Python core.QgsRasterPipe类代码示例

    def testLayerRemovalBeforeRun(self):
        """test behavior when layer is removed before task begins"""
        path = os.path.join(unitTestDataPath(), 'raster', 'with_color_table.tif')
        raster_layer = QgsRasterLayer(path, "test")
        self.assertTrue(raster_layer.isValid())

        pipe = QgsRasterPipe()
        self.assertTrue(pipe.set(raster_layer.dataProvider().clone()))

        tmp = create_temp_filename('remove_layer.tif')
        writer = QgsRasterFileWriter(tmp)

        task = QgsRasterFileWriterTask(writer, pipe, 100, 100, raster_layer.extent(), raster_layer.crs())

        task.writeComplete.connect(self.onSuccess)
        task.errorOccurred.connect(self.onFail)

        # remove layer
        raster_layer = None

        QgsApplication.taskManager().addTask(task)
        while not self.success and not self.fail:
            QCoreApplication.processEvents()

        # in this case will still get a positive result - since the pipe is cloned before the task
        # begins the task is no longer dependent on the original layer
        self.assertTrue(self.success)
        self.assertFalse(self.fail)
        self.assertTrue(os.path.exists(tmp))

def clip_raster(raster, column_count, row_count, output_extent):
    """Clip raster to specified extent, width and height.

    Note there is similar utility in safe_qgis.utilities.clipper, but it uses
    gdal whereas this one uses native QGIS.

    :param raster: Raster
    :type raster: QgsRasterLayer

    :param column_count: Desired width in pixels of new raster
    :type column_count: Int

    :param row_count: Desired height in pixels of new raster
    :type row_count: Int

    :param output_extent: Extent of the clipped region
    :type output_extent: QgsRectangle

    :returns: Clipped region of the raster
    :rtype: QgsRasterLayer
    """
    provider = raster.dataProvider()
    pipe = QgsRasterPipe()
    pipe.set(provider.clone())

    base_name = unique_filename()
    file_name = base_name + ".tif"
    file_writer = QgsRasterFileWriter(file_name)
    file_writer.writeRaster(pipe, column_count, row_count, output_extent, raster.crs())

    return QgsRasterLayer(file_name, "clipped_raster")

    def read_from_qgis_native(self, qgis_layer):
        """Read raster data from qgis layer QgsRasterLayer.

            A stub is used now:
                save all data in a file,
                then call safe.read_from_file

            Raises:
                * TypeError         if qgis is not avialable
                * IOError           if can't store temporary file
                * GetDataError      if can't create copy of qgis_layer's
                                        dataProvider
        """
        base_name = unique_filename()
        file_name = base_name + '.tif'

        file_writer = QgsRasterFileWriter(file_name)
        pipe = QgsRasterPipe()
        provider = qgis_layer.dataProvider()
        if not pipe.set(provider.clone()):
            msg = "Cannot set pipe provider"
            raise GetDataError(msg)

        file_writer.writeRaster(
            pipe,
            provider.xSize(),
            provider.ySize(),
            provider.extent(),
            provider.crs())

        # Write keywords if any
        write_keywords(self.keywords, base_name + '.keywords')
        self.read_from_file(file_name)

 def raster_to_file(self, layer, filename):
     '''
     write the contents of the raster-layer to a file (tif)
     '''
     extent = layer.extent()
     width, height = layer.width(), layer.height()
     
     pipe = QgsRasterPipe()
     # setting renderer leads to export as rendered image (strange: causes conversion from grayscale to multicolor with 4 bands)
     # else raw data is written (in grayscale)
     #renderer = layer.renderer()
     provider = layer.dataProvider()
     
     #pipe.set(renderer.clone())
     pipe.set(provider.clone())
     
     # another possible way to pipe (take the referenced one), references the renderer as well 
     # -> causes wrong color bands while exporting (see some lines above)
     #pipe = layer.pipe()
     
     file_writer = QgsRasterFileWriter(filename)
     
     file_writer.writeRaster(pipe,
                             width,
                             height,
                             extent,
                             layer.crs())           

    def _add_raster_layer(self, raster_layer, layer_name, save_style=False):
        """Add a raster layer to the folder.

