com.vividsolutions.jump.io

Class ShapefileWriter

java.lang.Object

com.vividsolutions.jump.io.ShapefileWriter

All Implemented Interfaces:

JUMPWriter

public class ShapefileWriter
extends Object
implements JUMPWriter

ShapefileWriter is a JUMPWriter specialized to write Shapefiles.

DataProperties for the ShapefileWriter write(DataProperties) interface:

Parameter	Meaning
OutputFile or DefaultValue	File name for the output .shp file
ShapeType	Dimentionality of the Shapefile - 'xy', 'xym' or 'xyz'. 'xymz' and 'xyzm' are the same as 'xyz'

NOTE: The input .dbf and .shx is assumed to be 'beside' (in the same directory) as the .shp file.

The shapefile writer consists of two parts: writing attributes (.dbf) and writing geometries (.shp).

JUMP columns are converted to DBF columns by:

JUMP Column	DBF column
STRING	Type 'C' length is size of longest string in the FeatureCollection
DOUBLE	Type 'N' length is 33, with 16 digits right of the decimal
INTEGER	Type 'N' length is 16, with 0 digits right of the decimal

For more information on the DBF file format, see the DBF Specification FAQ

Since shape files may contain only one type of geometry (POINT, MULTPOINT, POLYLINE, POLYGON, POINTM, MULTPOINTM, POLYLINEM, POLYGONM, POINTZ, MULTPOINTZ, POLYLINEZ, or POLYGONZ), the FeatureCollection must be first be normalized to one type:

First non-NULL geometry in FeatureCollection	Coordinate Dimensionality	Shape Type
POINT/MULTIPOINT	xy xym xyzm	MULTIPOINT MULTIPOINTM MULTIPOINTZ
LINESTRING/MULTILINESTRING	xy xym xyzm	POLYLINE POLYLINEM POLYLINEZ
POLYGON/MULTIPOLYGON	xy xym xyzm	POLYGON POLYGONM POLYGONZ

During this normalization process any non-consistent geometry will be replaced by a NULL geometry.

For example, if the shapetype is determined to be 'POLYLINE' any POINT, MULTIPOINT, or POLYGON geometries in the FeatureCollection will be replaced with a NULL geometry.

The coordinate dimensionality can be explicitly set with a DataProperties tag of 'ShapeType': 'xy', 'xym', or 'xyz' ('xymz' and 'xyzm' are pseudonyms for 'xyz'). If this DataProperties is unspecified, it will be auto set to 'xy' or 'xyz' based on the first non-NULL geometry having a Z coordinate.

Since JUMP and JTS do not currently support a M (measure) coordinate, it will always be set to 10E40 in the shape file (type 'xym' or 'xyzm'). This value represents the Measure "no data" value (page 2, ESRI Shapefile Technical Description). Since the 'NaN' DOUBLE values for Z coordinates is invalid in a shapefile, it is converted to '0.0'.

For more information on the shapefile format, see the ESRI Shapefile Spec

Field Summary

Fields

Modifier and Type	Field and Description
protected static com.vividsolutions.jts.algorithm.CGAlgorithms	cga

Constructor Summary

Constructors

Constructor and Description
ShapefileWriter() Creates new ShapefileWriter

Method Summary

Modifier and Type	Method and Description
int	guessCoorinateDims(com.vividsolutions.jts.geom.Geometry g) Returns: 2 for 2d (default) 4 for 3d - one of the oordinates has a non-NaN z value (3 is for x,y,m but thats not supported yet)
com.vividsolutions.jts.geom.GeometryCollection	makeSHAPEGeometryCollection(FeatureCollection fc) return a single geometry collection result.GeometryN(i) = the i-th feature in the FeatureCollection All the geometry types will be the same type (ie.
void	write(FeatureCollection featureCollection, DriverProperties dp) Main method - write the featurecollection to a shapefile (2d, 3d or 4d).

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

cga

protected static com.vividsolutions.jts.algorithm.CGAlgorithms cga

Constructor Detail

ShapefileWriter

public ShapefileWriter()

Creates new ShapefileWriter

Method Detail

write

public void write(FeatureCollection featureCollection,
                  DriverProperties dp)
           throws IllegalParametersException,
                  Exception

Main method - write the featurecollection to a shapefile (2d, 3d or 4d).

Specified by:

write in interface JUMPWriter

Parameters:

featureCollection - collection to write

dp - 'OutputFile' or 'DefaultValue' to specify where to write, and 'ShapeType' to specify dimentionality.

Throws:

IllegalParametersException

Exception

guessCoorinateDims

public int guessCoorinateDims(com.vividsolutions.jts.geom.Geometry g)

Returns:
2 for 2d (default)
4 for 3d - one of the oordinates has a non-NaN z value
(3 is for x,y,m but thats not supported yet)

Parameters:

g - geometry to test - looks at 1st coordinate

makeSHAPEGeometryCollection

public com.vividsolutions.jts.geom.GeometryCollection makeSHAPEGeometryCollection(FeatureCollection fc)
                                                                           throws Exception

return a single geometry collection
result.GeometryN(i) = the i-th feature in the FeatureCollection
All the geometry types will be the same type (ie. all polygons) - or they will be set to
NULL geometries

GeometryN(i) = {Multipoint,Multilinestring, or Multipolygon)

Parameters:

fc - feature collection to make homogeneous

Throws:

Exception