[mapserver-commits] r13243 - branches/branch-6-0/docs/en
trunk/docs/en
svn at osgeo.org
svn at osgeo.org
Tue Mar 13 18:29:04 EDT 2012
Author: havatv
Date: 2012-03-13 15:29:04 -0700 (Tue, 13 Mar 2012)
New Revision: 13243
Modified:
branches/branch-6-0/docs/en/faq.txt
trunk/docs/en/faq.txt
Log:
Some updates to the FAQ (AGG - GD) (#4246).
Modified: branches/branch-6-0/docs/en/faq.txt
===================================================================
--- branches/branch-6-0/docs/en/faq.txt 2012-03-13 21:22:59 UTC (rev 13242)
+++ branches/branch-6-0/docs/en/faq.txt 2012-03-13 22:29:04 UTC (rev 13243)
@@ -206,11 +206,24 @@
How do I set line width in my maps?
-------------------------------------------------------------------------------
-You must set the symbol for the LAYER to be 'circle' and then you can set the
-symbol SIZE to be the width you want. A 'circle' symbol can be defined as
+In the current Mapserver version, line width is set using
+the STYLE parameter WIDTH. For a LINE layer, lines can be
+made red and 3 pixels wide by using the following style in
+a CLASS.
.. code-block:: mapfile
+ STYLE
+ COLOR 255 0 0
+ WIDTH 3
+ END
+
+In earlier versions of Mapserver, you could set the symbol for the
+LAYER to 'circle' and then you can set the symbol SIZE to be the
+width you want. A 'circle' symbol can be defined as
+
+.. code-block:: mapfile
+
SYMBOL
NAME 'circle'
TYPE ELLIPSE
@@ -221,18 +234,25 @@
Why do my JPEG input images look crappy via MapServer?
-------------------------------------------------------------------------------
-The default output format for MapServer is 8bit pseudo-colored PNG or GIF.
-Inherently there will be some color degredation in converting a 24bit image
-(16 million colors) image into 8bit (256 colors).
+You must be using an old version of Mapserver (where GD was the
+default library for rendering).
-But in order to ensure fast rendering MapServer uses quite a simple method to
-do the transformation, converting pixels to the nearest color in a 175 color
-colorcube. This will usually result in blotchy color in a fairly smoothly
-varying image.
+Newer versions of Mapserver use AGG for rendering, and the default
+output formats is 24 bit colour, so there should not be a problem.
-Solutions include:
+The default output format for MapServer with GD was 8bit
+pseudo-colored PNG or GIF. Inherently there will be some color
+degradation in converting a 24bit image (16 million colors) image into
+8bit (256 colors).
-- Select 24bit output. This might be as easy as "IMAGETYPE JPEG" in your MAP
+With GD output, MapServer used quite a simple method to do the
+transformation, converting pixels to the nearest color in a 175 color
+colorcube. This would usually result in blotchy color in a fairly
+smoothly varying image.
+
+For GD, solutions used to be:
+
+- Select 24bit output. This might be as easy as "IMAGETYPE JPEG" in your MAP
section.
- Enable dithering (PROCESSING "DITHER=YES") to produce a better color
appearance.
@@ -244,7 +264,7 @@
Which image format should I use?
-------------------------------------------------------------------------------
-Although MapScript can generate the map in any desired image format it
+Although MapScript can generate the map in any desired image format it is
sufficient to only consider the three most prevalent ones: JPEG, PNG, and GIF.
JPEG is an image format that uses a lossy compression algorithm to reduce an
@@ -279,7 +299,7 @@
Although GIF shows a quantitative as well as qualitative advantage over PNG
when generating maps that contain full coloured remote sensing imagery, PNG is
the clear quantitative winner in terms of generated file sizes for maps with
-or without additional monochrome imagery and should therefore been the
+or without additional monochrome imagery and should therefore be the
preferred image format. If the mapping application however can also display
fullcolour aerial or satellite imagery, the output file format can be changed
dynamically to either GIF or even PNG24 to achieve the highest possible image
@@ -310,6 +330,10 @@
When I render my symbols to an 8bit output (PNG, GIF) they look fine, but in
24bit jpeg output they look very blocky and gross.
