ecohydrolib.spatialdata.utils Namespace Reference

Generic utilities for manipulating spatial data sets. More...

Functions
def	bboxFromString (bboxStr)
	Get bbox dictionary from comma separated string of the form '-76.769782 39.273610 -76.717498 39.326008'. More...
def	isValidSrs (srsString)
	Determine if spatial reference string is valid. More...
def	getEPSGStringForUTMZone (zone, isNorth)
	Get EPSG string, e.g. More...
def	getUTMZoneFromCoordinates (longitude, latitude)
	Determine the UTM zone for coordinate pair. More...
def	transformCoordinates
	Transform a pair of X,Y coordinates from one reference system to another. More...
def	getRasterExtentAsBbox (extentRasterFilepath)
	Determine raster extent and store it in a bbox along with the spatial reference system of the raster. More...
def	extractTileFromRasterByRasterExtent
	Extract a tile from a raster using the extent of another raster as the tile bounds. More...
def	extractTileFromRaster (config, outputDir, inRasterFilename, outRasterFilename, bbox)
	Extract a tile from a raster. More...
def	resampleRaster
	Resample raster from one spatial reference system and resolution to another. More...
def	rescaleRaster (config, outputDir, inRasterFilepath, outRasterFilename, scalar)
	Rescale DN values of raster. More...
def	convertGMLToShapefile (config, outputDir, gmlFilepath, layerName, t_srs)
	Convert a GML file to a shapefile. More...
def	convertGMLToGeoJSON
def	convertGeoJSONToShapefile
	Convert a GeoJSON file to a shapefile. More...
def	mergeFeatureLayers
	Combine vector feature files readable by OGR into a single feature layer. More...
def	convertFeatureLayerToShapefile
	Convert a vector feature file readible by OGR to a shapefile. More...
def	deleteShapefile (shpfilePath)
	Delete shapefile and its related files (.dbf, .prj, .shx) More...
def	getCoordinatesOfPointsFromShapefile (shpFilepath, layerName, pointIDAttr, pointIDs)
	Get WGS84 coordinates of point features in shapefile. More...
def	deleteGeoTiff (geoTiffPath)
	Delete GeoTIFF and its related files (.aux.xml) More...
def	isCoordinatePairInBoundingBox (bbox, coordinates)
	Determine whether coordinate pair lies within bounding box. More...
def	calculateBoundingBoxCenter (bbox)
	Calculate the central point of the bounding box. More...
def	calculateBoundingBoxArea
	Calculate bbox area in squared units of srs. More...
def	tileBoundingBox
	Break up bounding box into tiles if bounding box is larger than threshold. More...
def	getBoundingBoxForShapefile
	Return the bounding box, in WGS84 (EPSG:4326) coordinates, for the ESRI shapefile. More...
def	bufferBoundingBox (bbox, buffer)
	Buffer the bounding by a given percentage. More...
def	getMeterConversionFactorForLinearUnitOfGMLfile (gmlFilename)
	Get conversion factor for converting a GML file's linear unit into meters. More...
def	getMeterConversionFactorForLinearUnitOfShapefile (shpFilename)
	Get conversion factor for converting a shapefile's linear unit into meters. More...
def	getNodataValuesForRaster (filename)
	Get nodata value for each band in a raster. More...
def	getSpatialReferenceForRaster (filename)
	Get pixel size and unit for DEM. More...
def	getDimensionsForRaster (filename)
	Get number of columns and rows for raster. More...
def	getBoundingBoxForRaster (filename)
	Return the bounding box, in WGS84 (EPSG:4326) coordinates, for the raster dateset. More...
def	writeBboxPolygonToShapefile
	Write bbox to a shapfile. More...
def	writeCoordinatePairsToPointShapefile
	Write coordinates as a point shapefile. More...
def	copyRasterToGeoTIFF (config, outputDir, inRasterPath, outRasterName)
	Copy input raster from a location outside of outputDir to a GeoTIFF format raster stored in outputDir. More...

