本文整理汇总了Python中qgis.core.QgsRasterLayer.keywords['value_map']方法的典型用法代码示例。如果您正苦于以下问题：Python QgsRasterLayer.keywords['value_map']方法的具体用法？Python QgsRasterLayer.keywords['value_map']怎么用？Python QgsRasterLayer.keywords['value_map']使用的例子？那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类qgis.core.QgsRasterLayer的用法示例。
在下文中一共展示了QgsRasterLayer.keywords['value_map']方法的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的Python代码示例。
示例1: reclassify
# 需要导入模块: from qgis.core import QgsRasterLayer [as 别名]
# 或者: from qgis.core.QgsRasterLayer import keywords['value_map'] [as 别名]
#.........这里部分代码省略.........
Defaults to None.
:type callback: function
:return: The classified raster layer.
:rtype: QgsRasterLayer
.. versionadded:: 4.0
"""
output_layer_name = reclassify_raster_steps['output_layer_name']
processing_step = reclassify_raster_steps['step_name']
output_layer_name = output_layer_name % layer.keywords['layer_purpose']
if exposure_key:
classification_key = active_classification(
layer.keywords, exposure_key)
thresholds = active_thresholds_value_maps(layer.keywords, exposure_key)
layer.keywords['thresholds'] = thresholds
layer.keywords['classification'] = classification_key
else:
classification_key = layer.keywords.get('classification')
thresholds = layer.keywords.get('thresholds')
if not thresholds:
raise InvalidKeywordsForProcessingAlgorithm(
'thresholds are missing from the layer %s'
% layer.keywords['layer_purpose'])
if not classification_key:
raise InvalidKeywordsForProcessingAlgorithm(
'classification is missing from the layer %s'
% layer.keywords['layer_purpose'])
ranges = {}
value_map = {}
hazard_classes = definition(classification_key)['classes']
for hazard_class in hazard_classes:
ranges[hazard_class['value']] = thresholds[hazard_class['key']]
value_map[hazard_class['key']] = [hazard_class['value']]
if overwrite_input:
output_raster = layer.source()
else:
output_raster = unique_filename(suffix='.tiff', dir=temp_dir())
driver = gdal.GetDriverByName('GTiff')
raster_file = gdal.Open(layer.source())
band = raster_file.GetRasterBand(1)
no_data = band.GetNoDataValue()
source = band.ReadAsArray()
destination = source.copy()
for value, interval in ranges.iteritems():
v_min = interval[0]
v_max = interval[1]
if v_min is None:
destination[np.where(source <= v_max)] = value
if v_max is None:
destination[np.where(source > v_min)] = value
if v_min < v_max:
destination[np.where((v_min < source) & (source <= v_max))] = value
# Tag no data cells
destination[np.where(source == no_data)] = no_data_value
# Create the new file.
output_file = driver.Create(
output_raster, raster_file.RasterXSize, raster_file.RasterYSize, 1)
output_file.GetRasterBand(1).WriteArray(destination)
output_file.GetRasterBand(1).SetNoDataValue(no_data_value)
# CRS
output_file.SetProjection(raster_file.GetProjection())
output_file.SetGeoTransform(raster_file.GetGeoTransform())
output_file.FlushCache()
del output_file
if not isfile(output_raster):
raise FileNotFoundError
reclassified = QgsRasterLayer(output_raster, output_layer_name)
# We transfer keywords to the output.
reclassified.keywords = layer.keywords.copy()
reclassified.keywords['layer_mode'] = 'classified'
value_map = {}
hazard_classes = definition(classification_key)['classes']
for hazard_class in reversed(hazard_classes):
value_map[hazard_class['key']] = [hazard_class['value']]
reclassified.keywords['value_map'] = value_map
reclassified.keywords['title'] = output_layer_name
check_layer(reclassified)
return reclassified