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我在 QGIS 中运行了一个 Python 脚本。它看起来像这样：

class Ranker(object):
    @staticmethod
    def haversine(lon1, lat1, lon2, lat2):
        """
        Calculate the great circle distance between two points 
        on the earth (specified in decimal degrees)
        """
        # convert decimal degrees to radians 
        lon1, lat1, lon2, lat2 = map(math.radians, [lon1, lat1, lon2, lat2])
        # haversine formula 
        dlon = lon2 - lon1 
        dlat = lat2 - lat1 
        a = math.sin(dlat/2)**2 + math.cos(lat1) * math.cos(lat2) * math.sin(dlon/2)**2
        c = 2 * math.asin(math.sqrt(a)) 
        km = 6367 * c
        return km

    @staticmethod
    def calculateDistance(featureProperty, layerEntrances):
        if featureProperty.geometry() is None:
            print("Null property geometry! Returning -1!")
            return -1
        shortestDistance = 1000
        featuresEntrances = layerEntrances.getFeatures()
        for featureEntrance in featuresEntrances:
            if featureEntrance.geometry() is None:
                print("Null entrance geometry! Skipping!")
                continue
            latEntrance = featureEntrance.geometry().centroid().asPoint().y()
            lonEntrance = featureEntrance.geometry().centroid().asPoint().x()
            latProperty = featureProperty.geometry().centroid().asPoint().y()
            lonProperty = featureProperty.geometry().centroid().asPoint().x()
            currentDistance = Ranker.haversine(lonEntrance, latEntrance, lonProperty, latProperty)
            if currentDistance < shortestDistance:
                shortestDistance = currentDistance
        return shortestDistance

    @staticmethod
    def importAndAnalyze(rowLimit = 3):
        layerProperties = iface.addVectorLayer("/Users/patrick/Downloads/DOR_Parcel/DOR_Parcel.shp", "Philly_City_Parcels", "ogr")
        if not layerProperties:
            print("layerProperties failed to load!")
        layerEntrances = iface.addVectorLayer("/Users/patrick/Downloads/Stations/philly-rail-stations-merged.shp", "Rail_Stations", "ogr")
        if not layerEntrances:
            print("layerEntrances failed to load!")
        features = layerProperties.getFeatures()
        counter = 0
        featuresSelected = []
        Path('/Users/patrick/Desktop/philly-property-rankings.csv').touch()
        with open('/Users/patrick/Desktop/philly-property-rankings.csv', 'a') as csvFile:
            csvWriter = csv.writer(csvFile, delimiter=',', quotechar='"', quoting=csv.QUOTE_NONNUMERIC)
            csvWriter.writerow(['Address STD', 'Lat','Lon', 'Distance'])
            for feature in features:
                if counter < rowLimit:
                    csvWriter.writerow([feature['ADDR_STD'], feature.geometry().centroid().asPoint().y(),feature.geometry().centroid().asPoint().x(), Ranker.calculateDistance(feature, layerEntrances)])
                    if counter % 100 == 0:
                        csvFile.flush()
                else:
                    break
                counter += 1
            csvFile.flush()

Ranker.importAndAnalyze(10000000)

问题是脚本处理了大约 57,000 行数据后，它会吐出这个错误：

Traceback (most recent call last):
  File "/Applications/QGIS.app/Contents/MacOS/../Resources/python/code.py", line 90, in runcode
    exec(code, self.locals)
  File "<input>", line 1, in <module>
  File "<string>", line 72, in <module>
  File "<string>", line 64, in importAndAnalyze
ValueError: Null geometry cannot be converted to a point.

我不明白这个错误是如何达到的。我的两个引用该None值的条件不应该足以跳过任何空地理值吗？

完全披露：我通常不是 Python 人。如果我遗漏了一些明显的东西，请善待。

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