utils.py

# -*- coding: utf-8 -*-

#******************************************************************************
#
# Metatools
# ---------------------------------------------------------
# Metadata browser/editor
# Copyright (C) 2011 BV (enickulin@bv.com)
# Copyright (C) 2011 NextGIS (info@nextgis.ru)
#
# This source is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free
# Software Foundation; either version 2 of the License, or (at your option)
# any later version.
#
# This code is distributed in the hope that it will be useful, but WITHOUT ANY
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
# details.
#
# A copy of the GNU General Public License is available on the World Wide Web
# at <http://www.gnu.org/copyleft/gpl.html>. You can also obtain it by writing
# to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
# MA 02111-1307, USA.
#
#******************************************************************************

from PyQt4.QtCore import *
from PyQt4.QtGui import *
from PyQt4.QtXml import *

from qgis.core import *
from qgis.gui import *

import os

from osgeo import gdal, ogr, osr

from metadata_provider import MetadataProvider

META_EXT = '.xml'
PREVIEW_SUFFIX = '_preview'

def getMetafilePath(layer):
  #not standard implementation in original plugin
  originalFilePath = unicode(layer.source())
  #originalFileName = os.path.splitext(originalFilePath)
  #metaFilePath = originalFileName[0] + META_EXT
  metaFilePath = originalFilePath + META_EXT
  return metaFilePath

def previewPathFromLayerPath(layerPath):
  settings = QSettings("NextGIS", "metatools")
  format_preview = settings.value("preview/format", "jpg")

  originalFileName = os.path.splitext(unicode(layerPath))
  metaFilePath = originalFileName[0] + PREVIEW_SUFFIX + '.' + format_preview
  return metaFilePath

def mdPathFromLayerPath(layerPath):
  #not standard implementation in original plugin
  #originalFileName = os.path.splitext(unicode(layerPath))
  #metaFilePath = originalFileName[0] + META_EXT
  metaFilePath = layerPath + META_EXT
  return metaFilePath

def getSupportedLayerNames():
  layermap = QgsMapLayerRegistry.instance().mapLayers()
  layerList = []
  for name, layer in layermap.iteritems():
    if MetadataProvider.IsLayerSupport(layer)[0]:
      layerList.append(layer.name())
  return layerList

def getSupportedLayers():
  layermap = QgsMapLayerRegistry.instance().mapLayers()
  layers = []
  for name, layer in layermap.iteritems():
    if MetadataProvider.IsLayerSupport(layer)[0]:
      layers.append((layer.name(), layer.source()))
  return layers

def getRasterLayerByName(layerName):
  layermap = QgsMapLayerRegistry.instance().mapLayers()
  for name, layer in layermap.iteritems():
    if layer.type() == QgsMapLayer.RasterLayer:
      if layer.providerType() != "gdal":
        continue
      if layer.name() == layerName:
        return layer
  return None

def getRasterLayerByPath(layerPath):
  layermap = QgsMapLayerRegistry.instance().mapLayers()
  for name, layer in layermap.iteritems():
    if layer.type() == QgsMapLayer.RasterLayer:
      if layer.providerType() != "gdal":
        continue
      if layer.source() == layerPath:
        return layer
  return None

# helper functions for raster metadata

def getGeneralRasterInfo(path):
  raster = gdal.Open(unicode(path).encode("utf8"))
  bands = raster.RasterCount

  width = raster.RasterXSize
  height = raster.RasterYSize

  gt = raster.GetGeoTransform()

  xMin = gt[0]
  yMin = gt[3] + width * gt[4] + height * gt[5]
  xMax = gt[0] + width * gt[1] + height * gt[2]
  yMax = gt[3]

  rasterSR = raster.GetProjectionRef()
  layerSR = osr.SpatialReference()
  layerSR.ImportFromWkt(rasterSR)
  #create wgs84 SR
  wgsSR = osr.SpatialReference()
  wgsSR.ImportFromEPSG(4326)

  #transform coord if layer CRS is defined otherwise assume WGS84
  if (layerSR is not None) and (not wgsSR.IsSame(layerSR)):
    transform = osr.CoordinateTransformation(layerSR, wgsSR)
    coord = transform.TransformPoints([(xMin, yMin), (xMax, yMax)])
    xMin = coord[0][0]
    yMin = coord[0][1]
    xMax = coord[1][0]
    yMax = coord[1][1]
    transform = None

  raster = None

  return bands, [xMin, yMin, xMax, yMax]

def getBandInfo(path, bandNumber):
  raster = gdal.Open(unicode(path).encode("utf8"))
  band = raster.GetRasterBand(bandNumber)

  min_value, max_value = band.ComputeRasterMinMax()
  if not min_value:
    min_value = 0
  if not max_value:
    max_value = 0

  dataType = band.DataType
  bytes_in_types = {0:-1, 1:8, 2:16, 3:16, 4: 32, 5: 32, 6: 32, 7:64, 8:16, 9:32, 10:32, 11: 64}
  dataType = bytes_in_types[dataType]

