<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Hi<div class=""><br class=""></div><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On 08 Jul 2016, at 4:07 PM, David Barkhuisen <<a href="mailto:dave@kirchhoffsurveyors.co.za" class="">dave@kirchhoffsurveyors.co.za</a>> wrote:</div><br class="Apple-interchange-newline"><div class="">
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Hi Tim, Zoltan<br class="">
<br class="">
Just a quick one with the query below.<br class="">
<br class="">
Will it not be easier to move both tables into postgis db.<br class="">
Add empty lat and long columns to B then using SQL update the table
to pull the data from A to B<br class="">
something like:<br class="">
<br class="">
UPDATE B<br class="">
SET B.long = A.long<br class="">
B.Lat = A.lat<br class="">
<br class="">
From A <br class="">
JOIN B <br class="">
ON ST_Intersects(A.geom, B.geom)<br class="">
<br class="">
Would that not be an easier method?<br class="">
<br class=""></div></div></blockquote><div><br class=""></div><div>Yes absolutely - my answer was more intended to be academic ("how could one do this in QGIS"). Given a choice doing it in PostGIS is going to be far more efficient...</div><div><br class=""></div><div>Regards</div><div><br class=""></div><div>Tim</div><div><br class=""></div><br class=""><blockquote type="cite" class=""><div class=""><div text="#000000" bgcolor="#FFFFFF" class="">
Regards<br class="">
David<br class="">
<br class="">
<br class="">
<div class="moz-cite-prefix">On 08/07/2016 12:37, Tim Sutton wrote:<br class="">
</div>
<blockquote cite="mid:8487A194-876F-4DDF-8F6E-32E8EADDA044@kartoza.com" type="cite" class="">
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Hi
<div class=""><br class="">
<div class="">
<blockquote type="cite" class="">
<div class="">On 08 Jul 2016, at 11:30 AM, Zoltan Szecsei
<<a moz-do-not-send="true" href="mailto:zoltans@geograph.co.za" class="">zoltans@geograph.co.za</a>>
wrote:</div>
<br class="Apple-interchange-newline">
<div class="">
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<div bgcolor="#FFFFFF" text="#000000" class=""> Hi again,<br class="">
OK - it's not an index thing. More than one 'a' polygon
has received the 'b' attribute from the wrong 'b'
polygon even though the coordinate is inside the correct
'b' polygon.<br class="">
<br class="">
So the next step is to suspect the index.intersects
result.<br class="">
</div>
</div>
</blockquote>
<div class=""><br class="">
</div>
<div class="">Could you share a small testable dataset that replicates
it? I made a noddy test dataset here when playing with it
last night which worked fine, but it only had 2 polygons in
it...</div>
<br class="">
<blockquote type="cite" class="">
<div class="">
<div bgcolor="#FFFFFF" text="#000000" class=""> Note the
coords are in LatLong "small numeric values. I can see
we are using a null-length box (ie: a point) to select
from 'b'.<br class="">
What is the internal precision of the QgsPoint?<br class="">
</div>
</div>
</blockquote>
<div class=""><br class="">
</div>
<div class="">the x and y properties of QgsPoint are both doubles...it
depends on your platform what that means but typically</div>
<div class=""><br class="">
</div>
<div class=""><a moz-do-not-send="true" href="http://qgis.org/api/2.6/classQgsPoint.html" class="">http://qgis.org/api/2.6/classQgsPoint.html</a></div>
<div class=""><br class="">
</div>
<div class="">According to wikipedia on a 64 bit machine it should be:</div>
<div class=""><br class="">
</div>
<div class="">
<ul style="margin: 0.3em 0px 0px 1.6em; padding: 0px;
list-style-image:
url(data:image/svg+xml,%3C%3Fxml%20version%3D%221.0%22%20encoding%3D%22UTF-8%22%3F%3E%0A%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20version%3D%221.1%22%20width%3D%225%22%20height%3D%2213%22%3E%0A%3Ccircle%20cx%3D%222.5%22%20cy%3D%229.5%22%20r%3D%222.5%22%20fill%3D%22%2300528c%22%2F%3E%0A%3C%2Fsvg%3E%0A);
color: rgb(37, 37, 37); font-family: sans-serif;
font-size: 14px;" class="">
<li style="margin-bottom: 0.1em;" class=""><a moz-do-not-send="true" href="https://en.wikipedia.org/wiki/Sign_bit" title="Sign bit" style="text-decoration: none; color:
rgb(11, 0, 128); background-image: none;
background-position: initial initial;
background-repeat: initial initial;" class="">Sign bit</a>:
1 bit</li>
<li style="margin-bottom: 0.1em;" class=""><a moz-do-not-send="true" href="https://en.wikipedia.org/wiki/Exponent" class="mw-redirect" title="Exponent" style="text-decoration: none; color: rgb(11, 0, 128);
background-image: none; background-position: initial
initial; background-repeat: initial initial;">Exponent</a> width:
11 bits</li>
<li style="margin-bottom: 0.1em;" class=""><a moz-do-not-send="true" href="https://en.wikipedia.org/wiki/Significand" title="Significand" style="text-decoration: none;
color: rgb(11, 0, 128); background-image: none;
background-position: initial initial;
background-repeat: initial initial;" class="">Significand</a> <a moz-do-not-send="true" href="https://en.wikipedia.org/wiki/Precision_%28arithmetic%29" class="mw-redirect" title="Precision (arithmetic)" style="text-decoration: none; color: rgb(11, 0, 128);
background-image: none; background-position: initial
initial; background-repeat: initial initial;">precision</a>:
53 bits (52 explicitly stored)</li>
</ul>
<div class=""><br class="">
</div>
<div class=""><br class="">
</div>
</div>
<br class="">
<blockquote type="cite" class="">
<div class="">
<div bgcolor="#FFFFFF" text="#000000" class=""> My coord
attributes are 'double Real 19,10' <br class="">
<br class="">
In a script, when you select with a point, what is the
snapping tolerance?<br class="">
</div>
</div>
</blockquote>
<div class=""><br class="">
</div>
<div class="">To use snapping you would need to use the QGIS snapping
api - otherwise absolute geometry operations are being done.</div>
<br class="">
<blockquote type="cite" class="">
<div class="">
<div bgcolor="#FFFFFF" text="#000000" class="">My project
CRS is epsg 4326 - so it should be OK.<br class="">
</div>
</div>
</blockquote>
<div class=""><br class="">
</div>
<div class="">Yup. If you wanted to be fancy, you could extract a layer
of the tie points (FptnLat. FptnLong) so that you can
actually visualise the points in relation to the polygons.
Maybe you have some that don't actually intersect a poly...</div>
<br class="">
<blockquote type="cite" class="">
<div class="">
<div bgcolor="#FFFFFF" text="#000000" class=""> <br class="">
FWIW, b.name is string 60 which is copied into a.name
string 32 - but the contents are shorter that 32
chars.<br class="">
</div>
</div>
</blockquote>
<div class=""><br class="">
</div>
<div class="">I think QGIS will just truncate it if the name is longer
than 32 chars.</div>
<div class=""><br class="">
</div>
<div class="">T</div>
<br class="">
<blockquote type="cite" class="">
<div bgcolor="#FFFFFF" text="#000000" class=""> <br class="">
Any thoughts anyone?<br class="">
<br class="">
Regards,<br class="">
Zoltan<br class="">
<br class="">
</div>
</blockquote>
</div>
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