        :param raster_layer: The layer to add.
        :type raster_layer: QgsRasterLayer

        :param layer_name: The name of the layer in the datastore.
        :type layer_name: str

        :param save_style: If we have to save a QML too. Default to False.
        :type save_style: bool

        :returns: A two-tuple. The first element will be True if we could add
            the layer to the datastore. The second element will be the layer
            name which has been used or the error message.
        :rtype: (bool, str)

        .. versionadded:: 4.0
        """
        if not self.is_writable():
            return False, 'The destination is not writable.'

        output = QFileInfo(self.uri.filePath(layer_name + '.tif'))

        source = QFileInfo(raster_layer.source())
        if source.exists() and source.suffix() in ['tiff', 'tif']:
            # If it's tiff file based.
            QFile.copy(source.absoluteFilePath(), output.absoluteFilePath())

        else:
            # If it's not file based.
            renderer = raster_layer.renderer()
            provider = raster_layer.dataProvider()
            crs = raster_layer.crs()

            pipe = QgsRasterPipe()
            pipe.set(provider.clone())
            pipe.set(renderer.clone())

            file_writer = QgsRasterFileWriter(output.absoluteFilePath())
            file_writer.Mode(1)

            file_writer.writeRaster(
                pipe,
                provider.xSize(),
                provider.ySize(),
                provider.extent(),
                crs)

            del file_writer

        if save_style:
            style_path = QFileInfo(self.uri.filePath(layer_name + '.qml'))
            raster_layer.saveNamedStyle(style_path.absoluteFilePath())

        assert output.exists()
        return True, output.baseName()

def polygonize_gdal(
        raster,
        threshold_min=0.0,
        threshold_max=float('inf')):
    """
    Function to polygonize raster. Areas (pixels) with threshold_min <
    pixel_values < threshold_max will be converted to polygons.

    :param raster:  Raster layer
    :type raster: QgsRasterLayer

    :param threshold_min: Value that splits raster to flooded or not flooded.
    :type threshold_min: float

    :param threshold_max: Value that splits raster to flooded or not flooded.
    :type threshold_max: float

    :returns: Polygonal geometry
    :rtype: QgsGeometry
    """

    # save qgis raster to disk
    base_name = unique_filename()
    file_name = base_name + '.tif'
    file_writer = QgsRasterFileWriter(file_name)
    pipe = QgsRasterPipe()
    provider = raster.dataProvider()
    if not pipe.set(provider.clone()):
        msg = "Cannot set pipe provider"
        raise GetDataError(msg)
    file_writer.writeRaster(
        pipe,
        provider.xSize(),
        provider.ySize(),
        provider.extent(),
        provider.crs())

    (
        inside_file_name,
        inside_layer_name,
        outside_file_name,
        outside_layer_name
    ) = polygonize_thresholds(file_name, threshold_min, threshold_max)
    inside_layer = \
        QgsVectorLayer(inside_file_name, inside_layer_name, 'ogr')
    outside_layer = \
        QgsVectorLayer(outside_file_name, outside_layer_name, 'ogr')
    if inside_layer.featureCount() == 0:
        return None, None
    else:
        return inside_layer, outside_layer

    def run_raster_upload(self):
        # The selected layer should be a raster layer.
        layer = self.iface.activeLayer()
        if not isinstance(layer, QgsRasterLayer):
            pop_up_info("Error: you must select the raster layer")
            return

        fd, tiff_filename = tempfile.mkstemp(suffix='.tiff')
        os.close(fd)
        # ^^^ We just want the filename, not the opened file descriptor.

        provider = layer.dataProvider()
        pipe = QgsRasterPipe()
        pipe.set(provider.clone())
        file_writer = QgsRasterFileWriter(tiff_filename)
        file_writer.writeRaster(pipe,
                                provider.xSize(),
                                provider.ySize(),
                                provider.extent(),
                                provider.crs())
        # http://build-failed.blogspot.nl/2014/12/splitting-vector-and-raster-files-in.html
        # print(tiff_filename)

        # Optionally TODO: grab title from dialog.
        title = "Uploaded by the qgis plugin on %s" % (
            datetime.datetime.now().isoformat())

        form = urllib2_upload.MultiPartForm()
        form.add_field('title', title)
        form.add_field('organisation_id', str(self.selected_organisation))
        filename = os.path.basename(tiff_filename)
        form.add_file('raster_file', filename, fileHandle=open(tiff_filename, 'rb'))

        request = urllib2.Request('https://ggmn.un-igrac.org/upload_raster/')
        request.add_header('User-agent', 'qgis ggmn uploader')
        request.add_header('username', self.username)
        request.add_header('password', self.password)
        body = str(form)
        request.add_header('Content-type', form.get_content_type())
        request.add_header('Content-length', len(body))
        # print("content-length: %s" % len(body))
        request.add_data(body)

        fd2, logfile = tempfile.mkstemp(prefix="uploadlog", suffix=".txt")
        open(logfile, 'w').write(request.get_data())
        # print("Printed what we'll send to %s" % logfile)

