def getMapunitFeaturesForBoundingBox(config, outputDir, bbox, tileBbox=False, t_srs='EPSG:4326'):
""" Query USDA Soil Data Mart for SSURGO MapunitPolyExtended features with a given bounding box.
Features will be written to one or more shapefiles, one file for each bboxTile tile,
stored in the specified output directory. The filename will be returned as a string.
Will fetch SSURGO tabular data (see ssurgolib.attributequery.ATTRIBUTE_LIST for a list
of attributes) and join those data to the features in the final shapefiles(s).
@note Will silently exit if features already exist.
@param config onfigParser containing the section 'GDAL/OGR' and option 'PATH_OF_OGR2OGR'
@param outputDir String representing the absolute/relative path of the directory into which features should be written
@param bbox A dict containing keys: minX, minY, maxX, maxY, srs, where srs='EPSG:4326'
@param tileBoundingBox True if bounding box should be tiled if extent exceeds featurequery.MAX_SSURGO_EXTENT
@param t_srs String representing the spatial reference system of the output shapefiles, of the form 'EPSG:XXXX'
@return A list of strings representing the name of the shapefile(s) to which the mapunit features were saved.
@exception IOError if output directory is not a directory
@exception IOError if output directory is not writable
@exception Exception if bounding box area is greater than MAX_SSURGO_EXTENT
@exception Exception if no MUKEYs were returned
"""
if not os.path.isdir(outputDir):
raise IOError(errno.ENOTDIR, "Output directory %s is not a directory" % (outputDir,))
if not os.access(outputDir, os.W_OK):
raise IOError(errno.EACCES, "Not allowed to write to output directory %s" % (outputDir,))
outputDir = os.path.abspath(outputDir)
typeName = 'MapunitPolyExtended'
if tileBbox:
bboxes = tileBoundingBox(bbox, MAX_SSURGO_EXTENT)
sys.stderr.write("Dividing bounding box %s into %d tiles\n" % (str(bbox), len(bboxes)))
else:
if calculateBoundingBoxArea(bbox, t_srs) > MAX_SSURGO_EXTENT:
raise Exception("Bounding box area is greater than %f sq. meters" % (MAX_SSURGO_EXTENT,))
bboxes = [bbox]
outFiles = []
for bboxTile in bboxes:
minX = bboxTile['minX']; minY = bboxTile['minY']; maxX = bboxTile['maxX']; maxY = bboxTile['maxY']
bboxLabel = str(minX) + "_" + str(minY) + "_" + str(maxX) + "_" + str(maxY)
gmlFilename = "%s_bbox_%s-attr.gml" % (typeName, bboxLabel)
gmlFilepath = os.path.join(outputDir, gmlFilename)
if not os.path.exists(gmlFilepath):
sys.stderr.write("Fetching SSURGO data for sub bboxTile %s\n" % bboxLabel)
wfs = WebFeatureService(WFS_URL, version='1.0.0')
filter = "<Filter><BBOX><PropertyName>Geometry</PropertyName> <Box srsName='EPSG:4326'><coordinates>%f,%f %f,%f</coordinates> </Box></BBOX></Filter>" % (minX, minY, maxX, maxY)
gml = wfs.getfeature(typename=(typeName,), filter=filter, propertyname=None)
# Write intermediate GML to a file
intGmlFilename = "%s_bbox_%s.gml" % (typeName, bboxLabel)
intGmlFilepath = os.path.join(outputDir, intGmlFilename)
out = open(intGmlFilepath, 'w')
out.write(gml.read())
out.close()
# Parse GML to get list of MUKEYs
gmlFile = open(intGmlFilepath, 'r')
ssurgoFeatureHandler = SSURGOFeatureHandler()
xml.sax.parse(gmlFile, ssurgoFeatureHandler)
gmlFile.close()
mukeys = ssurgoFeatureHandler.mukeys
if len(mukeys) < 1:
raise Exception("No SSURGO features returned from WFS query. SSURGO GML format may have changed.\nPlease contact the developer.")
