[Geotools-devel] Some headache with a old (14+ years) decision in rendering subsystem

[Andrea A. <and...@ge...>]

Hi,
I was looking into this geoserver ticket:

https://osgeo-org.atlassian.net/browse/GEOS-4923

The reported correctly traces it to the logic used to decide is a rule is
in scale range, and indeed the
specification says:

"The MinScaleDenominator and MaxScaleDenominator elements, as their names
suggest, are simply the minimum and maximum ranges of scale (denominators)
of maps
for which a rule should apply. The minimum scale is inclusive and the
maximum scale is
exclusive"

I checked if StreamingRenderer does the same, and indeed, it does. Went
back with svn to
the initial commit of "LiteRenderer" by yours truly in 2003 (I cannot find
an older renderer package
in there, we are talking about the original 2.0.x branch!) and the logic
with tolerance was already there.

Now... I can understand the tolerance, clients and servers are almost never
computing
the value with the exact same precision (think float vs double, or just
slight variations in the expression
setup), but indeed hitting a threshold scale exactly makes both rules to
trigger...

Soo... possible approaches:

   - Just remove the tolerances altoghether. Simple,clean, we'll get some
   users complaining that their client is stating a scale at which rules
   should trigger, and they don't
   - Remove it only from max scale denominator check? It's still possible
   to make the two rules trigger but getting at a value between target and
   "scale - tolerance"
   - Add some sophisticated logic that favours the min rules in case we
   have both? (but not fully sure how to write it)

More ideas? Suggestions? Any takers?

Cheers
Andrea

==
GeoServer Professional Services from the experts! Visit http://goo.gl/it488V
for more information.
==

Ing. Andrea Aime
@geowolf
Technical Lead

GeoSolutions S.A.S.
Via di Montramito 3/A
55054  Massarosa (LU)
phone: +39 0584 962313
fax: +39 0584 1660272
mob: +39  339 8844549

http://www.geo-solutions.it
http://twitter.com/geosolutions_it

AVVERTENZE AI SENSI DEL D.Lgs. 196/2003

Le informazioni contenute in questo messaggio di posta elettronica e/o
nel/i file/s allegato/i sono da considerarsi strettamente riservate. Il
loro utilizzo è consentito esclusivamente al destinatario del messaggio,
per le finalità indicate nel messaggio stesso. Qualora riceviate questo
messaggio senza esserne il destinatario, Vi preghiamo cortesemente di
darcene notizia via e-mail e di procedere alla distruzione del messaggio
stesso, cancellandolo dal Vostro sistema. Conservare il messaggio stesso,
divulgarlo anche in parte, distribuirlo ad altri soggetti, copiarlo, od
utilizzarlo per finalità diverse, costituisce comportamento contrario ai
principi dettati dal D.Lgs. 196/2003.

The information in this message and/or attachments, is intended solely for
the attention and use of the named addressee(s) and may be confidential or
proprietary in nature or covered by the provisions of privacy act
(Legislative Decree June, 30 2003, no.196 - Italy's New Data Protection
Code).Any use not in accord with its purpose, any disclosure, reproduction,
copying, distribution, or either dissemination, either whole or partial, is
strictly forbidden except previous formal approval of the named
addressee(s). If you are not the intended recipient, please contact
immediately the sender by telephone, fax or e-mail and delete the
information in this message that has been received in error. The sender
does not give any warranty or accept liability as the content, accuracy or
completeness of sent messages and accepts no responsibility  for changes
made after they were sent or for other risks which arise as a result of
e-mail transmission, viruses, etc.