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<p>I left this question for a few days because I hoped someone with
more technical knowledge than me of how Qgis works with this type
of data would be able to answer your question. As a user I don't
have the same technical insight as one of the developers who may
be reading this question and more familiar with data processing in
the software.<br>
</p>
<p>I currently work with projects that use large numbers of data
layers of raster type, however in my case they are all in files
that I have downloaded to my computer and loading locally, rather
than any type of data that could be accessed from an online
server.</p>
<p>I have found in experience with working with raster layers that
Qgis 3 is handling them quite differently from previous versions
(I have been using Qgis since 1.8). It was not until version 2.14
that I started working with the projects using these large numbers
of raster images, and have been using them through 2.14, 2.16 and
2.18 and now in releases of version 3.</p>
<p>The map projects I am working on cover a part of New Zealand
specifically a corridor around 6000 kilometres long and about 20
metres wide which is covered by geojpeg rasters varying from 0.4
to 0.1 metre per pixel resolution and the size of each raster is
generally 4800x7200 pixels.<br>
</p>
<p>The experience I had is that Qgis 3.x appears to be caching a lot
more raster data in memory than I saw with 2.x and it seems to be
caching every raster in my project, not just the ones that I am
displaying at the moment. It uses up the resources in my system a
lot faster than 2.x ever did. And if I use larger size raster
files, I have seen it run out of resources on the system more than
once. <br>
</p>
<p>So in terms of the way it consumes resources for rasters, my
experience is more related to the way I see it using up the
physical resources on my computer like the physical or virtual
memory. I ended up adding more RAM to my system and more swap disk
space to help deal with the extra drain on resources that has
happened since upgrading to version 3.<br>
</p>
<p>There is a section in the settings dialog that specifically
relates to rendering. I'm not completely confident this is the
type of situation that would be relevant to your scenario. It may
affect my situation more if I spent some time playing with these
settings (render caching for example) but it might not be so
relevant to you, unless the render caching is causing the software
to download a lot of raster data from your WMS server. You could
try experimenting with some of those settings.</p>
<div class="moz-cite-prefix">On 20/03/19 2:08 AM, Pascale Hutter
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CA4EB22E-FB1C-4572-AB18-F7BAF8312BBC@hintermannweber.ch">
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
Hi Patrick
<div class=""><br class="">
</div>
<div class="">Thanks for your interest! Its raster data of aerial
images (<a
href="https://shop.swisstopo.admin.ch/de/products/geoservice/swisstopo_geoservices/swisstopoWMS"
class="" moz-do-not-send="true">https://shop.swisstopo.admin.ch/de/products/geoservice/swisstopo_geoservices/swisstopoWMS</a>).
I often use this for small environmental projects of mine, where
I have no budget to buy any additional data. So far the 5’000
Megapixel were enough to work during the whole year. Now it was
finished up within a month, although I did much less work. </div>
<div class="">I did read, that the whole wms-layer part was newly
written for the QGIS version 3.x, so maybe this has something to
do with it? </div>
<div class=""><br class="">
</div>
<div class="">Thank you for any kind of help!</div>
<div class=""><br class="">
</div>
<div class="">Pascale</div>
<div class=""> </div>
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<blockquote type="cite" class="">
<div class="">Am 19.03.2019 um 13:33 schrieb Patrick Dunford
<<a href="mailto:enzedrailmaps@gmail.com" class=""
moz-do-not-send="true">enzedrailmaps@gmail.com</a>>:</div>
<br class="Apple-interchange-newline">
<div class="">
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charset=UTF-8" class="">
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<p class="">What is the type of data which is within
your wms layer. Is this vector or raster type of data?<br
class="">
</p>
<div class="moz-cite-prefix">On 19/03/19 12:59 AM,
Pascale Hutter wrote:<br class="">
</div>
<blockquote type="cite"
cite="mid:42FA060A-32BF-4855-8C85-09D681F826D1@hintermannweber.ch"
class="">
<meta http-equiv="Content-Type" content="text/html;
charset=UTF-8" class="">
Hi there,
<div class=""><br class="">
</div>
<div class="">I’m quite new to QGIS version 3, and was
before working with QGIS 2.18. I often use
wms-layer, where I purchase a certain data-volume
(p. ex. 5’000 pixel) to work with. However, with the
new QGIS 3.0 this data volume is used up far more
quickly. In QGIS 2.18 it lasted a lot longer. I was
wondering if any of you mades some similar
experiences? Do you have any idea, if there is a way
to change the settings so the data volume would last
longer again?</div>
<div class=""><br class="">
</div>
<div class="">Thank you very much for any
suggestions! </div>
<div class=""><br class="">
</div>
<div class="">
<div class="">Pascale</div>
</div>
<div class="">
<div class="">
<div style="letter-spacing: normal; orphans: auto;
text-align: start; text-indent: 0px;
text-transform: none; white-space: normal;
widows: auto; word-spacing: 0px;
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break-word; -webkit-nbsp-mode: space;
-webkit-line-break: after-white-space;" class="">
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auto; text-align: start; text-indent: 0px;
text-transform: none; white-space: normal;
widows: auto; word-spacing: 0px;
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break-word; -webkit-nbsp-mode: space;
-webkit-line-break: after-white-space;"
class="">
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auto; text-align: start; text-indent: 0px;
text-transform: none; white-space: normal;
widows: auto; word-spacing: 0px;
-webkit-text-stroke-width: 0px; word-wrap:
break-word; -webkit-nbsp-mode: space;
-webkit-line-break: after-white-space;"
class="">
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auto; text-align: start; text-indent: 0px;
text-transform: none; white-space: normal;
widows: auto; word-spacing: 0px;
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break-word; -webkit-nbsp-mode: space;
-webkit-line-break: after-white-space;"
class="">
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font-size: 12px; font-style: normal;
font-variant-caps: normal; font-weight:
normal; letter-spacing: normal; orphans:
auto; text-align: start; text-indent:
0px; text-transform: none; white-space:
normal; widows: auto; word-spacing: 0px;
-webkit-text-stroke-width: 0px;"
class=""><span class="" style="orphans:
2; widows: 2;"><font class=""
face="Arial"><br class="">
</font></span></div>
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font-size: 12px; font-style: normal;
font-variant-caps: normal; font-weight:
normal; letter-spacing: normal; orphans:
auto; text-align: start; text-indent:
0px; text-transform: none; white-space:
normal; widows: auto; word-spacing: 0px;
-webkit-text-stroke-width: 0px;"
class=""><br class="">
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