Variables
int	SHP_MINX = 0
int	SHP_MAXX = 1
int	SHP_MINY = 2
int	SHP_MAXY = 3
list	RASTER_RESAMPLE_METHOD = ['near', 'bilinear', 'cubic', 'cubicspline', 'lanczos', 'average', 'mode']
int	WGS84_EPSG = 4326
string	WGS84_EPSG_STR = 'EPSG:4326'
float	NORTH = 0.0
float	EAST = 90.0
float	BBOX_TILE_DIVISOR = 1.0
string	OGR_SHAPEFILE_DRIVER_NAME = 'ESRI Shapefile'
string	OGR_GEOJSON_DRIVER_NAME = 'GeoJSON'
dictionary	OGR_DRIVERS
tuple	EPSG_RE = re.compile('^epsg:\d+$')
tuple	GDAL_VERSION_RE = re.compile('^GDAL\s(\d{1,2})\.(\d{1,2})\.(\d{1,2}),\sreleased\s\d{4}/\d{2}/\d{2}\s*$')

Detailed Description

Generic utilities for manipulating spatial data sets.

Builds a task-oriented API, for select operations, on top of GDAL/OGR utilities, GDAL/OGR API, Proj API.

This software is provided free of charge under the New BSD License. Please see the following license information:

Copyright (c) 2013, University of North Carolina at Chapel Hill All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

• Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
• Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
• Neither the name of the University of North Carolina at Chapel Hill nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Author

Brian Miles brian.nosp@m._mil.nosp@m.es@un.nosp@m.c.ed.nosp@m.u

Todo:

Refactor raster and vector functions into their own sub-packages Refactor bounding box as class

Builds a task-oriented API, for select operations, on top of GDAL/OGR utilities, GDAL/OGR API, Proj API.

This software is provided free of charge under the New BSD License. Please see the following license information:

Copyright (c) 2013, University of North Carolina at Chapel Hill All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

• Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
• Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
• Neither the name of the University of North Carolina at Chapel Hill nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Author

Brian Miles brian.nosp@m._mil.nosp@m.es@un.nosp@m.c.ed.nosp@m.u

Todo:

Refactor raster and vector functions into their own sub-packages Refactor bounding box as class

Function Documentation

def ecohydrolib.spatialdata.utils.bboxFromString

(

bboxStr

)

Get bbox dictionary from comma separated string of the form '-76.769782 39.273610 -76.717498 39.326008'.

Parameters

bboxStr

String representing bounding box in WGS84 coordinates

Returns

Dict representing bounding box with keys: minX, minY, maxX, maxY, and srs

def ecohydrolib.spatialdata.utils.bufferBoundingBox	(		bbox,
			buffer
	)

Buffer the bounding by a given percentage.

Parameters

bbox	A dict containing keys: minX, minY, maxX, maxY, srs, where srs='EPSG:4326'
buffer	Float >= 0.0 representing number of degrees by which to buffer the bounding box; 0.0 = no buffer, 0.01 = 0.01 degree buffer

def ecohydrolib.spatialdata.utils.calculateBoundingBoxArea	(		bbox,
			srs = WGS84_EPSG_STR
	)

Calculate bbox area in squared units of srs.

Parameters

bbox	A dict containing keys: minX, minY, maxX, maxY, srs, where srs='EPSG:4326'
srs	String representing spatial reference system, in EPSG format, in which area should be calculated.

Returns

Float representing the bounding box area in square meters

def ecohydrolib.spatialdata.utils.calculateBoundingBoxCenter

(

bbox

)

Calculate the central point of the bounding box.

Parameters

bbox	A dict containing keys: minX, minY, maxX, maxY, srs, where srs='EPSG:4326'

Returns

Tuple of floats of the form (longitude, latitude)

def ecohydrolib.spatialdata.utils.convertFeatureLayerToShapefile	(		config,
			outputDir,
			featureFilepath,
			shapefileName,
			layerName = None,
			t_srs = 'EPSG:4326',
			overwrite = False
	)

Convert a vector feature file readible by OGR to a shapefile.