+You must be using an old version of Mapserver. This should not be
+problem with newer versions. The following explains the old (GD)
+behaviour.
+
In order to render some classes of symbols properly in 24bit output, such as
symbols from true type fonts, it is necessary to force rendering to occur in
RGBA. This can be accomplished by including the "TRANSPARENCY ALPHA" line in
@@ -349,8 +373,12 @@
SIZE 8
BUFFER 1
COLOR 0 0 0
- BACKGROUNDCOLOR 255 255 255
+ # BACKGROUNDCOLOR 255 255 255 # old way
FORCE TRUE
+ STYLE # new in mapserver 6
+ GEOMTRANSFORM 'labelpoly'
+ COLOR 255 255 255
+ END # STYLE
END
END
UNITS PIXELS #sets the units for the feature object
@@ -381,22 +409,25 @@
STYLE # solid fill
COLOR 255 0 0
END
- STYLE # thick outline (could use a circle symbol with size too)
+ STYLE # thick outline
OUTLINECOLOR 0 0 0
WIDTH 3
- ANTIALIAS TRUE
END
How can I create simple antialiased line features?
-------------------------------------------------------------------------------
-The easiest way to produce antialiased lines is to:
+With AGG (used in recent Mapserver version), antialiased lines is the
+default, and can't be turned off.
+With GD, the easiest way to produce antialiased lines is to:
+
- use a 24-bit output image type (IMAGEMODE RGB (or RGBA))
- set TRANSPARENCY ALPHA in the layer using antialiased lines
- set ANTIALIAS TRUE in the STYLE element of the CLASS with antialiased lines
-The following mapfile snippets enable antialiased county borders:
+The following mapfile snippets enable antialiased county borders for
+GD:
.. code-block:: mapfile
@@ -448,7 +479,7 @@
Which OGC Specifications does MapServer support?
-------------------------------------------------------------------------------
-See: :ref:`OGCSUPPORT`
+See: :ref:`ogc_support`.
Why does my requested WMS layer not align correctly?
-------------------------------------------------------------------------------
Modified: trunk/docs/en/faq.txt
===================================================================
--- trunk/docs/en/faq.txt 2012-03-13 21:22:59 UTC (rev 13242)
+++ trunk/docs/en/faq.txt 2012-03-13 22:29:04 UTC (rev 13243)
@@ -206,11 +206,24 @@
How do I set line width in my maps?
-------------------------------------------------------------------------------
-You must set the symbol for the LAYER to be 'circle' and then you can set the
-symbol SIZE to be the width you want. A 'circle' symbol can be defined as
+In the current Mapserver version, line width is set using
+the STYLE parameter WIDTH. For a LINE layer, lines can be
+made red and 3 pixels wide by using the following style in
+a CLASS.
.. code-block:: mapfile
+ STYLE
+ COLOR 255 0 0
+ WIDTH 3
+ END
+
+In earlier versions of Mapserver, you could set the symbol for the
+LAYER to 'circle' and then you can set the symbol SIZE to be the
+width you want. A 'circle' symbol can be defined as
+
+.. code-block:: mapfile
+
SYMBOL
NAME 'circle'
TYPE ELLIPSE
@@ -221,18 +234,25 @@
Why do my JPEG input images look crappy via MapServer?
-------------------------------------------------------------------------------
-The default output format for MapServer is 8bit pseudo-colored PNG or GIF.
-Inherently there will be some color degredation in converting a 24bit image
-(16 million colors) image into 8bit (256 colors).
+You must be using an old version of Mapserver (where GD was the
+default library for rendering).
-But in order to ensure fast rendering MapServer uses quite a simple method to
-do the transformation, converting pixels to the nearest color in a 175 color
-colorcube. This will usually result in blotchy color in a fairly smoothly
-varying image.
