Matthias Basler wrote:
Zitat von Jody:
2) Styles for elevation:
I want to shade a series of polygons different colours according to the
"ELEV_MIN" field and am puzzled by the "number of classes" field. I
obviously want the number of classes to be the number of unique values
in the field. I also want a nice gradient from green to yellow to brown
to white---a classic elevation setup. I found a style that's close to
what I wanted but it's only got nine classes. Am I doing something wrong
or is this simply due to the initial state of the styling functionality?
What you are seeking is gradient ramps, and that is not something the
current themer does. If you are interested we can certaintly
bang one together on the community section. I imagine the SLD will be
fairly interesting for the color ranges - we would need to make an
expression
that calculates the colors in between two end points. We should check
if geotools has defined a color( r, g, b) function yet.
As luck would have it, I am currently making my mind up on how to provide user
interfaces for more styling options. In particular uDig still lacks a
comfortable UI for styling coverages, particularly grid coverages (e.g. remote
sensing images). Being able to style a coverage using color ramps is certainly
one important aspect of this.
I have chosen a similar approach as uDig (property pages) for a UI mockup to
build such "themers", so I might be able to contibute at least some UI code or
UI ideas to this discussion.
Very cool, the user interface we have there now is extensible and is set
up to allow for FeatureTypes, GridCoverages etc...
I havn't yet looked how exactly the existing themer pages create SLD
code/files(?) out of the user's setting, but my idea is to build generic
styling property pages that would be using some style factoy to create SLD
objects or whatever needed objects from the user's selections. This way the UI
could be generic (not tied to uDig alone), and this is what I intended for
GeoWidgets.
You are welcome to use what we have as a starting point.
I'm not yet sure this makes sense or is possible at all, but I'm playing in this
field in order to find out.
Have fun and let us know ;-)
P.S. Speaking about styling: I have tested the ColorBrewer page and find it is
nice and easy to use for beginners, although an advanced styler (as me) would
certainly have the need to define custom ramps etc. However the suitability
buttons (e.g. suitable for color-blind, printing, copying, CRT, LCD, ...) are
somewhat questionable. As an example, those palettes marked as unsuitable for
LCD display nicely on my laptop's LCD (which is a low quality LCD for sure).
But still, the overall idea is good.
I think the LCD button marks what palettes are suitable for an LCD
monitor. For more details on the research
please visit the color brewer project (I think they actually do
measurements on real people for those numbers).
Cheers,
Jody
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