Will silently exit if output shapefile already exists

Parameters

config	A Python ConfigParser containing the section 'GDAL/OGR' and option 'PATH_OF_OGR2OGR'
outputDir	String representing the absolute/relative path of the directory into which shapefile should be written
featureFilepath	String representing the absolute path of the feature file to convert
layerName	String representing the name of the layer contained in the feature file to write to a shapefile. If none, the base name of featureFilepath will be used
t_srs	String representing the spatial reference system of the output shapefile, of the form 'EPSG:XXXX'

Returns

String representing the name of the shapefile written

Exceptions

Exception

if the conversion failed.

def ecohydrolib.spatialdata.utils.convertGeoJSONToShapefile	(		config,
			outputDir,
			geoJSONFilepath,
			shapefileName,
			layerName = 'OGRGeoJSON',
			t_srs = 'EPSG:4326'
	)

Convert a GeoJSON file to a shapefile.

Will silently exit if shapefile already exists

   @param config A Python ConfigParser containing the section 'GDAL/OGR' and option 'PATH_OF_OGR2OGR'
   @param outputDir String representing the absolute/relative path of the directory into which shapefile should be written
   @param geoJSONFilepath String representing the absolute path of the GeoJSON file to convert
   @param layerName String representing the name of the layer contained in the GeoJSON file to write to a shapefile
   @param t_srs String representing the spatial reference system of the output shapefile, of the form 'EPSG:XXXX'

   @return String representing the name of the shapefile written

   @exception Exception if the conversion failed.

def ecohydrolib.spatialdata.utils.convertGMLToGeoJSON	(		config,
			outputDir,
			gmlFilepath,
			layerName,
			t_srs = 'EPSG:4326',
			flip_gml_coords = False
	)

Convert a GML file to a shapefile.  Will silently exit if GeoJSON already exists

    @param config A Python ConfigParser containing the section 'GDAL/OGR' and option 'PATH_OF_OGR2OGR'
    @param outputDir String representing the absolute/relative path of the directory into which GeoJSON should be written
    @param gmlFilepath String representing the absolute path of the GML file to convert
    @param layerName String representing the name of the layer contained in the GML file to write to a GeoJSON
    @param t_srs String representing the spatial reference system of the output GeoJSON, of the form 'EPSG:XXXX'
    
    @return String representing the name of the GeoJSON written

    @exception Exception if the conversion failed.

def ecohydrolib.spatialdata.utils.convertGMLToShapefile	(		config,
			outputDir,
			gmlFilepath,
			layerName,
			t_srs
	)

Convert a GML file to a shapefile.

Will silently exit if shapefile already exists

   @param config A Python ConfigParser containing the section 'GDAL/OGR' and option 'PATH_OF_OGR2OGR'
   @param outputDir String representing the absolute/relative path of the directory into which shapefile should be written
   @param gmlFilepath String representing the absolute path of the GML file to convert
   @param layerName String representing the name of the layer contained in the GML file to write to a shapefile
   @param t_srs String representing the spatial reference system of the output shapefile, of the form 'EPSG:XXXX'

   @return String representing the name of the shapefile written

   @exception Exception if the conversion failed.

def ecohydrolib.spatialdata.utils.copyRasterToGeoTIFF	(		config,
			outputDir,
			inRasterPath,
			outRasterName
	)

Copy input raster from a location outside of outputDir to a GeoTIFF format raster stored in outputDir.

Parameters

config	A Python ConfigParser containing the section 'GDAL/OGR' and option 'PATH_OF_GDAL_TRANSLATE'
outputDir	String representing the absolute/relative path of the directory into which shapefile should be written
inRasterPath	String representing path of input raster
outRasterName	String representing name of output raster to be stored in outputDir

IOError if gdal_translate binary is not found/executable IOError if output directory does not exist or not writable IOError if input raster is not readable

def ecohydrolib.spatialdata.utils.deleteGeoTiff

(

geoTiffPath

)

Delete GeoTIFF and its related files (.aux.xml)

Parameters

geoTiffPath

– Path, including filename, of the GeoTIFF to be deleted

def ecohydrolib.spatialdata.utils.deleteShapefile

(

shpfilePath

)

Delete shapefile and its related files (.dbf, .prj, .shx)

Parameters

shpfilePath

– Path, including filename, of the shapefile to be deleted

def ecohydrolib.spatialdata.utils.extractTileFromRaster	(		config,
			outputDir,
			inRasterFilename,
			outRasterFilename,
			bbox
	)

Extract a tile from a raster.

