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08.08.2016, 16:42, Margherita Di Leo kirjoitti:<br>
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<div dir="ltr">Ari,<br>
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<div class="gmail_quote">On Mon, Aug 8, 2016 at 3:01 PM, Ari
Jolma <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:ari.jolma@gmail.com" target="_blank">ari.jolma@gmail.com</a>></span>
wrote:<br>
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<div bgcolor="#FFFFFF" text="#000000"><span> 08.08.2016,
15:19, Margherita Di Leo kirjoitti:<br>
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<div>Dear all,<br>
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is there a simple way to create tiles with a
certain overlap?<br>
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</span> Do you mean by "overlap" the geographic area the
tiles should cover? gdal2tiles.py creates the tiles for
the area the source dataset covers. So you can control
the area through the source dataset.</div>
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<div>Thanks for your answer, sorry I'm not sure I understand
the methodology you are proposing. Let me explain what I'm
trying to do so that the problem is clearer. I have a
dataset that is a global coverage, e.g. GMTED [1]. That is
a tiled dataset. However for my processing chain I need
tiles that overlap on each other for a certain number of
pixels. This means that the area at the border of each
tile should be covered by the tile itself and by the
adjacent one to certain extent.<br>
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Ok. I've done similar thing when I needed to get overlapping tiles
to produce shaded relief tiles on the fly from a DEM. My processing
chain was: <br>
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1) define the wanted tile (rectangle)<br>
2) expand it by some amount<br>
3) grab the expanded tile from the source (GDAL Translate)<br>
4) process the expanded tile (in my case DEMProcessing)<br>
5) shrink the wanted tile<br>
6) grab the original wanted tile from the result of the processing
(GDAL Translate again)<br>
7) deliver the final product<br>
<br>
(BTW, I'll present this in my FOSS4G 2016 talk)<br>
<br>
As the first thought I'd do the same access the source dataset with
GDAL and grab the data as such rectangles as you need (not the
native tiles on the server) - i.e., your overlapping tiles.<br>
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<div>My method would be the following. I would create a
virtual mosaic and then create the tiles with this rule.
From the manual of gdal2tiles.py it is not clear to me if
i can obtain this result. What do you mean by "you can
control the area through the source dataset"?<br>
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I mean simply set the area of the source but it is not relevant here
since your problem is different.<br>
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I think you need to write your own code as gdal2tiles is probably
not the solution. <br>
<br>
Ari<br>
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<div>Thank you<br>
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[1] <a moz-do-not-send="true"
href="http://topotools.cr.usgs.gov/gmted_viewer/"
target="_blank">http://topotools.cr.usgs.gov/<wbr>gmted_viewer/</a>
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-- <br>
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<div><font color="#666666">Margherita Di Leo</font></div>
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