MemoryError: std::bad_alloc

[qianmeil]

When I run the plugin using a few point for test，it works，but when I run this plugin with around 130000 latitude and longitude points，it report an error：
Traceback (most recent call last):
File "C:\Users/10784/AppData/Roaming/QGIS/QGIS3\profiles\default/python/plugins\HotspotAnalysis\hotspot_analysis.py", line 610, in run
w = DistanceBand(t, threshold1, p=2, binary=False)
File "C:\Users\10784\AppData\Roaming\Python\Python39\site-packages\pysal\lib\weights\distance.py", line 781, in init
self._band()
File "C:\Users\10784\AppData\Roaming\Python\Python39\site-packages\pysal\lib\weights\distance.py", line 848, in _band
self.dmat = self.kdtree.sparse_distance_matrix(
File "D:\PROGRA~1\apps\Python39\lib\site-packages\scipy\spatial_kdtree.py", line 865, in sparse_distance_matrix
return super().sparse_distance_matrix(
File "_ckdtree.pyx", line 1528, in scipy.spatial._ckdtree.cKDTree.sparse_distance_matrix
MemoryError: std::bad_alloc
Windows 11
QGIS：3.34.2
python：3.9.5
Looking forward to your reply！

[danioxoli]

Hello,

It looks like you have a memory error in the computation of the spatial weights matrix (https://stackoverflow.com/questions/8378797/stdbad-alloc-am-i-using-too-much-memory). The Plugin is tested for some thousand points only... and 130k double-precision point coordinates may be too much for the plugin.

For such datasets, I suggest moving to Python directly.

Daniele

[qianmeil]

Hello，

Thank you for your quick reply！
I have no idea how to run such a plugin on python directly，because there are many scripts and the plugin is related to QGIS，and I can not find out any useful information. I wonder if you can tell me detailed procedures or if you know any similar examples about running QGIS plugins on python directly.

Looking forward to your reply！

[danioxoli]

I suggest using directly PySAL (on which the Plugin is based). A relevant reference to start can be: https://geographicdata.science/book/notebooks/07_local_autocorrelation.html

Additionally, you may try other free software like GeoDa for computing LISA on your dataset. Have a look!

Best,

Daniele