Tile extent is defined by supplied bounding box with coordinates defined in WGS84 (EPSG:4326).

Note

Output raster will be in LZW-compressed GeoTIFF file.

Will silently return if output raster already exists.

Parameters

config	Python ConfigParser containing the section 'GDAL/OGR' and option 'PATH_OF_GDAL_TRANSLATE'
outputDir	String representing the absolute/relative path of the directory into which output raster should be written
inRasterFilename	String representing the name of the input raster
outRasterFilename	String representing the name of the output raster
bbox	A dict containing keys: minX, minY, maxX, maxY, srs, where srs='EPSG:4326' (WGS84)

def ecohydrolib.spatialdata.utils.extractTileFromRasterByRasterExtent	(		config,
			outputDir,
			extentRasterFilepath,
			inRasterFilepath,
			outRasterFilename,
			resampleMethod = 'near'
	)

Extract a tile from a raster using the extent of another raster as the tile bounds.

Note

Output raster will be in LZW-compressed GeoTIFF file.

Will delete existing output raster if it already exists, then perform the extraction

Parameters

config	Python ConfigParser containing the section 'GDAL/OGR' and option 'PATH_OF_GDAL_WARP'
outputDir	String representing the absolute/relative path of the directory into which output raster should be written
extentRasterFilepath	String representing the path of the extent raster
inRasterFilepath	String representing the path of the raster from which a tile will be extracted
outRasterFilename	String representing the name of the output raster
resampleMethod	String representing method to use to resample; one of: RASTER_RESAMPLE_METHOD

def ecohydrolib.spatialdata.utils.getBoundingBoxForRaster

(

filename

)

Return the bounding box, in WGS84 (EPSG:4326) coordinates, for the raster dateset.

Assumes raster exists and is readable. Code adapted from: http://svn.osgeo.org/gdal/trunk/gdal/swig/python/samples/gdalinfo.py

Parameters

filename

String representing the DEM file to read pixel size and units

Returns

A tuple of the form: (columns, rows) or None if raster could not be opened

Exceptions

IOError	if filename is not readable
Exception	if raster dataset failed to open

def ecohydrolib.spatialdata.utils.getBoundingBoxForShapefile	(		shapefileName,
			buffer = 0.0
	)

Return the bounding box, in WGS84 (EPSG:4326) coordinates, for the ESRI shapefile.

Assumes shapefile exists and is readable. Based on http://svn.osgeo.org/gdal/trunk/gdal/swig/python/samples/ogrinfo.py

Parameters

shapefileName	String representing the path of the shapefile whose bounding box should be determined.
buffer	Float >= 0.0 representing number of degrees by which to buffer the bounding box; 0.0 = no buffer, 0.01 = 0.01 degree buffer

Returns

A dict containing keys: minX, minY, maxX, maxY, srs, where srs='EPSG:4326'

def ecohydrolib.spatialdata.utils.getCoordinatesOfPointsFromShapefile	(		shpFilepath,
			layerName,
			pointIDAttr,
			pointIDs
	)

Get WGS84 coordinates of point features in shapefile.

Parameters

shpFilepath	String representing the path of the shapefile
layerName	String representing the name of the layer within the shapefile from to read points
pointIDAttr	String representing name of the attribute used to identify points
pointIDs	List of strings representing IDs of coordinate pairs

Exception if unable to read layer of shapefile, or if no feature(s) with given attribute value(s) were found in the shapefile

Returns

Tuple of floats of the form (longitude, latitude)

def ecohydrolib.spatialdata.utils.getDimensionsForRaster

(

filename

)

Get number of columns and rows for raster.

