[OpenLayers-Users] Displaying the whole world centered on Pacific

[Pierre-Benoit Besse]

I think I know why I have the white lines, its because I display squares
from a POINT shapefile. The size of the squares is calculated to cover all
map (they are 28 km wide and aligned verticaly and horizontaly ocer all the
world). But when I generate tiles, the squares get drawn only on the tile on
which the point is, so those which should be drawn on 2 tiles get drawn on 1
only and that leave a white line on the other.

Thus, the white lines width vary according to the zoom. Did I make myself
clear ?

Unfortunately, I think its a "normal" problem, but maybe someone knows a
trick about this ?

Regards


2008/7/4 Paul Spencer <pagameba at gmail.com>:

> Sorry, forgot you were using mapserver.  There is no particular difference
> in this case, probably MapServer is easier because it doesn't require
> anything special in the map file.
>
> I don't know why you are getting white lines on the borders of your tiles.
>  If you grab the url from one of the tiles and load it directly, does the
> image have the white borders in it?  If yes then it is something to do with
> your mapserver map file.  If not, then it is some artefact coming from
> openlayers or css, you can use firefox and the firebug extension to inspect
> your tiles and see where the border is coming from.
>
> Cheers
>
> Paul
>
>
> On 4-Jul-08, at 11:26 AM, Pierre-Benoit Besse wrote:
>
>  I don't know much about layer types. Why a WMS layer would do better than
>> a MapServer layer with my problem ?
>>
>> I tried it anyway, replacing OpenLayers.Layer.MapServer with
>> OpenLayer.Layer.WMS for the population density layer, but it changed
>> nothing, I still have white lines on the borders of tiles.
>>
>> Cheers,
>>
>> Faldor
>>
>> 2008/7/4 Paul Spencer <pagameba at gmail.com>:
>> singleTile doesn't do anything special to support the wrapDateLine
>> property, the underlying mapping technology just doesn't know how to draw a
>> map that spans the date line.
>>
>> A feature enhancement of the singleTile mode when the wrapDateLine
>> property is set might be to actually have more than one tile where each tile
>> is lined up with the date line.  So there would be one 'singleTile' from the
>> left edge of the extent to the date line, one from first date line to the
>> next (and so on) and a final one from the date line to the right edge of the
>> extent.
>>
>> Unless you are willing to work on this, though, you may do better to set
>> up a tiled layer using WMS rather than a singleTile layer.
>>
>> Cheers
>>
>> Paul
>>
>>
>> On 4-Jul-08, at 10:21 AM, Pierre-Benoit Besse wrote:
>>
>> Thank you Paul, it works.
>>
>> But I have an other problem now. I have a point shapefile containing
>> population density. I display each point as a square to cover the entire map
>> without holes.
>> To do it I had to set the singleTile property of the layer to "true" or I
>> had white lines on tiles borders (the squares are drawn only on the tile
>> containing the point).
>>
>> But it doesn't work with a wrapDateLine to "true" too. It cuts the map at
>> long 180 (-180) and switches to one 'side' or the other, but it never
>> displays both side at once.
>>
>> Is there anything I can do about it ?
>>
>> P.S : I don't know if I made myself clear, if not please ask for details.
>>
>> 2008/7/3 Paul Spencer <pagameba at gmail.com>:
>> Hi Faldor,
>>
>> you do need to use -180 -> 180, but I think you can get this to work using
>> the wrapDateLine propery, see the wrapDateLine.html example and then set the
>> center of your map to a geographic location in the pacific.
>>
>> Cheers
>>
>> PAul
>>
>>
>>
>> On 3-Jul-08, at 11:30 AM, Faldor wrote:
>>
>>
>> Hi all,
>>
>> Is there a way to display a map of the whole world not centered on Europe
>> ?
>> Until today I defined the "maxExtent" property of my "map" object with
>> (-180, -90, 180, 90).
>> I wish to display it centered on Pacific but I tried (0,..,360,..)
>> (0,..,0,..) etc... and it didn't work. For exemple with (0,..,360,..) it
>> displays from 0 to 180 but cuts the rest.
>>
>> How can I solve this ?
>> I display data from a MapServer server, I tried to edit the EXTENT
>> property
>> in the mapserver's mapfile but it changed nothing.
>>
>> Best Regards,
>>
>> Faldor
>> --
>> View this message in context:
>> http://www.nabble.com/Displaying-the-whole-world-centered-on-Pacific-tp18260454p18260454.html
>> Sent from the OpenLayers Users mailing list archive at Nabble.com.
>>
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>>
>>
>>
>
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