[OpenLayers-Users] Move to Openlayers

[Alexandre Dube]

Hi Peesjee,

  You don't need WFS in your case.  A WMS request on your ship position 
data would return a single image with your ships on it.  Like Till said, 
you only need to care about WMS.  You'll handle the rest with OpenLayers.

Alexandre

Peesjee wrote:
> Thx Till, 
>
> your answer clears a lot of questions for me. I am definitely a *newbie* in
> this area. I started reading about WMS and WFS yesterday, i even installed
> 'GeoServer', and succesfully mapped custom shapefile into the Geoserver. But
> then i got stuck thinking that only OpenLayers was responsible for the
> objects on the Map. I read about WFS, but i thought that was for retrieving
> data from existing data in maps (which my ships are not). I was clearly
> wrong.
>
> So can i say that: with GeoServer i must be able to show my own "maps" (tiff
> images), include the ships positions (with WFS) from our database...return
> this as one WMS layer... and add this layer in with Openlayers.
>
> I have to figure the WFS part of the puzzle then...
>
> ps: seeing your answer and mine now, this post doesn't handle much of
> openlayer, sorry for that...
>
> Greetz
> Peesjee
>
>
>
>
>
> Till Adams wrote:
>   
>> Hi,
>>
>> it is a WMS or WFS solution - that is what I probably would think as 
>> well:: There is a probalby UMN Mapserver or Geoserver (as WMS servers)  
>> solution behind, which handles the points (your ships) out of the 
>> database or a file. For this case, OL only has to handle one image, 
>> regardless whether you have 1, 3 or 2000 ships - this is a matter of the 
>> database or file feeding the WMS server behind, not of the client to 
>> render every single point.
>>
>> To explain the rough archtitecture behind - there is a WMS server like 
>> UMN or Geoserver (see www.osgeo.org for more info on them), they access 
>> your ship data (don't know where they come out, file or database?), you 
>> give them a marker and they create an image on the fly out of the ships 
>> - a WMS map request looks like that:
>>
>> http://www.webmapcenter.de/cgi-bin/mapserv?map=/var/data/www.webmapcenter.de%2Fnabu%2Fportale.map&TRANSPARENT=true&LAYERS=portale&FORMAT=image%2Fpng&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&STYLES=&EXCEPTIONS=application%2Fvnd.ogc.se_inimage&SRS=EPSG%3A900913&BBOX=761809.6422981643,6579508.301301379,831099.8084290314,6616771.352585221&WIDTH=1813&HEIGHT=975
>>
>> As you can see, there is are params like BoundingBox, layer, coordinate 
>> system (srid) and so on - they let you control the "place" (don't find a 
>> better word) you see on the map. The configuration of our WMS let you 
>> control the rendering of the images, e.g. different symbols and/or sizes 
>> based on any attribute(s).
>> The WMS server parses the request, accesses the data (your ships), 
>> creates a png (or gif, jpeg, ...) and sends it back to the requesting 
>> client.
>> More: see http://en.wikipedia.org/wiki/Web_Map_Service
>>
>> The request as above is directly taken from OL, so you only have to care 
>> about the WMS, not the rest, this will be done by OL for you.
>>
>> In the OL main file you bring the things together, the base layer from 
>> google and the WMS from your server - that's it, no worry about the 
>> amount of ships.
>>
>> BTW: I give you another strong reason why switching to openlayers makes 
>> sense: By changing one line of code you may switch from google basemaps 
>> to yahoo, virtual earth or any other base map service supported by OL, 
>> if any reason to do this comes up. Using the google API means using 
>> google maps ;-)
>>
>> Kind regards - Till
>>
>>     
>>> Hi,
>>>
>>> Let me explain my situation. I recently created an website showing
>>> current
>>> positions of ships with googlemaps. For a couple of reasons, we want to
>>> migrate to another solution. One of the reasons is performance. With
>>> googlemaps, i parse an xml (given by a webservice) and add/update markers
>>> for every ship to show. This slows down with the number of ships to show
>>> (example, sometimes we show more than 500 ships). To be honest, i'm not
>>> sure
>>> this is a good way to work...
>>>
>>> We are in contact with a company that offers a solution for us. They use
>>> Openlayers. We have seen a demo and its very fast. I dont think they add
>>> "markers" for every ship. Cause, when i zoom, the object also zooms, and
>>> then refresh to the correct size it was before. How do they do that? Its
>>> extremely fast, less than a second to show a 1000 of objects on a map.
>>>
>>> i'm given the task to investigate the possibilities of Openlayers, and
>>> decide whether we can implement everything ourselfs (with openlayers), or
>>> just buy the solution of that company. i'm afraid that, with my
>>> "solution",
>>> adding so many markers, the website would'nt be that fast.
>>>
>>> What is the best way to put 500 - 1000 "markers" on a map? (and refresh,
>>> when refreshing in googlemaps, i had to update the marker-objects to
>>> prevent
>>> flickering) Sometimes a have to draw lines between them (tracking). (i
>>> know
>>> of the image caching problem in IE)
>>>
>>> I see i can add Markers, GML, geoRSS. So, which one do i use? i could
>>> create
>>> a webservice that gives me a GML, so i only have to load it, but is this
>>> fast? or do i use my googlemaps way, adding markers and updating those
>>> markers (slow)?
>>>
>>> Greetz
>>> Peesjee
>>>
>>>
>>>   
>>>       
>> -- 
>> ----------------------------------------------------------
>> terrestris GmbH & Co. KG
>> Irmintrudisstrasse 17
>> 53111 Bonn
>> Germany
>>
>> Till Adams
>> Geschäftsführung
>>
>> Tel: +49 (0)228 / 962 899-52
>> Fax: +49 (0)228 / 962 899-57
>> adams at terrestris.de http://www.terrestris.de
>> Amtsgericht Bonn, HRA 6835
>> ---------------------------------------------------------
>>
>> Komplementärin:
>>
>> terrestris Verwaltungs GmbH
>>
>> vertreten durch:
>> Hinrich Paulsen, Till Adams
>>
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>>
>>
>>     
>
>   


-- 
Alexandre Dubé
Mapgears
www.mapgears.com