[mapserver-users] WMS: raster's x and y pixel dimension

Rahkonen Jukka Jukka.Rahkonen at mmmtike.fi
Tue Dec 1 13:33:42 PST 2009


Hi,

I would say that the main difference is that WMS is meant for showing a map on a computer screen, while WCS is made for letting users to download data so they can utilise it locally or process further.  Real life is not so black and white.  I promise you will find lots of good reading about WMS and WCS easily.  Do not forget to read a little bit about WFS as well, service for downloading vector data.

-Jukka Rahkonen-


fla83tn wrote:

Lähetetty: ti 1.12.2009 17:31
Vastaanottaja: Rahkonen Jukka; mapserver-users at lists.osgeo.org
Aihe: Re: Re: [mapserver-users] WMS: raster's x and y pixel dimension
 
Thank you Jukka for the quick reply. Now I'm able to correctly generate z-
dimension from DEM layer.
However, since I'm new to GIS, I'm not able to 
understand the differences between WCS and WMS..could 
you briefly summarize 
the goal of the two approach?
And, as last question , should I set the resX and 
resY parameters from client or could I embed them directly into the map file?


Best regards, 
Flavio

>Hi,
>
>Width, height and BBOX are all compulsory 
parameters in WMS GetMap
>request and Mapserver is sending an image according 
to the request.  If
>you want to be able to control the pixel size easily, 
without making WMS
>client to balance the BBOX and image size in pixels, 
consider using WCS.
>One way to make a WCS request is 
>
>http://server.fi/cgi-
bin/mapserver_wcs?SERVICE=WCS&VERSION=1.0.0&REQUEST

>=GetCoverage&COVERAGE=DEM&FORMAT=image/tiff&CRS=EPSG:3067&ResX=1.0&ResY=
>1.
0&BBOX=533652,6973434,534658,6974219
>
>You can see parameters ResX and ResY 
which are used for controlling the
>pixel size.
>
>-Jukka Rahkonen-
>
>fla83tn 
wrote:
>
>> 
>> Hi to all,
>> I've a problem with the loading of  a raster 
image via WMS (1.3.0).
>> 
>> To load the layers of my project I use gvSIG. If 
I load my 
>> digital elevation model (DEM) directly from filesystem (which 
>> 
is a HFA/Erdas Image file - .img), 
>> 
>> x and y pixel dimension are fixed to 
2.5 and -2.5 meters 
>> respectively, and fixed are also the width and height 
attributes.
>> If I load the layer from
>> Mapserver's WMS instead, x and y 
pixel dimension change as I 
>> zoom in or out (i.
>> e. changing the width
>> 
and height parameters of the getMap request). 
>> Is there
>> the possibility 
to tell the wms client that x and y pixel 
>> dimension are constant and should 
never be calculated?
>> 
>> Here's my layer definition and the
>> tiff 
outputformat definition:
>> 
>> OUTPUTFORMAT
>>   NAME GTiff
>>   DRIVER 
"GDAL/GTiff"
>> 
>>   MIMETYPE "image/tiff"
>>   IMAGEMODE FLOAT32
>>   
EXTENSION "tif"
>> END
>> 
>> LAYER
>>   NAME
>> "my_dem"
>>   EXTENT 669913.75 
5143998.75 678313.75 5150701.25
>> 	
>>   METADATA
>>     
>> "wms_title"    
"my_dem"   ##required
>>     "wms_extent" "669913.75 5143998.75
>> 678313.75 
5150701.25"
>>     "gml_include_items" "all"
>>   END
>>   TYPE RASTER
>>   
>> 
STATUS ON
>>   PROJECTION
>>          "init=epsg:25832"
>>   END  
>> 
>>   
DATA "my_dem.tiff"
>> 
>>   PROCESSING "NODATA=-9999"
>>   PROCESSING 
"SCALE=227.23,1741.15"
>>   PROCESSING
>> "SCALE_BUCKETS=2000"
>>   PROCESSING 
"BANDS=1"
>>   
>>   DEBUG on
>>   DUMP 	true
>>   
>> TEMPLATE "void" # enable 
queryable attribute on the layer END
>> 
>> Any help is
>> appreciated,
>> 
Flavio
>> _______________________________________________
>> mapserver-users 
mailing list
>> mapserver-users at lists.osgeo.org
>> http://lists.osgeo.
org/mailman/listinfo/mapserver-users
>> 
>






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