# Get attributes (ksat, texture, %clay, %silt, and %sand) for all components in MUKEYS
attributes = getParentMatKsatTexturePercentClaySiltSandForComponentsInMUKEYs(mukeys)
# Compute weighted average of soil properties across all components in each map unit
avgAttributes = computeWeightedAverageKsatClaySandSilt(attributes)
# Convert GML to GeoJSON so that we can add fields easily (GDAL 1.10+ validates GML schema
# and won't let us add fields)
tmpGeoJSONFilename = convertGMLToGeoJSON(config, outputDir, intGmlFilepath, typeName)
tmpGeoJSONFilepath = os.path.join(outputDir, tmpGeoJSONFilename)
# Join map unit component-averaged soil properties to attribute table in GML file
# gmlFile = open(intGmlFilepath, 'r')
# joinedGmlStr = joinSSURGOAttributesToFeaturesByMUKEY(gmlFile, typeName, avgAttributes)
# gmlFile.close()
tmpGeoJSONFile = open(tmpGeoJSONFilepath, 'r')
geojson = json.load(tmpGeoJSONFile)
tmpGeoJSONFile.close()
joinSSURGOAttributesToFeaturesByMUKEY_GeoJSON(geojson, typeName, avgAttributes)
# Write Joined GeoJSON to a file
out = open(tmpGeoJSONFilepath, 'w')
json.dump(geojson, out)
out.close()
# Convert GeoJSON to shapefile
filename = os.path.splitext(intGmlFilename)[0]
shpFilename = convertGeoJSONToShapefile(config, outputDir, tmpGeoJSONFilepath, filename, t_srs=t_srs)
# Delete intermediate files
os.unlink(intGmlFilepath)
os.unlink(tmpGeoJSONFilepath)
outFiles.append(shpFilename)
# TODO: join tiled data if tileBbox
return outFiles
def _getMapunitFeaturesForBoundingBoxTile(config, outputDir, bboxTile, typeName, currTile, numTiles):
minX = bboxTile['minX']; minY = bboxTile['minY']; maxX = bboxTile['maxX']; maxY = bboxTile['maxY']
bboxLabel = str(minX) + "_" + str(minY) + "_" + str(maxX) + "_" + str(maxY)
gmlFilename = "%s_bbox_%s-attr.gml" % (typeName, bboxLabel)
gmlFilepath = os.path.join(outputDir, gmlFilename)
geoJSONLayername = "%s_bbox_%s-attr" % (typeName, bboxLabel)
if not os.path.exists(gmlFilepath):
sys.stderr.write("Fetching SSURGO data for tile %s of %s, bbox: %s\n" % (currTile, numTiles, bboxLabel))
sys.stderr.flush()
wfs = WebFeatureService(WFS_URL, version='1.1.0', timeout=SSURGO_WFS_TIMEOUT_SEC)
filter = "<Filter><BBOX><PropertyName>Geometry</PropertyName> <Box srsName='EPSG:4326'><coordinates>%f,%f %f,%f</coordinates> </Box></BBOX></Filter>" % (minX, minY, maxX, maxY)
intGmlFilename = "%s_bbox_%s.gml" % (typeName, bboxLabel)
intGmlFilepath = os.path.join(outputDir, intGmlFilename)
ssurgoFeatureHandler = SSURGOFeatureHandler()
downloadComplete = False
downloadAttempts = 0
while not downloadComplete:
try:
gml = wfs.getfeature(typename=typeName, filter=filter, propertyname=None)
# Write intermediate GML to a file
out = open(intGmlFilepath, 'w')
out.write(gml.read())
out.close()
# Parse GML to get list of MUKEYs
gmlFile = open(intGmlFilepath, 'r')
xml.sax.parse(gmlFile, ssurgoFeatureHandler)
gmlFile.close()
downloadComplete = True
except xml.sax.SAXParseException as e:
# Try to re-download
downloadAttempts += 1
if downloadAttempts > SSURGO_GML_MAX_DOWNLOAD_ATTEMPTS:
raise Exception("Giving up on downloading tile {0} of {1} after {2} attempts. There may be something wrong with the web service. Try again later.".format(currTile, numTiles, downloadAttempts))
else:
sys.stderr.write("Initial download of tile {0} of {1} possibly incomplete, error: {0}. Retrying...".format(currTile, numTiles, str(e)))
sys.stderr.flush()
mukeys = ssurgoFeatureHandler.mukeys
if len(mukeys) < 1:
raise Exception("No SSURGO features returned from WFS query. SSURGO GML format may have changed.\nPlease contact the developer.")
# Get attributes (ksat, texture, %clay, %silt, and %sand) for all components in MUKEYS
attributes = getParentMatKsatTexturePercentClaySiltSandForComponentsInMUKEYs(mukeys)
# Compute weighted average of soil properties across all components in each map unit
avgAttributes = computeWeightedAverageKsatClaySandSilt(attributes)
# Convert GML to GeoJSON so that we can add fields easily (GDAL 1.10+ validates GML schema
# and won't let us add fields)
tmpGeoJSONFilename = convertGMLToGeoJSON(config, outputDir, intGmlFilepath, geoJSONLayername,
flip_gml_coords=True)
tmpGeoJSONFilepath = os.path.join(outputDir, tmpGeoJSONFilename)
# Join map unit component-averaged soil properties to attribute table in GeoJSON file
tmpGeoJSONFile = open(tmpGeoJSONFilepath, 'r')
geojson = json.load(tmpGeoJSONFile)
tmpGeoJSONFile.close()
joinSSURGOAttributesToFeaturesByMUKEY_GeoJSON(geojson, typeName, avgAttributes)
# Write joined GeoJSON to a file
out = open(tmpGeoJSONFilepath, 'w')
json.dump(geojson, out)
out.close()
# Delete intermediate files
os.unlink(intGmlFilepath)
return tmpGeoJSONFilepath
