We have discovered
an interesting default behavior using WMS in ESRI ArcGIS software. This is
not really a 'bug', just the way ArcMap handles WMS
requests.
By default, ArcMap
will assign a 'background' color to WMS, which by default is white (255 255 255
pixel value). There are a few of the new WMS (Baxter 2004, SPOT) that
have clouds which have some pixels showing pure white (255 255 255). Since
by default ArcMap considers this the default background color, it renders all
pixels that are pure white as transparent. Thus you will see 'holes' in
the clouds and can view whatever layers are underneath them, which makes for
curious mapping!
A simple solution is
to go into the layer properties, Advanced tab, and turn off the checkbox that
makes the background value transparent.
MEGIS will go
through and make this change on the LYR files we host on the WMS web page within
the next few days.
This behavior is not
apparent in other WMS clients tested including Google Earth, QGIS, and
Gaia.
**********
Michael
Smith
State GIS Manager
Maine Office of GIS
State House Station 174
264 Civic Center
Drive
Augusta ME 04333-0174
(207) 215-5530
Member, Maine GeoLibrary
Board
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