[OpenLayers-Users] GIS Data Access to Maps

[Owen Densmore]

Thanks, that does indeed help us decide how to proceed.  We've been looking
at how to manage the geodata and the myriad formats and projections, and
whether or not to use "browser friendly" formats that javascript can parse
and use.

   -- Owen


On Mon, Aug 12, 2013 at 3:09 PM, Phil Scadden <p.scadden at gns.cri.nz> wrote:

> Adding Alex's comments - on a browser you have a number of important
> limitations to consider. The first is bandwidth - you have download both
> the js code and data you are going to display. Furthermore the data
> generally needs to be an ascii format so you lose indexing and have to
> contend with bulky representation of data. The second is javascript itself.
> While a lot of work has been done to improve it, it remains an
> interpretated, single-threaded language with all kind of limitations when
> it comes processing. Openlayers supports geojson, gml, kml (not kmz though)
> but in practise, dealing with a feature set with more than 500 bits of
> geometry gets very slow.
>
> For all the improvement in html5, the old mantra of do what can on the
> server still applies. To this end, what make web mapping hum is WMS/WFS
> servers (eg Geoserver, mapserver, ESRI arcGISServer). You load your GIS
> sets onto these servers and talk to them via openlayers with WMS/WFS
> protocols. For WMS, the client requests a map of a particular area and the
> server renders your GIS data and sends it back in image format. For WFS,
> you make a query and get the features back in say GML and render on the
> client.  (so you make sure the application only make requests for small
> data sets).
>
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