smas1 / geoext-viewer

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WMS highlighting using OGC standards and SLD #77

Open GoogleCodeExporter opened 9 years ago

GoogleCodeExporter commented 9 years ago
See a good description here: http://trac.osgeo.org/openlayers/wiki/Highlighting 
(scroll to bottom for WMS highlighting as in this issue title)

WMS highlighting with client side SLD is a technique to highlight features on a 
map but without having to fetch the vector data (e.g. via WFS) from the server. 
With large amount of features this may save significant bandwidth and 
client-side processing within the browser.

From http://trac.osgeo.org/openlayers/wiki/Highlighting :

"One simulates highlighting by drawing a second WMS layer over a WMS layer. The 
trick is that a WMS can serve one (or more) features by using a FILTER in an 
SLD.

Pros
   * OGC compliant, so should work on any WMS supporting SLD.
   * Does not have an implicit limit on the number of vertices nor features, so is suitable for numerous complex polygons.
   * Can often be faster than WFS, as there's less data being transferred.
   *  Does not require a WFS server.
   * The WMS layer could easily incorporate labels as well as the highlighting.
   * It's possible to have different highlight-effects as the styling is includes in the SLD. 

Cons

    * Only works if your WMS server accepts SLD.
    * The resulting layer is WMS, which means no spatial geometry effects, e.g. zooming to the highlighted area.
    * requires an extra layer in your mapfile (or other WMS), which is able to retreive ALL geometries from all layers. "

Original issue reported on code.google.com by jus...@gmail.com on 31 Jan 2012 at 7:11

GoogleCodeExporter commented 9 years ago

Original comment by jus...@gmail.com on 31 Jan 2012 at 7:15

GoogleCodeExporter commented 9 years ago
Features herprioritiseren.

Original comment by jus...@gmail.com on 22 May 2012 at 2:42