Uses GDAL library Code adapted from: http://svn.osgeo.org/gdal/trunk/gdal/swig/python/samples/gdalinfo.py

Parameters

filename

String representing the DEM file to read pixel size and units

Returns

A tuple of the form: (columns, rows) or None if raster could not be opened

Exceptions

IOError

if filename is not readable

def ecohydrolib.spatialdata.utils.getEPSGStringForUTMZone	(		zone,
			isNorth
	)

Get EPSG string, e.g.

"EPSG:32618" for UTM zone (WGS84)

    @param zone Integer representing UTM zone
    @param isNorth True if north

    @return String of the pattern "^EPSG:\d+$"

def ecohydrolib.spatialdata.utils.getMeterConversionFactorForLinearUnitOfGMLfile

(

gmlFilename

)

Get conversion factor for converting a GML file's linear unit into meters.

Parameters

gmlFilename

String representing the GML file

Returns

Float representing the conversion factor

Exceptions

IOError(errno.EACCES)

if the GML file cannot be opened

def ecohydrolib.spatialdata.utils.getMeterConversionFactorForLinearUnitOfShapefile

(

shpFilename

)

Get conversion factor for converting a shapefile's linear unit into meters.

Parameters

shpFilename

String representing the name of the shapefile

Returns

Float representing the conversion factor

Exceptions

IOError(errno.EACCES)

if the shapefile cannot be opened

def ecohydrolib.spatialdata.utils.getNodataValuesForRaster

(

filename

)

Get nodata value for each band in a raster.

Uses GDAL library Code adapted from: http://svn.osgeo.org/gdal/trunk/gdal/swig/python/samples/gdalinfo.py

Parameters

filename

String representing the DEM file path

Returns

List containing nodata values for each band

Exceptions

IOError

if filename is not readable

def ecohydrolib.spatialdata.utils.getRasterExtentAsBbox

(

extentRasterFilepath

)

Determine raster extent and store it in a bbox along with the spatial reference system of the raster.

Parameters

extentRasterFilepath

String representing the path of the raster whose extent we are interested in

Returns

Dict representing bounding box with keys: minX, minY, maxX, maxY, and srs

IOError(errno.ENOENT) if extentRasterFilepath does not exist IOError(errno.EACCESS) if extentRasterFilepath is not readable

def ecohydrolib.spatialdata.utils.getSpatialReferenceForRaster

(

filename

)

Get pixel size and unit for DEM.

Uses GDAL library Code adapted from: http://svn.osgeo.org/gdal/trunk/gdal/swig/python/samples/gdalinfo.py

Parameters

filename

String representing the DEM file path

Returns

A tuple of the form: (pixelWidth, pixelHeight, linearUnitsName, linearUnitsConversionFactor, WKT SRS string, EPSG SRS string)

Exceptions

IOError

if filename is not readable

def ecohydrolib.spatialdata.utils.getUTMZoneFromCoordinates	(		longitude,
			latitude
	)

Determine the UTM zone for coordinate pair.

Parameters

longitude	Float representing WGS84 longitude
latitude	Float representing WGS84 latitude

Returns

Tuple of the form (zone number, true if north)

def ecohydrolib.spatialdata.utils.isCoordinatePairInBoundingBox	(		bbox,
			coordinates
	)

Determine whether coordinate pair lies within bounding box.

Parameters

bbox	A dict containing keys: minX, minY, maxX, maxY, srs, where srs='EPSG:4326'
coordinates	List of tuples of floats of the form (longitude, latitude), in WGS84

Returns

True if coordinates pair is within bounding box

def ecohydrolib.spatialdata.utils.isValidSrs

(

srsString

)

Determine if spatial reference string is valid.

Currently, only strings of the form 'EPSG:X...X' are valid.

Parameters

srsString

Returns

True if valid, False if invalid

def ecohydrolib.spatialdata.utils.mergeFeatureLayers	(		config,
			outputDir,
			featureFilepaths,
			outLayerName,
			outFormat = 'GeoJSON',
			keepOriginals = False,
			t_srs = 'EPSG:4326',
			overwrite = False
	)

Combine vector feature files readable by OGR into a single feature layer.

