Changes between Version 1 and Version 2 of ShpTree
- Timestamp:
- Jan 28, 2009, 10:46:12 AM (14 years ago)
Legend:
- Unmodified
- Added
- Removed
- Modified
-
ShpTree
v1 v2 5 5 ---- 6 6 7 The ShpTree utility creates spatial index files (.qix) for a single shapefile. !MapServer will take advantage of these spatial index files to more rapidly identify the shapefiles that are needed to render a particular map extents.7 The shptree utility creates spatial index files (.qix) for a single shapefile. !MapServer will take advantage of these spatial index files to more rapidly identify the shapefiles that are needed to render a particular map extents. 8 8 9 9 Note that the .qix file does not provide any indexing for attribute queries, and is unrelated to the shapefile tile index created by tile4ms. … … 37 37 == Old vs. New Format == 38 38 39 At this time I am not sure what the differences are between old and new formats. The new format seems to be smaller in the cases I have tried. Hopefully the developers (Steve Lime / CarlAnderson) will add notes here.39 At this time I am not sure what the differences are between old and new formats. The new format seems to be smaller in the cases I have tried. Hopefully the developers (Steve Lime / Carl Anderson) will add notes here. 40 40 41 41 The New format is essentially the old format with a header added to explicitly indicate the byte order of the index, and a version number. This was in preparation for a (as of yet) unsubmitted work to add a integer based index in addition to the current (double) floating point index. … … 56 56 == History == 57 57 58 The original shapetree (in memory) indexing work was done by Frank Warmerdam within the ShapeLib distribution. It was adapted for MapServer, and improved by SteveLime and CarlAnderson. I am not sure which was responsible for the format rewrite (the new format).58 The original shapetree (in memory) indexing work was done by Frank Warmerdam within the !ShapeLib distribution. It was adapted for !MapServer, and improved by Steve Lime and Carl Anderson. I am not sure which was responsible for the format rewrite (the new format). 59 59 60 The original shptree only did native order indexes. Carl was trying to use Mapserver in a mixed server environment and added some byte swapping code. The old code was adjusted to guess byte order without changing the file format. The new format added a header with a tag "SQT", a byte order, and a format version number to allow future changes to be correctly detected.60 The original shptree only did native order indexes. Carl was trying to use !MapServer in a mixed server environment and added some byte swapping code. The old code was adjusted to guess byte order without changing the file format. The new format added a header with a tag "SQT", a byte order, and a format version number to allow future changes to be correctly detected. 61 61 62 62 At that time Carl also was having problems generating shptree indexes on machines with limited memory. The integer format is an attempt to reduce the index size and to speed up the indexing operation.