Just in terms of the image... Steve
>>> On 8/18/2008 at 6:30 AM, in message <[EMAIL PROTECTED]>, John Maurer <[EMAIL PROTECTED]> wrote: > Thanks for the suggestion, Daniel! I was unaware of the ANGLE parameter > in MapServer 5.0. One remaining concern I have, though, is how the angle > will be interpreted by MapServer? Will -90 degrees always point to the > South Pole regardless of the map projection I'm using (e.g. a polar > stereo map centered on the South Pole), or will it always just point to > the bottom of the map image regardless of the projection? i.e. Does > MapServer interpret the degrees spatially or just in terms of the image? > Unfortunately, if the latter is the case (which I suspect it probably > is) it will not solve my problem. Do you know? Thanks again! > Cheers, > John Maurer > > Daniel Morissette wrote: >> John Maurer wrote: >>> Dear MapServer Users, >>> Does anybody have experience displaying vectors in MapServer? By >>> "vectors", I don't mean the usual vector vs. raster difference. What >>> I mean is displaying data like wind vectors, which are point >>> locations that have both a direction (degrees) and magnitude (e.g. >>> meters per second). Usually these are displayed as arrows, which each >>> point in a certain direction and whose tails vary in length depending >>> on the magnitude each measurement. Is this possible in MapServer? >>> Thanks for any suggestions! >> >> You could bind the symbol size and angle to an attribute in your layer >> definition. >> >> If you can precompute the size in pixels based on the wind speed and >> store that to an 'arrowsize' attribute then you could use a layer >> defn's like this: >> >> LAYER >> TYPE POINT >> ... >> CLASS >> SYMBOL 'arrow' >> ANGLE [direction] >> SIZE [arrowsize] >> COLOR 0 0 0 >> END >> END >> >> >> If you can't precompute the arrow size in pixels, then you could use >> classes based on the wind speed attribute: >> >> LAYER >> TYPE POINT >> ... >> CLASSITEM 'windspeed' >> CLASS >> EXPRESSION ([windspeed] < 5) >> SYMBOL 'arrow' >> ANGLE [direction] >> SIZE 10 >> COLOR 0 0 0 >> END >> CLASS >> EXPRESSION ([windspeed] < 25) >> SYMBOL 'arrow' >> ANGLE [direction] >> SIZE 15 >> COLOR 0 0 0 >> END >> CLASS >> EXPRESSION ([windspeed] < 100) >> SYMBOL 'arrow' >> ANGLE [direction] >> SIZE 20 >> COLOR 0 0 0 >> END >> CLASS >> # No expression ... catch all for windspeed > 100 >> SYMBOL 'arrow' >> ANGLE [direction] >> SIZE 25 >> COLOR 0 0 0 >> END >> END >> >> >> Daniel _______________________________________________ mapserver-users mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/mapserver-users