Parameters

config	A Python ConfigParser containing the section 'GDAL/OGR' and option 'PATH_OF_OGR2OGR'
outputDir	String representing the absolute/relative path of the directory into which shapefile should be written
featureFilepaths	Array of strings representing the absolute path of the feature files to convert
outLayerName	String representing the name of the merged GeoJSON feature. Extension '.geojson' will be added.
outFormat	String representing output format supported by OGR listed in OGR_DRIVERS
keepOriginals	Boolean, if True, original feature layers will be retained (otherwise they will be deleted)
t_srs	String representing the spatial reference system of the output feature, of the form 'EPSG:XXXX'
overwrite	Boolean, if True any existing files will be overwritten

Returns

String representing the absolute path of the single feature file written

Exceptions

Exception

if OGR returned an error.

def ecohydrolib.spatialdata.utils.resampleRaster	(		config,
			outputDir,
			inRasterFilepath,
			outRasterFilename,
			s_srs,
			t_srs,
			trX,
			trY,
			resampleMethod = 'bilinear'
	)

Resample raster from one spatial reference system and resolution to another.

Note

Output raster will be in LZW-compressed GeoTIFF file.

Will silently return if output raster already exists.

Parameters

config	Python ConfigParser containing the section 'GDAL/OGR' and option 'PATH_OF_GDAL_WARP'
outputDir	String representing the absolute/relative path of the directory into which output raster should be written
inRasterFilepath	String representing the path of the input raster
outRasterFilename	String representing the name of the output raster
s_srs	String representing the spatial reference of the input raster, if s_srs is None, the input raster's spatial reference
t_srs	String representing the spatial reference of the output raster
trX	Float representing the X resolution of the output raster (in target spatial reference units)
trY	Float representing the Y resolution of the output raster (in target spatial reference units)
resampleMethod	String representing resampling method to use. Must be one of spatialdatalib.utils.RASTER_RESAMPLE_METHOD.

Exceptions

ConfigParser.NoSectionError
ConfigParser.NoOptionError
IOError(errno.ENOTDIR)	if outputDir is not a directory
IOError(errno.EACCESS)	if outputDir is not writable
ValueError	if trX or trY are not floating point numbers greater than 0
Exception	if a gdal_warp command fails

def ecohydrolib.spatialdata.utils.rescaleRaster	(		config,
			outputDir,
			inRasterFilepath,
			outRasterFilename,
			scalar
	)

Rescale DN values of raster.

Note

Output raster will be in LZW-compressed GeoTIFF file.

Will silently return if output raster already exists.

Parameters

config	Python ConfigParser containing the section 'GDAL/OGR' and option 'PATH_OF_GDAL_WARP'
outputDir	String representing the absolute/relative path of the directory into which output raster should be written
inRasterFilepath	String representing the path of the input raster
outRasterFilename	String representing the name of the output raster
scalar	Float representing scalar. Values can run from (-Inf, Inf).

Exceptions

ConfigParser.NoSectionError
ConfigParser.NoOptionError
IOError(errno.ENOTDIR)	if outputDir is not a directory
IOError(errno.EACCESS)	if outputDir is not writable
ValueError	if scalar is not a floating point number
Exception	if a gdal_calc.py command fails

def ecohydrolib.spatialdata.utils.tileBoundingBox	(		bbox,
			threshold,
			t_srs = WGS84_EPSG_STR,
			divisor = BBOX_TILE_DIVISOR
	)

Break up bounding box into tiles if bounding box is larger than threshold.

