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<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=222022407-31072008>Hi,</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=222022407-31072008></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><SPAN class=222022407-31072008><FONT face=Arial
color=#0000ff size=2>What are the dimensions of the image you have captured
in real world utits? Your original aerial images have half a metre
pixel size. It mean that at 300 dpi one original image
pixel corresponds with one pixel at paper if square inch on your
printout is presenting exactly 150 by 150 meters in nature. That is
the maximum quality you can achieve. If square inch on
paper equals to 75 by 75 meters the maximum quolity is achieved
already at 150 dpi. Multiplicating original image pixels for printing
cannot improve the quality. But if you have zoomed out so far that
creating output image means downsampling the original imagery you should see the
differense. So, if your 2150x1111 low resolution image is covering a
considerably larger area than 1075x555 meters in real world it should look
better when downloaded at 300 dpi with 4300x2222
pixels. </FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=222022407-31072008><FONT face=Arial
color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=222022407-31072008><FONT face=Arial
color=#0000ff size=2>-Jukka Rahkonen-</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=222022407-31072008><FONT face=Arial
color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=222022407-31072008></SPAN><SPAN
class=222022407-31072008> </SPAN></DIV>
<DIV dir=ltr align=left>
<HR tabIndex=-1>
</DIV>
<DIV dir=ltr align=left><FONT face=Tahoma size=2><B>Lähettäjä:</B>
mapserver-users-bounces@lists.osgeo.org
[mailto:mapserver-users-bounces@lists.osgeo.org] <B>Puolesta
</B>Dejan.Gambin@pula.hr<BR><B>Lähetetty:</B> 31. heinäkuuta 2008
9:32<BR><B>Vastaanottaja:</B> mapserver-users@lists.osgeo.org<BR><B>Aihe:</B>
Re: [mapserver-users] Output image resolution - explanation
needed<BR></FONT><BR></DIV>
<BLOCKQUOTE
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px solid; MARGIN-RIGHT: 0px">
<DIV></DIV><BR><FONT face=sans-serif size=2>Thanks Steve</FONT> <BR><BR><FONT
face=sans-serif size=2>I still (unfortunatelly) don't understand why I am
getting the "same quality" image on the paper with the first and second print
(the second image has twice more pixels). Is it because of the input image
itself? To be specific - the raster input is aerial image that gdalinfor
reports as:</FONT> <BR><BR><FONT face=sans-serif size=2>Driver:
GTiff/GeoTIFF</FONT> <BR><FONT face=sans-serif size=2>Files:
5C14-05-DOF.tif</FONT> <BR><FONT face=sans-serif size=2>Size is 4500,
6000</FONT> <BR><FONT face=sans-serif size=2>Coordinate System is `'</FONT>
<BR><FONT face=sans-serif size=2>Origin =
(5419000.154658853100000,4964998.794652804700000)</FONT> <BR><FONT
face=sans-serif size=2>Pixel Size =
(0.499829146050620,-0.499829146050620)</FONT> <BR><FONT face=sans-serif
size=2>Corner Coordinates:</FONT> <BR><FONT face=sans-serif size=2>Upper Left
( 5419000.155, 4964998.795)</FONT> <BR><FONT face=sans-serif
size=2>Lower Left ( 5419000.155, 4961999.820)</FONT> <BR><FONT
face=sans-serif size=2>Upper Right ( 5421249.386, 4964998.795)</FONT>
<BR><FONT face=sans-serif size=2>Lower Right ( 5421249.386,
4961999.820)</FONT> <BR><FONT face=sans-serif size=2>Center
( 5420124.770, 4963499.307)</FONT> <BR><FONT face=sans-serif size=2>Band
1 Block=256x256 Type=Byte, ColorInterp=Red</FONT> <BR><FONT face=sans-serif
size=2> Overviews: 2250x3000, 1125x1500, 563x750, 282x375</FONT>
<BR><FONT face=sans-serif size=2>Band 2 Block=256x256 Type=Byte,
ColorInterp=Green</FONT> <BR><FONT face=sans-serif size=2> Overviews:
2250x3000, 1125x1500, 563x750, 282x375</FONT> <BR><FONT face=sans-serif
size=2>Band 3 Block=256x256 Type=Byte, ColorInterp=Blue</FONT> <BR><FONT
face=sans-serif size=2> Overviews: 2250x3000, 1125x1500, 563x750,
282x375</FONT> <BR><BR><FONT face=sans-serif size=2>regards, dejan</FONT>
<BR><BR><TT><FONT size=2>"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 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
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 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>>
<BR></BLOCKQUOTE></FONT></TT></BODY></HTML>