  #QMessageBox.information(QWidget(), "Metatools", "Min: "+str(min_value)+" Max: "+str(max_value)+" Dt: "+str(band.DataType) + " Byte: "+str(dataType)) #debug

  band = None
  raster = None

  return min_value, max_value, dataType

# helper functions for vector metadata
def getGeneralVectorInfo(path):
  ogrDataSource = ogr.Open(unicode(path).encode("utf8"))
  layer = ogrDataSource[0]

  #get extent and layer SR
  (xMin, xMax, yMin, yMax) = layer.GetExtent()
  layerSR = layer.GetSpatialRef()

  #create wgs84 SR
  wgsSR = osr.SpatialReference()
  wgsSR.ImportFromEPSG(4326)

  #transform coord if layer CRS is defined otherwise assume WGS84
  if (layerSR is not None) and (not wgsSR.IsSame(layerSR)):
    transform = osr.CoordinateTransformation(layerSR, wgsSR)
    coord = transform.TransformPoints([(xMin, yMin), (xMax, yMax)])
    xMin = coord[0][0]
    yMin = coord[0][1]
    xMax = coord[1][0]
    yMax = coord[1][1]
    transform = None

  layer = None
  ogrDataSource = None

  return [xMin, yMin, xMax, yMax]

# helper functions for XML processing
def createChild(element, childName):
  child = element.ownerDocument().createElement(childName)
  element.appendChild(child)
  return child

def getOrCreateChild(element, childName):
  child = element.firstChildElement(childName)
  if child.isNull():
    child = element.ownerDocument().createElement(childName)
    element.appendChild(child)
  return child

def insertAfterChild(element, childName, prevChildsName):
  child = element.ownerDocument().createElement(childName)

  # search previous element
  for elementName in prevChildsName:
    prevElement = element.lastChildElement (elementName)
    if not prevElement.isNull():
      element.insertAfter(child, prevElement)
      return child

  # if not found, simply append
  element.appendChild(child)
  return child

def getOrIsertAfterChild(element, childName, prevChildsName):
  child = element.firstChildElement(childName)
  if child.isNull():
    child = element.ownerDocument().createElement(childName)

    # search previous element
    for elementName in prevChildsName:
      prevElement = element.lastChildElement (elementName)
      if not prevElement.isNull():
        element.insertAfter(child, prevElement)
        return child

    # if not found, simply append
    element.appendChild(child)
  return child

def getOrIsertTopChild(element, childName):
  child = element.firstChildElement(childName)
  if child.isNull():
    child = element.ownerDocument().createElement(childName)
    element.insertBefore(child, QDomNode())
  return child

def getOrCreateTextChild(element):
  childTextNode = element.childNodes().at(0) # bad! need full search and type checker
  if childTextNode.isNull():
    childTextNode = element.ownerDocument().createTextNode("")
    element.appendChild(childTextNode)
  return childTextNode

# write raster information in metadata
def writeRasterInfo(dataFile, metadataFile):
  f = QFile(metadataFile)
  f.open(QFile.ReadOnly)
  metaXML = QDomDocument()
  metaXML.setContent(f)
  f.close()

  # general raster info
  bands, extent = getGeneralRasterInfo(dataFile)

  root = metaXML.documentElement()

  # geographic bounding box
  mdIdentificationInfo = getOrCreateChild(root, "identificationInfo")
  mdDataIdentification = getOrCreateChild(mdIdentificationInfo, "MD_DataIdentification")
  mdExtent = getOrCreateChild(mdDataIdentification, "extent")
  mdEXExtent = getOrCreateChild(mdExtent, "EX_Extent")
  mdGeorgaphicElement = getOrCreateChild(mdEXExtent, "geographicElement")
  mdGeoBbox = getOrCreateChild(mdGeorgaphicElement, "EX_GeographicBoundingBox")

  mdWestBound = getOrCreateChild(mdGeoBbox, "westBoundLongitude")
  mdCharStringElement = getOrCreateChild(mdWestBound, "gco:Decimal")
  textNode = getOrCreateTextChild(mdCharStringElement)
  textNode.setNodeValue(str(extent[0]))

  mdEastBound = getOrCreateChild(mdGeoBbox, "eastBoundLongitude")
  mdCharStringElement = getOrCreateChild(mdEastBound, "gco:Decimal")
  textNode = getOrCreateTextChild(mdCharStringElement)
  textNode.setNodeValue(str(extent[2]))

  mdSouthBound = getOrCreateChild(mdGeoBbox, "southBoundLatitude")
  mdCharStringElement = getOrCreateChild(mdSouthBound, "gco:Decimal")
  textNode = getOrCreateTextChild(mdCharStringElement)
  textNode.setNodeValue(str(extent[1]))

  mdNorthBound = getOrCreateChild(mdGeoBbox, "northBoundLatitude")
  mdCharStringElement = getOrCreateChild(mdNorthBound, "gco:Decimal")
  textNode = getOrCreateTextChild(mdCharStringElement)
  textNode.setNodeValue(str(extent[3]))

