Hello,
I am quite new in the geotools usergroup. First of all I want to say that
geotools is a really nice library with very interesting and useful functions.
In my actual project i worked with the indexed shapefile datastore.
In my tests the reading of point shapefile data seemed to be quite slow when
using the quadtree-index. When I searched for a solution I debugged the class
"ShapeFileIndexer.java". I found out that the BoundingBox of the of the points
was wrong.
Maybe someone wants to check out if it is really a bug or if the shapefiles
itself make the problems. They where generated with a software called FME.
The following workaround in the ShapeFileIndexer.java solved my problems (Look
for the comment "Workaround":
///////////////////////////////////////////////////////////////////////////////////////////////////////
private int buildQuadTree(ShapefileReader reader, File file, boolean
verbose)
throws IOException, StoreException {
byte order = 0;
if ((this.byteOrder == null) || this.byteOrder.equalsIgnoreCase("NM")) {
order = IndexHeader.NEW_MSB_ORDER;
} else if (this.byteOrder.equalsIgnoreCase("NL")) {
order = IndexHeader.NEW_LSB_ORDER;
} else {
throw new StoreException("Asked byte order '" + this.byteOrder
+ "' must be 'NL' or 'NM'!");
}
String ext = this.fileName.substring(this.fileName.lastIndexOf('.'));
String idxFileName = this.fileName.substring(0,
this.fileName.length() - 4)
+ (ext.equals(".shp") ? ".shx" : ".SHX");
FileInputStream fisIdx = new FileInputStream(idxFileName);
FileChannel channelIdx = fisIdx.getChannel();
IndexFile shpIndex = new IndexFile(channelIdx);
QuadTree tree=null;
int cnt = 0;
try{
int numRecs = shpIndex.getRecordCount();
ShapefileHeader header = reader.getHeader();
Envelope bounds = new Envelope(header.minX(), header.maxX(),
header.minY(), header.maxY());
tree = new QuadTree(numRecs, bounds, shpIndex);
Record rec = null;
while (reader.hasNext()) {
rec = reader.nextRecord();
/////Workarround
////because of wrong boundingbox at points
if(header.getShapeType()==ShapeType.POINT){
rec.maxX=rec.minX;
rec.maxY=rec.minY;
}
tree.insert(cnt++,
new Envelope(rec.minX, rec.maxX, rec.minY, rec.maxY));
if (verbose && ((cnt % 500) == 0)) {
System.out.print('.');
}
}
}finally{
channelIdx.close();
fisIdx.close();
shpIndex.close();
}
FileSystemIndexStore store = new FileSystemIndexStore(file, order);
store.store(tree);
return cnt;
}
///////////////////////////////////////////////////////////////////////////////////////////
--
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Gesellschaft für Geoinformationen
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Registergericht : Amtsgericht Kempten, HRB 6480
Geschäftsführer : Dipl.-Ing. Günter Kraus
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