        answer = urllib2.urlopen(request).read()
        # print(answer)
        # print("Uploaded geotiff to the server")
        pop_up_info("Uploaded geotiff to the server")

    def exportRasterLayer(self, layer, destinationFile, options=None):
        outputFormat = self.settings['rasterFormat'] if 'rasterFormat' in self.settings else 'GTiff'

        if os.path.splitext(destinationFile)[1] == '':
            formats = QgsRasterFileWriter.extensionsForFormat(outputFormat)
            if len(formats) > 0:
                destinationFile = '{}.{}'.format(destinationFile, formats[0])

        provider = layer.dataProvider()

        cols = provider.xSize()
        rows = provider.ySize()
        if not provider.capabilities() & QgsRasterDataProvider.Size:
            k = float(provider.extent().width()) / float(provider.extent().height())
            cols = RASTER_SIZE * k
            rows = RASTER_SIZE

        pipe = QgsRasterPipe()
        if not pipe.set(provider.clone()):
            QgsMessageLog.logMessage(self.tr('Failed to export layer "{layer}": Cannot set pipe provider.'.format(layer=layer.name())), 'QConsolidate', Qgis.Warning)
            return False, None

        nodata = {}
        for i in range(1, provider.bandCount() + 1):
            if provider.sourceHasNoDataValue(i):
                value = provider.sourceNoDataValue(i)
                nodata[i] = QgsRasterRange(value, value)

        nuller = QgsRasterNuller()
        for band, value in nodata.items():
            nuller.setNoData(band, [value])

        if not pipe.insert(1, nuller):
            QgsMessageLog.logMessage(self.tr('Failed to export layer "{layer}": Cannot set pipe nuller.'.format(layer=layer.name())), 'QConsolidate', Qgis.Warning)
            return False, None

        writer = QgsRasterFileWriter(destinationFile)
        writer.setOutputFormat(outputFormat)

        if options is not None:
            writer.setCreateOptions(options)

        success = True
        error = writer.writeRaster(pipe, cols, rows, provider.extent(), provider.crs())
        if error != QgsRasterFileWriter.NoError:
            QgsMessageLog.logMessage(self.tr('Failed to export layer "{layer}": {message}.'.format(layer=layer.name(), message=error)), 'QConsolidate', Qgis.Warning)
            success = False

        return success, destinationFile

  def test02_SaveAsGeoTIFF(self):
    """Save raster layer as a GeoTIFF file"""
    self._testAvailable() or self.skipTest("Not available")

    layer = self._testLayer(self.fileName)

    # write to a disk
    # ref. to the InaSAFE plugin
    provider = layer.dataProvider()
    pipe = QgsRasterPipe()
    assert pipe.set(provider.clone()), "cannot set provider to pipe"

    outfile = self._testDataPath(self.fileName, output=True)
    writer = QgsRasterFileWriter(outfile)
    assert not writer.writeRaster(pipe, provider.xSize(), provider.ySize(), provider.extent(), provider.crs()), "failed to write"
    assert os.path.exists(outfile), "output file cannot be found"

  def extractRasterLayer(self, tempDir):
    """Extract the raster from the current layer to a temporary GeoTiff file.

    Extracts a geotiff file that can be uploaded to maps engine. This approach
    ensures that we are able to upload any layer that QGIS has ability to read.

    Args:
      tempDir: str, path of directory where to extract the shapefile.
    Returns:
      a dictionary with file names as keys and file path as values.
    """
    layerName = unicode(self.lineEditLayerName.text())
    tempTifPath = os.path.join(tempDir, layerName + '.tif')

    currentLayer = self.iface.mapCanvas().currentLayer()
    self.iface.messageBar().pushMessage(
        'Google Maps Engine Connector',
        'Extracting data to a temporary geotiff file. Please wait...',
        level=QgsMessageBar.INFO)
    QCoreApplication.processEvents()

    pipe = QgsRasterPipe()
    provider = currentLayer.dataProvider()
    pipe.set(provider.clone())

    rasterWriter = QgsRasterFileWriter(tempTifPath)
    xSize = provider.xSize()
    ySize = provider.ySize()
    if xSize and ySize:
      error = rasterWriter.writeRaster(
          pipe, xSize, ySize, provider.extent(), provider.crs())
      if error != QgsRasterFileWriter.NoError:
        QgsMessageLog.logMessage(error, 'GMEConnector',
                                 QgsMessageLog.CRITICAL)
        return
    else:
      return

    filesToUpload = {}
    fileName = layerName + '.tif'
    filePath = os.path.join(tempDir, fileName)
    filesToUpload[fileName] = filePath
    return filesToUpload

