[OSGeo-Discuss] How to assess rendering quality?

[Ed McNierney]

Gilles -

Just keep in mind that subjective metrics are, after all, subjective, and some of your metrics are mutually exclusive.  "Smoothness of lines" is normally accomplished by antialiasing those lines, making the edges intermediate colors and a little "soft".  This is a good thing, but is incompatible with "sharpness of details", which is best accomplished without antialiasing but with more jagged artifacts on curves and diagonal lines.

	- Ed

Ed McNierney
Chief Mapmaker
Demand Media / TopoZone.com
73 Princeton Street, Suite 305
North Chelmsford, MA  01863
Phone: 978-251-4242, Fax: 978-251-1396
ed at topozone.com




-----Original Message-----
From: discuss-bounces at lists.osgeo.org [mailto:discuss-bounces at lists.osgeo.org] On Behalf Of Gilles Bassière
Sent: Wednesday, October 10, 2007 8:38 AM
To: OSGeo Discussions
Subject: Re: [OSGeo-Discuss] How to assess rendering quality?

Hi Michael,

I'm more concerned with subjective metrics, I actually plan to survey 
some users. The questionnaire will include some map samples and gather 
user preference for each criteria. My problem is to identify what 
questions/criteria should I ask to a user.

Gilles


Michael P. Gerlek wrote:
> Gilles-
>
> Is your idea to measure the quality by having a human look at outputs (subjective metrics) or automatically via some analysis routine (objective metrics)?
>
> -mpg
>
>  
>
>   
>> -----Original Message-----
>> From: discuss-bounces at lists.osgeo.org 
>> [mailto:discuss-bounces at lists.osgeo.org] On Behalf Of Gilles Bassière
>> Sent: Wednesday, October 10, 2007 3:01 AM
>> To: discuss at lists.osgeo.org
>> Subject: [OSGeo-Discuss] How to assess rendering quality?
>>
>> Hi list,
>>
>> I'm doing a comparative study of OpenSource cartographic servers 
>> (Mapserver, Geoserver and Mapnik). Beside raw performance and 
>> features, 
>> I'd like to assess the rendering quality, say how pretty 
>> produced maps 
>> are. Precisely, I'm interested in the quality of the drawing work, my 
>> point is not about symbology, nor styling of maps.
>>
>> I have some problems to find a set of objective criteria I could 
>> benchmark my servers against. So far, I have already identified the 
>> following:
>> - sharpness of details
>> - smoothness of lines
>> - uniformity of colors
>>
>> I'm open to any comments. Do you think these criteria are consistent 
>> regarding the purpose of my study? Does anyone have other criteria to 
>> suggest?
>>
>> Regards
>>
>> -- 
>> Gilles Bassiere
>> MAKINA CORPUS
>> 30 rue des Jeuneurs
>> FR-75011 PARIS
>> http://www.makina-corpus.com
>>
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>>
>>     
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>   


-- 
Gilles Bassiere
MAKINA CORPUS
30 rue des Jeuneurs
FR-75011 PARIS
http://www.makina-corpus.com

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