
Some details on using the vector capabilities of Precision Mapping
are here on my website:<br>
<a class="ecxmoz-txt-link-rfc2396E" href="http://wa8lmf.net/aprs/PMapEuroMapSamples/index.htm" target="_blank"><http://wa8lmf.net/aprs/PMapEuroMapSamples/index.htm></a><br>
<br>
<br>
<hr size="2" width="100%"><br>
--<br>
<br>
Stephen H. Smith wa8lmf (at) aol.com <br>
Skype: WA8LMF<br>
Home Page: <a class="ecxmoz-txt-link-freetext" href="http://wa8lmf.net" target="_blank">http://wa8lmf.net</a><br>
<br>
<br>
Acer 756 Netbook: Versatile Inexpensive Platform for Ham Apps<br>
<a class="ecxmoz-txt-link-freetext" href="http://wa8lmf.net/netbook" target="_blank">http://wa8lmf.net/netbook</a><br>
<br>
High Quality Calibrated Static Maps for Any APRS App <br>
<a class="ecxmoz-txt-link-freetext" href="http://wa8lmf.net/aprs/PM9_StaticMap_Export.htm" target="_blank">http://wa8lmf.net/aprs/PM9_StaticMap_Export.htm</a><br>
<br>
Vista & Win7 Install Issues for UI-View and Precision Mapping<br>
<a class="ecxmoz-txt-link-freetext" href="http://wa8lmf.net/aprs/UIview_Notes.htm#VistaWin7" target="_blank">http://wa8lmf.net/aprs/UIview_Notes.htm#VistaWin7</a><br>
<br>
"APRS 101" Explanation of APRS Path Selection & Digipeating <br>
<a class="ecxmoz-txt-link-freetext" href="http://wa8lmf.net/DigiPaths" target="_blank">http://wa8lmf.net/DigiPaths</a> <br>
<br>
<br>
<br>
<br>_______________________________________________
aprssig mailing list
aprssig@tapr.org
https://www.tapr.org/cgi-bin/mailman/listinfo/aprssig</div> </div></body>
</html>