So basically I've got this data that some other company sent me and instead of them sending it in line format like all the other companies, whatever troll works there just decided to send a 25meter buffer of the network

Is there a way to obtain the reverse of the buffer? Apparently ST_ApproximateMedialAxis would give me what I need but unfortunately amazon does not accept that extension. I'm also using QGIS

  • You are looking for the skeleton of the polygon - see gis.stackexchange.com/questions/tagged/skeleton for possible solutions – Ian Turton Jun 14 '18 at 10:39
  • I'm not sure but if your environment does not allow ST_ApproximateMedialAxis to create skeleton line, possible alternative would be HCMGIS plugin (for QGIS3.0). – Kazuhito Jun 14 '18 at 13:29
  • @Kazuhito that plugin says "NameError: name 'QgsProcessingFeedback' is not defined Traceback (most recent call last): File "/Users/pedrosantos/Library/Application Support/QGIS/QGIS3/profiles/default/python/plugins/HCMGIS/hcmgis_dialogs.py", line 168, in run message = hcmgis_medialaxis(self.iface,layer, selectedfield, density) File "/Users/pedrosantos/Library/Application Support/QGIS/QGIS3/profiles/default/python/plugins/HCMGIS/hcmgis_library.py", line 82, in hcmgis_medialaxis polygon = processing.run('qgis:saveselectedfeatures',parameters1) File – Luffydude Jun 14 '18 at 13:40
  • @Luffydude I cannot reproduce that error; the plugin have worked well so far. Will try to test it further to see if I can find the cause. – Kazuhito Jun 14 '18 at 13:44

Well the way I tackled the problem was merging the entire polygon into one, then using convert polygons to lines and then using the offset tool, using negative values to get the lines at the centre

It's not ideal but the original data isn't accurate enough anyway

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