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Label display error in xmap2

Posted: Wed Nov 09, 2022 4:50 pm
by hegedus.tibor
Hi,

We recently moved to PTV2 from PTV1 and wanted to use the tile server with the same custom .ini config as we used with PTV1.
We found the topic about it and managed to insert the files to xServer2.
https://xserver.ptvgroup.com/forum/view ... f=5&t=1610

However we noticed a strange behavior with the labels layer as visible in the attached image (eg. city name should be "Budapest", not "apest").
On almost every zoom level there are tile borders, where the labels don't match.

Do you have any idea what causes this?
Or how can we debug the issue?

Best regards,
Tibor

Re: Label display error in xmap2

Posted: Thu Nov 10, 2022 7:42 am
by Bernd Welter
Hi Tibor,

Please ensure the following values are part of the render ini definition (works only in xMapServer 2):
[map]
; LabelMode set the mode to place the labels like town names, street names, street signs and background names.
; There are two label mode :
; LabelMode = 0 place as many labels in a view as possible.
; LabelMode = 1 place the labels stable, independent of the current view.
LabelMode = 1
Let us know how the result looks.

Here's also some info about the background of this issue:

With the older approach in times of xMapServer 1 each tile's labels have been placed without consideration of the neighbour tiles. Therefore we created the non-text tiles with square size and overlapped them with one big label driven layer tile with a size that was derived from the surrounding controls dimensions.

With xMapServer 2 the state-of-the art changed: we therefore invented the so-called stable labeling which enables the rendering engine to place the text labels in way that the assemblage of adjacent tiles leads to a continuous user experience. This was needed because more and more mapping interfaces are nowadays based on tile sources.

WIthin PTV Developer's Raster Maps API there's no on premise setup ;-) and therefore the profiles we provide already consider the stable rendering out of the box.

Bernd
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Re: Label display error in xmap2

Posted: Fri Nov 11, 2022 1:17 pm
by hegedus.tibor
Hi Bernd,

the suggested change fixed the issue.
Thank you for your support!

Br,
Tibor