[OpenLayers-Users] GisCloud showing tons of vectors features on Web Browser

[Greg Allensworth]

At FOSS4G we learned a bit about how GeoMajas accomplishes this. It 
doesn't answer your question about how GISCloud does it, but may be a 
start on accomplishing it on your own maps using OpenLayers (or a hint 
that maybe GeoMajas can do what you want).

GeoMajas sends out the layer as raster, and the layer has a click event 
handler. This handler will fetch the geometry at the location and load 
it into the browser, then trigger the click on the vector feature. It 
isn't truly loading zillions of vectors, but the on-demand vector 
loading can simulate the effect pretty convincingly.

That could easily be done using WMS GetFeatureInfo, parsing the geometry 
from the response, and adding Features.

GeoMajas takes it a step further, in that the server does some 
calculation to determine whether there would be too many vectors, and if 
the payload is light enough it really will send vectors.

-- 
Greg Allensworth, Web GIS Developer
BS  A+  Network+  Security+  Linux+  Server+  ZCE-PHP
GreenInfo Network - Information and Mapping in the Public Interest
564 Market Street, Suite 510  San Francisco CA 94104
PH: 415-979-0343 x302  FX: 415-979-0371    email: gregor at greeninfo.org
Web: www.GreenInfo.org     www.MapsPortal.org

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