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Hi,<br>
Just by way of finality:<br>
<br>
The CRS of the polygon SHP was not what it was purported to be.<br>
I found that the .prj file was invalid when opening it in QGIS -
maybe next time I will first look at the maps I am given, rather
than just dive into python scripting. <br>
<br>
All working as expected, now.<br>
<br>
Thanks to those who gave ideas to try.<br>
<br>
Kind regards,<br>
Zoltan<br>
<br>
<div class="moz-cite-prefix">On 2024/08/25 19:44, Zoltan Szecsei via
QGIS-User wrote:<br>
</div>
<blockquote type="cite"
cite="mid:32bc6d4a-653c-4d08-b145-a367b60124de@geograph.co.za">
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
So as updated plan-of-attack as below.....<br>
<blockquote>
<blockquote type="cite">
<div style="background-color:#1e1f22;color:#bcbec4">
<pre
style="font-family:'JetBrains Mono',monospace;font-size:9,8pt;"><span
style="color:#7a7e85;">lyr_poly = QgsVectorLayer(poly_shp, '', 'Ogr')
</span><span style="color:#7a7e85;">lyr_poly_si = QgsSpatialIndex(lyr_poly.getFeatures(), flags=QgsSpatialIndex.FlagStoreFeatureGeometries)
</span><span style="color:#7a7e85;"># EPSG:4326
</span>point = QgsPointXY(lon, lat)
point_rect = QgsGeometry.fromPointXY(point).buffer(<span
style="color:#2aacb8;">0.001</span>, <span
style="color:#2aacb8;">5</span>).boundingBox()
<span style="color:#7a7e85;">#
</span>feature_ids = lyr_poly_si.intersects(point_rect) <span
style="color:#7a7e85;"># intersects wants rectangle
</span>requests = QgsFeatureRequest().setFilterFids(feature_ids)
<span style="color:#7a7e85;">#
</span>feature_idx = lyr_poly_si.nearestNeighbor(point, <span
style="color:#2aacb8;">10</span>, <span
style="color:#aa4926;">maxDistance</span>=<span
style="color:#2aacb8;">0.001</span>)
requestx = QgsFeatureRequest().setFilterFids(feature_idx)
</pre>
</div>
</blockquote>
</blockquote>
For the above code the lists feature_ids and feature_idx are
always empty.<br>
The Longitude and Latitude coords are correct, also for the box
created from the Point.<br>
<br>
I'd be grateful for any insight on why nothing is found.<br>
<br>
Thanks in advance,<br>
Zoltan<br>
<br>
<br>
<div class="moz-cite-prefix">On 2024/08/25 16:19, Zoltan Szecsei
via QGIS-User wrote:<br>
</div>
<blockquote type="cite"
cite="mid:4d547fda-c351-42fb-b54e-5a115c6b7222@geograph.co.za">
<meta http-equiv="content-type"
content="text/html; charset=UTF-8">
Hi,<br>
I'm doing my "once a year need to do something in python with
QGIS" :-/<br>
Using QGIS 3.38 and PyCharm.<br>
<br>
I have a SHP file with 28000 polygons.<br>
<b><font color="#ff8040">A SPREADSHEET file with 22000 Points
(for which I am making a SHP file and wanting attribute
vaues from underlying polygons)</font></b><br>
Both in EPSG:4326<br>
<br>
Without using QGIS processing, what is the quickest way to, for
each point 1 by 1, find the underlying polygon and read the
attribute field values of that polygon?<br>
The code snippet below is far too inefficient - but I cannot
find code that selects at XY and benefits from any spatial index
on the polygons.<br>
<blockquote>
<pre> <font face="Courier New, Courier, monospace">lyr_poly = QgsVectorLayer(polygon_shp, '', 'Ogr')
point = QgsPointXY(lon, lat)
request = QgsFeatureRequest().setFilterRect(lyr_poly.extent())
for feature in lyr_poly.getFeatures(request):
geom = feature.geometry()
if geom.contains(QgsGeometry.fromPointXY(point)):
lyr_poly.select(feature.id())
print(f"Feature with ID {feature.id()} is selected.")
break</font>
</pre>
</blockquote>
Thanks in advance,<br>
Zoltan<br>
<br>
<br>
<br>
<fieldset class="moz-mime-attachment-header"></fieldset>
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</pre>
</blockquote>
</blockquote>
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