  # raster bands
  mdContentInfo = getOrCreateChild(root, "contentInfo")
  mdImageDescription = getOrCreateChild(mdContentInfo, "MD_ImageDescription")

  # drop all demensions
  while not (mdImageDescription.firstChildElement("dimension")).isNull():
    mdImageDescription.removeChild(mdImageDescription.firstChildElement("dimension"))

  mdDimension = insertAfterChild(mdImageDescription, "dimension", ["dimension", "contentType", "attributeDescription"]) #profile version

  # create new demensions
  for bandNumber in range(1, bands + 1):
    min_value, max_value, dt = getBandInfo(dataFile, bandNumber)
    #mdDimension = insertAfterChild(mdImageDescription, "dimension", ["dimension", "contentType", "attributeDescription"]) #standard version
    #mdBand = getOrCreateChild(mdDimension, "MD_Band") #standard version
    mdBand = createChild(mdDimension, "MD_Band") #profile version
    mdMaxValue = getOrCreateChild(mdBand, "maxValue")
    mdGcoReal = getOrCreateChild(mdMaxValue, "gco:Real")
    textNode = getOrCreateTextChild(mdGcoReal)
    textNode.setNodeValue(str(max_value))
    mdMinValue = getOrCreateChild(mdBand, "minValue")
    mdGcoReal = getOrCreateChild(mdMinValue, "gco:Real")
    textNode = getOrCreateTextChild(mdGcoReal)
    textNode.setNodeValue(str(min_value))
    mdBitsPerValue = getOrCreateChild(mdBand, "bitsPerValue")
    mdGcoInt = getOrCreateChild(mdBitsPerValue, "gco:Integer")
    textNode = getOrCreateTextChild(mdGcoInt)
    textNode.setNodeValue(str(dt))

  f = QFile(metadataFile)
  f.open(QFile.WriteOnly)
  stream = QTextStream(f)
  metaXML.save(stream, 2)
  f.close()

# write raster information in metadata
def writeVectorInfo(dataFile, metadataFile):
  f = QFile(metadataFile)
  f.open(QFile.ReadOnly)
  metaXML = QDomDocument()
  metaXML.setContent(f)
  f.close()

  # general raster info
  extent = getGeneralVectorInfo(dataFile)

  root = metaXML.documentElement()

  # geographic bounding box
  mdIdentificationInfo = getOrCreateChild(root, "identificationInfo")
  mdDataIdentification = getOrCreateChild(mdIdentificationInfo, "MD_DataIdentification")
  mdExtent = getOrCreateChild(mdDataIdentification, "extent")
  mdEXExtent = getOrCreateChild(mdExtent, "EX_Extent")
  mdGeorgaphicElement = getOrCreateChild(mdEXExtent, "geographicElement")
  mdGeoBbox = getOrCreateChild(mdGeorgaphicElement, "EX_GeographicBoundingBox")

  mdWestBound = getOrCreateChild(mdGeoBbox, "westBoundLongitude")
  mdCharStringElement = getOrCreateChild(mdWestBound, "gco:Decimal")
  textNode = getOrCreateTextChild(mdCharStringElement)
  textNode.setNodeValue(str(extent[0]))

  mdEastBound = getOrCreateChild(mdGeoBbox, "eastBoundLongitude")
  mdCharStringElement = getOrCreateChild(mdEastBound, "gco:Decimal")
  textNode = getOrCreateTextChild(mdCharStringElement)
  textNode.setNodeValue(str(extent[2]))

  mdSouthBound = getOrCreateChild(mdGeoBbox, "southBoundLatitude")
  mdCharStringElement = getOrCreateChild(mdSouthBound, "gco:Decimal")
  textNode = getOrCreateTextChild(mdCharStringElement)
  textNode.setNodeValue(str(extent[1]))

  mdNorthBound = getOrCreateChild(mdGeoBbox, "northBoundLatitude")
  mdCharStringElement = getOrCreateChild(mdNorthBound, "gco:Decimal")
  textNode = getOrCreateTextChild(mdCharStringElement)
  textNode.setNodeValue(str(extent[3]))

  f = QFile(metadataFile)
  f.open(QFile.WriteOnly)
  stream = QTextStream(f)
  metaXML.save(stream, 2)
  f.close()

def generatePreview(dataFile):
  # get raster
  rasterLayer = getRasterLayerByPath(dataFile)
  if not rasterLayer:
      rasterLayer = QgsRasterLayer(dataFile, "", True)

  #get size
  width = 512
  height = int(rasterLayer.height() * width / rasterLayer.width())
  preview = QPixmap(width, height)

  # generate preview
  rasterLayer.thumbnailAsPixmap(preview)
  preview.save(previewPathFromLayerPath(dataFile))