[OpenLayers-Users] Is OpenLayers client-side only?

Matthew Perry perrygeo at gmail.com
Fri Dec 15 16:44:50 EST 2006


Charlie,

On 12/15/06, Okeefe, Charlie (Mission Systems) <Charlie.Okeefe at ngc.com> wrote:
> I'm hoping to have a couple architectural questions cleared up. Mainly,  is
> OpenLayers purely a client-side ajax package? Or does it include components
> that run on the server as well?

It is purely a client-side library that interfaces with a variety of
web mapping services.

> As I currently understand it, setting up a web-based map (using my own map
> rather than Google or Yahoo etc) will involve:
>
> o installing UMN MapServer on a server to handle the actual map data

You can also look at Geoserver or Mapnik which handle the same functionality.

> o installing ka-map on a server to handle tiling functionality

I'd suggest also taking a look at TileCache which handles the tiling
using a variety of different rendering engines (mapserver, mapnik, wms
servers)

> o including OpenLayers in the script of a web page
>
> This way, OpenLayers runs in the browser and accesses ka-map tiling code
> running on the server, which in turn calls MapServer.
>

TileCache works in roughly the same way .. If the tile is already
cached on the server, it will just give back the image .. It will only
call mapserver (or whatever your rendering engine is) if the tile has
not yet been rendered.


> Is this correct? Is ka-map currently a useful and/or desirable piece of this
> puzzle? Are there any diagrams or descripts you that could help clear this
> up?

I think you've got a good handle on the big picture. Of course the
devil's in the details ;-)

I think an intermediate tile caching mechanism is essential for slippy
map interfaces and will increase the speed of your app and decrease
the server load immensely. ka-map or Tilecache are both good choices
for this, although I prefer Tilecache because I like python alot more
than php and I find it a bit easier to set up than kamap.

-- 
Matthew T. Perry
GIS Analyst / Software Engineer
National Center for Ecological Analysis and Synthesis (NCEAS)
work: perry at nceas.ucsb.edu
web: http://www.perrygeo.net



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