Bounding box must be defined by WGS84 lat,lon coordinates

Parameters

bbox	Dict containing keys: minX, minY, maxX, maxY, srs, where srs='EPSG:4326'
threshold	Float representing threshold area above which bounding box will be tiled. Units: sq. meters
t_srs	String representing spatial reference system, in EPSG format, in which area should be calculated.
divisor	Float representing amount by which to divide tile sides, such that tile side = sqrt(threshold) / divisor

Returns

A list containing tiles defined as a dict containing keys: minX, minY, maxX, maxY, srs, where srs='EPSG:4326'

def ecohydrolib.spatialdata.utils.transformCoordinates	(		sourceX,
			sourceY,
			t_srs,
			s_srs = "EPSG:4326"
	)

Transform a pair of X,Y coordinates from one reference system to another.

Parameters

sourceX	A float representing the X coordinate
sourceY	A float representing the Y coordinate
t_srs	A string representing the spatial reference system of the output coordinates
s_srs	A string representing the spatial reference system, in EPSG format, of the input coordinates

Returns

A tuple of floats representing the transformed coordinates

def ecohydrolib.spatialdata.utils.writeBboxPolygonToShapefile	(		bbox,
			outputDir,
			layerName,
			overwrite = True
	)

Write bbox to a shapfile.

Parameters

bbox	A dict containing keys: minX, minY, maxX, maxY, srs, where srs='EPSG:4326'
outputDir	String representing the absolute/relative path of the directory into which shapefile should be written
layerName	String representing the name of the layer. Will be used as root of filename of output shapefile
overwrite	True if existing shapefile should be overwritten.

Returns

String representing the name of shapefile created (not the absolute path)

IOError is output directory is not a writable directory Exception if shapefile already exists Exception is failed to create shapefile

def ecohydrolib.spatialdata.utils.writeCoordinatePairsToPointShapefile	(		outputDir,
			layerName,
			pointIDAttr,
			pointIDs,
			coordinates,
			overwrite = True
	)

Write coordinates as a point shapefile.

Parameters

outputDir	String representing the absolute/relative path of the directory into which shapefile should be written
layerName	String representing the name of the layer. Will be used as root of filename of output shapefile
pointIDAttr	String representing name of the attribute used to identify points
pointIDs	List of strings representing IDs of coordinate pairs
coordinates	List of tuples of floats of the form (longitude, latitude), in WGS84
overwrite	True if existing shapefile should be overwritten.

Returns

String representing the name of shapefile created (not the absolute path)

IOError is output directory is not a writable directory Exception if shapefile already exists Exception is failed to create shapefile

Variable Documentation

float ecohydrolib.spatialdata.utils.BBOX_TILE_DIVISOR = 1.0

float ecohydrolib.spatialdata.utils.EAST = 90.0

tuple ecohydrolib.spatialdata.utils.EPSG_RE = re.compile('^epsg:\d+$')

tuple ecohydrolib.spatialdata.utils.GDAL_VERSION_RE = re.compile('^GDAL\s(\d{1,2})\.(\d{1,2})\.(\d{1,2}),\sreleased\s\d{4}/\d{2}/\d{2}\s*$')

float ecohydrolib.spatialdata.utils.NORTH = 0.0

dictionary ecohydrolib.spatialdata.utils.OGR_DRIVERS

Initial value:

= {OGR_SHAPEFILE_DRIVER_NAME: 'shp', 
               OGR_GEOJSON_DRIVER_NAME: 'geojson'}

string ecohydrolib.spatialdata.utils.OGR_GEOJSON_DRIVER_NAME = 'GeoJSON'

string ecohydrolib.spatialdata.utils.OGR_SHAPEFILE_DRIVER_NAME = 'ESRI Shapefile'

list ecohydrolib.spatialdata.utils.RASTER_RESAMPLE_METHOD = ['near', 'bilinear', 'cubic', 'cubicspline', 'lanczos', 'average', 'mode']

int ecohydrolib.spatialdata.utils.SHP_MAXX = 1

int ecohydrolib.spatialdata.utils.SHP_MAXY = 3

int ecohydrolib.spatialdata.utils.SHP_MINX = 0

int ecohydrolib.spatialdata.utils.SHP_MINY = 2

int ecohydrolib.spatialdata.utils.WGS84_EPSG = 4326

string ecohydrolib.spatialdata.utils.WGS84_EPSG_STR = 'EPSG:4326'