<br><font size=2 face="sans-serif">Thanks, you helped me a lot</font>
<br>
<br><font size=2 face="sans-serif">In my example, I have printed an area
of aproximately 1km wide on an A4 Landscape that is 29,7cm wide, so 1inch
is about 85.5m. So that should be the reason? :-)</font>
<br>
<br><font size=2 face="sans-serif">regards, dejan</font>
<br>
<br><tt><font size=2>"Rahkonen Jukka" <Jukka.Rahkonen@mmmtike.fi>
wrote on 31.07.2008 11:00:15:<br>
<br>
> Hi,</font></tt>
<br><tt><font size=2>> </font></tt>
<br><tt><font size=2>> What are the dimensions of the image you have
captured in real world<br>
> utits? Your original aerial images have half a metre pixel size.
<br>
> It mean that at 300 dpi one original image pixel corresponds with
<br>
> one pixel at paper if square inch on your printout is presenting <br>
> exactly 150 by 150 meters in nature. That is the maximum quality
<br>
> you can achieve. If square inch on paper equals to 75 by 75
meters <br>
> the maximum quolity is achieved already at 150 dpi. Multiplicating
<br>
> original image pixels for printing cannot improve the quality. But
<br>
> if you have zoomed out so far that creating output image means <br>
> downsampling the original imagery you should see the differense. <br>
> So, if your 2150x1111 low resolution image is covering a <br>
> considerably larger area than 1075x555 meters in real world it <br>
> should look better when downloaded at 300 dpi with 4300x2222 pixels.
</font></tt>
<br><tt><font size=2>> </font></tt>
<br><tt><font size=2>> -Jukka Rahkonen-</font></tt>
<br><tt><font size=2>> </font></tt>
<br><tt><font size=2>> </font></tt>
<br><tt><font size=2>> <br>
> Lähettäjä: mapserver-users-bounces@lists.osgeo.org [mailto:<br>
> mapserver-users-bounces@lists.osgeo.org] Puolesta Dejan.Gambin@pula.hr<br>
> Lähetetty: 31. heinäkuuta 2008 9:32<br>
> Vastaanottaja: mapserver-users@lists.osgeo.org<br>
> Aihe: Re: [mapserver-users] Output image resolution - explanation
needed<br>
</font></tt>
<br><tt><font size=2>> <br>
> Thanks Steve <br>
> <br>
> I still (unfortunatelly) don't understand why I am getting the "same<br>
> quality" image on the paper with the first and second print (the
<br>
> second image has twice more pixels). Is it because of the input <br>
> image itself? To be specific - the raster input is aerial image that<br>
> gdalinfor reports as: <br>
> <br>
> Driver: GTiff/GeoTIFF <br>
> Files: 5C14-05-DOF.tif <br>
> Size is 4500, 6000 <br>
> Coordinate System is `' <br>
> Origin = (5419000.154658853100000,4964998.794652804700000) <br>
> Pixel Size = (0.499829146050620,-0.499829146050620) <br>
> Corner Coordinates: <br>
> Upper Left ( 5419000.155, 4964998.795) <br>
> Lower Left ( 5419000.155, 4961999.820) <br>
> Upper Right ( 5421249.386, 4964998.795) <br>
> Lower Right ( 5421249.386, 4961999.820) <br>
> Center ( 5420124.770, 4963499.307) <br>
> Band 1 Block=256x256 Type=Byte, ColorInterp=Red <br>
> Overviews: 2250x3000, 1125x1500, 563x750, 282x375 <br>
> Band 2 Block=256x256 Type=Byte, ColorInterp=Green <br>
> Overviews: 2250x3000, 1125x1500, 563x750, 282x375 <br>
> Band 3 Block=256x256 Type=Byte, ColorInterp=Blue <br>
> Overviews: 2250x3000, 1125x1500, 563x750, 282x375 <br>
> <br>
> regards, dejan <br>
> <br>
> "Steve Lime" <Steve.Lime@dnr.state.mn.us> wrote on
30.07.2008 21:13:55:<br>
> <br>
> > Resolution in MapServer-speak is referring to the resolution
of the <br>
> > output device a map<br>
> > will be displayed on. The value is used for scale computations
and <br>
> > nothing else. It does not<br>
> > affect the size (in pixels) of MapServer. Scale values do impact
the<br>
> > size at which features<br>
> > and text are rendered IF scaling (via SYMBOLSCALE) is turned
on. <br>
> > Higher quality output is<br>
> > usually a matter of having more pixels to print, however you
usually<br>
> > want larger features<br>
> > too which is where the resolution parameter combined with scaling
can help.<br>
> > <br>
> > Steve<br>
> > <br>
> > >>> On 7/30/2008 at 2:21 AM, in message<br>
> > <OF8A10F31F.0E3F1C94-ONC1257496.0026AB23-C1257496.00286464@pula.hr>,<br>
> > <Dejan.Gambin@pula.hr> wrote:<br>
> > > Hi,<br>
> > > <br>
> > > I am trying to download a high resolution image and print
it on <br>
> a paper. I <br>
> > > am using p.mapper and its download function that enables
downloading the <br>
> > > map image on different resolutions. <br>
> > > <br>
> > > I have turned on my raster layer (ortophoto image). I have
<br>
> zoomed in to an <br>
> > > area of interest. I have downloaded the map twice - with
a resolution of <br>
> > > 150 and 300. The image is shown i a new page/tab (firefox).
I right click <br>
> > > on the image and save it as a png (also tried with a jpeg)
file.Now, the <br>
> > > first file is 2150x1111 pixels, 120 dpi vertical and horizontal
<br>
> resolution <br>
> > > (right click on a file, properties, summary, what does it
mean?), the <br>
> > > second file is 4300x2222 pixels, 120 dpi vertical and horizontal
<br>
> > > resolution. Seems ok. The second image is "doubled"
in pixel size.<br>
> > > <br>
> > > Now, when I try to print this image on A4 paper, using 300dpi,
the images <br>
> > > are the same, there is no "better quality" in
second image.<br>
> > > <br>
> > > I have just finshed reading the Mapserver thread on "Change
image <br>
> > > resolution in mapfile". Several limitations are mentioned
there - max. <br>
> > > image size supported by Mapserver, "resolution"
value/tag embedded in <br>
> > > output format, etc. Can it be related to my problem? Or
is it maybe that <br>
> > > software I am using to print this image doesn't "use"
this extra pixels? <br>
> > > Or I am just missing some basic stuff I need to know :-(<br>
> > > <br>
> > > <br>
> > > thanks very much on any explanation<br>
> > > <br>
> > > regards, dejan<br>
> > </font></tt>