Sounds promising.
Thanks Alexandre and Roland
Now where did I put my 'do not disturb' sign.....?
Regards,
Zoltan
On 2021-10-15 11:13, Alexandre Neto wrote:
Ah! good to see that video put to good use :-)
Yes, Zoltan, all you ask seems possible to me. The secret is in the
way you prepare your coverage layer to iterate over the items. Check
the video comment as I forgot to explain one step in the video.
I also have this old blog post that covers dynamic size pages. The
expressions are a bit outdated. that is, there are now functions that
make the expressions easier:
https://gisunchained.wordpress.com/tag/atlas/
Alexandre Neto
QGIS Support
www.qcooperative.net <http://www.qcooperative.net>
On Fri, Oct 15, 2021 at 9:53 AM Roland Spielhofer <[email protected]> wrote:
Hi Zoltan,
I guess your first item is covered here:
https://www.youtube.com/watch?v=NCsnTt6uxXo
I call the video "Atlas on steroids" ;-)
Regards,
Roland
*Gesendet:* Freitag, 15. Oktober 2021 um 10:39 Uhr
*Von:* "Zoltan" <[email protected]>
*An:* "qgis-user" <[email protected]>
*Betreff:* [Qgis-user] QGIS Atlas gymnastics
Hi,
I wonder if someone can confirm if below is possible or not, using
the Atlas facilities QGIS 3.20.3 in WIndows 10.
Two issues, the second relying on the first.
*#1 Variable size Map Item.*
I would like to vary the size of the Map Item window, depending on
the zoom window of the Atlas page.
I can set the "Position and Size" using an Expression or an
attribute Field, but this seems to be fixed rather than dynamic
ie: Is it possible to have Expression and/or Field values dynamic
per Atlas coverage page?
*#2 Multiple Sub-maps per MapSheet.*
Is it possible to have an Atlas page layout such that (say) in the
top half of the page you have your zoomed map (as in #1 above) and
in the bottom half of that sheet-page you place n-mapboxes as
insets predefined as n-AOI rectangles inside the zoom-window in
the top of this MapPage?
*A practical example/use would be:*
Say you are doing an aerial analysis of a stretch of river and you
have identified areas of interest by placing oriented rectangles
around them.
You now want to show an overview of segments of the river, and
then a zoom-in to each identified AOI rectangle to show larger
scale prints below this river segment.
*Method could/would be to:*
Using the width of your intended page size, calculate the
length of river you can fit across 1 page of your Atlas. Let's
assume 1Km
Now a river meanders so you cannot run down the polyline
depicting the river, you need to rotate and cut the river to
the width of your atlas page.
This means your atlas Map-Item width will be constant, but the
height, due to curvatures in the river, will vary.
Once you have your oriented MBRs calculated along the river,
you can use these as your Atlas Coverage layer.
To show this with optimal page-area usage, you would need the
Atlas facility I describe in *#1 above*.
Now, along the river you will have pre-placed your oriented
AOI rectangles.
These will be much smaller rectangles than the 1Km
river-length Atlas Coverage rectangles.
Now, for each AOI rectangle inside the current 1Km coverage
rectangle, I want to show a larger scale image below the
current coverage rectangle.
If*#2 above* was possible and flexible, one could use the
calculated (current) bottom left paper coord of the coverage
rectangle to calculate the top-left position of the first AOI
area.
And so on across then down the remaining Atlas page for
subsequent AOI boxes, which will likely be of varying size.
I suppose this is rather like wanting an Atlas page-set within and
Atlas page.
Anyone achieved something like this?
Does this sound useful?
I guess, unless I've missed some facility in Atlas, I will be
doing this by using the Atlas facility to spit out carefully named
jpeg images, and then assembling the pages using Python and
LibreOffice (or something).
All thoughts/directions welcome.
Kind regards,
Zoltan
--
=============================================
Zoltan Szecsei GPrGISc 0031
Geograph (Pty) Ltd.
GIS and Photogrammetric Services
Cape Town, South Africa.
Mobile: +27-83-6004028 (Signal, not WhatsApp)
www.geograph.co.za <http://www.geograph.co.za>
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=============================================
Zoltan Szecsei GPrGISc 0031
Geograph (Pty) Ltd.
GIS and Photogrammetric Services
Cape Town, South Africa.
Mobile: +27-83-6004028 (Signal, not WhatsApp)
www.geograph.co.za
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