    def testSuccess(self):
        """test successfully writing a layer"""
        path = os.path.join(unitTestDataPath(), 'raster', 'with_color_table.tif')
        raster_layer = QgsRasterLayer(path, "test")
        self.assertTrue(raster_layer.isValid())

        pipe = QgsRasterPipe()
        self.assertTrue(pipe.set(raster_layer.dataProvider().clone()))

        tmp = create_temp_filename('success.tif')
        writer = QgsRasterFileWriter(tmp)

        task = QgsRasterFileWriterTask(writer, pipe, 100, 100, raster_layer.extent(), raster_layer.crs())

        task.writeComplete.connect(self.onSuccess)
        task.errorOccurred.connect(self.onFail)

        QgsApplication.taskManager().addTask(task)
        while not self.success and not self.fail:
            QCoreApplication.processEvents()

        self.assertTrue(self.success)
        self.assertFalse(self.fail)
        self.assertTrue(os.path.exists(tmp))

def exportRaster(layer, count, layersFolder, feedback, iface, matchCRS):
    feedback.showFeedback("Exporting %s to PNG..." % layer.name())
    name_ts = (safeName(layer.name()) + unicode(count) +
               unicode(int(time.time())))

    # We need to create a new file to export style
    piped_file = os.path.join(tempfile.gettempdir(), name_ts + '_piped.tif')

    piped_extent = layer.extent()
    piped_width = layer.height()
    piped_height = layer.width()
    piped_crs = layer.crs()
    piped_renderer = layer.renderer()
    piped_provider = layer.dataProvider()

    pipe = QgsRasterPipe()
    pipe.set(piped_provider.clone())
    pipe.set(piped_renderer.clone())

    file_writer = QgsRasterFileWriter(piped_file)

    file_writer.writeRaster(pipe, piped_height, -1, piped_extent, piped_crs)

    # Export layer as PNG
    out_raster = os.path.join(layersFolder, safeName(layer.name()) + "_" +
                              unicode(count) + ".png")

    projectCRS = iface.mapCanvas().mapSettings().destinationCrs()
    if not (matchCRS and layer.crs() == projectCRS):
        # Extent of the layer in EPSG:3857
        crsSrc = layer.crs()
        crsDest = QgsCoordinateReferenceSystem(3857)
        try:
            xform = QgsCoordinateTransform(crsSrc, crsDest,
                                           QgsProject.instance())
        except:
            xform = QgsCoordinateTransform(crsSrc, crsDest)
        extentRep = xform.transformBoundingBox(layer.extent())

        extentRepNew = ','.join([unicode(extentRep.xMinimum()),
                                 unicode(extentRep.xMaximum()),
                                 unicode(extentRep.yMinimum()),
                                 unicode(extentRep.yMaximum())])

        # Reproject in 3857
        piped_3857 = os.path.join(tempfile.gettempdir(),
                                  name_ts + '_piped_3857.tif')
        qgis_version = Qgis.QGIS_VERSION

        old_stdout = sys.stdout
        sys.stdout = mystdout = StringIO()
        try:
            processing.algorithmHelp("gdal:warpreproject")
        except:
            pass
        sys.stdout = old_stdout

        params = {
            "INPUT": piped_file,
            "SOURCE_CRS": layer.crs().authid(),
            "TARGET_CRS": "EPSG:3857",
            "NODATA": 0,
            "TARGET_RESOLUTION": 0,
            "RESAMPLING": 2,
            "TARGET_EXTENT": extentRepNew,
            "EXT_CRS": "EPSG:3857",
            "TARGET_EXTENT_CRS": "EPSG:3857",
            "DATA_TYPE": 0,
            "COMPRESS": 4,
            "JPEGCOMPRESSION": 75,
            "ZLEVEL": 6,
            "PREDICTOR": 1,
            "TILED": False,
            "BIGTIFF": 0,
            "TFW": False,
            "MULTITHREADING": False,
            "COPY_SUBDATASETS": False,
            "EXTRA": "",
            "OUTPUT": piped_3857
        }

        warpArgs = {}

        lines = mystdout.getvalue()
        for count, line in enumerate(lines.split("\n")):
            if count != 0 and ":" in line:
                try:
                    k = line.split(":")[0]
                    warpArgs[k] = params[k]
                except:
                    pass

        try:
            processing.run("gdal:warpreproject", warpArgs)
        except:
            shutil.copyfile(piped_file, piped_3857)

        try:
            processing.run("gdal:translate", {"INPUT": piped_3857,
                                              "OUTSIZE": 100,
#.........这里部分代码省略.........