+Newer versions of Mapserver use AGG for rendering, and the default
+output formats is 24 bit colour, so there should not be a problem.
-Solutions include:
+The default output format for MapServer with GD was 8bit
+pseudo-colored PNG or GIF. Inherently there will be some color
+degradation in converting a 24bit image (16 million colors) image into
+8bit (256 colors).
-- Select 24bit output. This might be as easy as "IMAGETYPE JPEG" in your MAP
+With GD output, MapServer used quite a simple method to do the
+transformation, converting pixels to the nearest color in a 175 color
+colorcube. This would usually result in blotchy color in a fairly
+smoothly varying image.
+
+For GD, solutions used to be:
+
+- Select 24bit output. This might be as easy as "IMAGETYPE JPEG" in your MAP
section.
- Enable dithering (PROCESSING "DITHER=YES") to produce a better color
appearance.
@@ -244,7 +264,7 @@
Which image format should I use?
-------------------------------------------------------------------------------
-Although MapScript can generate the map in any desired image format it
+Although MapScript can generate the map in any desired image format it is
sufficient to only consider the three most prevalent ones: JPEG, PNG, and GIF.
JPEG is an image format that uses a lossy compression algorithm to reduce an
@@ -279,7 +299,7 @@
Although GIF shows a quantitative as well as qualitative advantage over PNG
when generating maps that contain full coloured remote sensing imagery, PNG is
the clear quantitative winner in terms of generated file sizes for maps with
-or without additional monochrome imagery and should therefore been the
+or without additional monochrome imagery and should therefore be the
preferred image format. If the mapping application however can also display
fullcolour aerial or satellite imagery, the output file format can be changed
dynamically to either GIF or even PNG24 to achieve the highest possible image
@@ -310,6 +330,10 @@
When I render my symbols to an 8bit output (PNG, GIF) they look fine, but in
24bit jpeg output they look very blocky and gross.
+You must be using an old version of Mapserver. This should not be
+problem with newer versions. The following explains the old (GD)
+behaviour.
+
In order to render some classes of symbols properly in 24bit output, such as
symbols from true type fonts, it is necessary to force rendering to occur in
RGBA. This can be accomplished by including the "TRANSPARENCY ALPHA" line in
@@ -349,8 +373,12 @@
SIZE 8
BUFFER 1
COLOR 0 0 0
- BACKGROUNDCOLOR 255 255 255
+ # BACKGROUNDCOLOR 255 255 255 # old way
FORCE TRUE
+ STYLE # new in mapserver 6
+ GEOMTRANSFORM 'labelpoly'
+ COLOR 255 255 255
+ END # STYLE
END
END
UNITS PIXELS #sets the units for the feature object
@@ -381,22 +409,25 @@
STYLE # solid fill
COLOR 255 0 0
END
- STYLE # thick outline (could use a circle symbol with size too)
+ STYLE # thick outline
OUTLINECOLOR 0 0 0
WIDTH 3
- ANTIALIAS TRUE
END
How can I create simple antialiased line features?
-------------------------------------------------------------------------------
-The easiest way to produce antialiased lines is to:
+With AGG (used in recent Mapserver version), antialiased lines is the
+default, and can't be turned off.
+With GD, the easiest way to produce antialiased lines is to:
+
- use a 24-bit output image type (IMAGEMODE RGB (or RGBA))
- set TRANSPARENCY ALPHA in the layer using antialiased lines
- set ANTIALIAS TRUE in the STYLE element of the CLASS with antialiased lines
-The following mapfile snippets enable antialiased county borders:
+The following mapfile snippets enable antialiased county borders for
+GD:
.. code-block:: mapfile
@@ -448,7 +479,7 @@
Which OGC Specifications does MapServer support?
-------------------------------------------------------------------------------
-See: :ref:`OGCSUPPORT`
+See: :ref:`ogc_support`.
Why does my requested WMS layer not align correctly?
-------------------------------------------------------------------------------
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