I have a not-so-small GeoTIFF raster dataset. Here is what GDAL has to say about it:
$ gdalinfo japan.tif
Driver: GTiff/GeoTIFF
Files: japan.tif
Size is 14000, 14000
Coordinate System is:
GEOGCS["WGS 84",
DATUM["WGS_1984",
SPHEROID["WGS 84",6378137,298.2572235630016,
AUTHORITY["EPSG","7030"]],
AUTHORITY["EPSG","6326"]],
PRIMEM["Greenwich",0],
UNIT["degree",0.0174532925199433],
AUTHORITY["EPSG","4326"]]
Origin = (137.386330630776030,38.325757833006122)
Pixel Size = (0.000256020461176,-0.000256020461176)
Metadata:
AREA_OR_POINT=Area
TIFFTAG_DOCUMENTNAME=ER Mapper 6.4
TIFFTAG_IMAGEDESCRIPTION=ER Mapper GeoTiff raster translator V1.0: Band 1 = Red, Band 2 = Green, Band 3 = Blue
TIFFTAG_SOFTWARE=ER Mapper 6.4
TIFFTAG_XRESOLUTION=0
TIFFTAG_YRESOLUTION=0
Image Structure Metadata:
COMPRESSION=LZW
INTERLEAVE=PIXEL
Corner Coordinates:
Upper Left ( 137.3863306, 38.3257578) (137d23'10.79"E, 38d19'32.73"N)
Lower Left ( 137.3863306, 34.7414714) (137d23'10.79"E, 34d44'29.30"N)
Upper Right ( 140.9706171, 38.3257578) (140d58'14.22"E, 38d19'32.73"N)
Lower Right ( 140.9706171, 34.7414714) (140d58'14.22"E, 34d44'29.30"N)
Center ( 139.1784739, 36.5336146) (139d10'42.51"E, 36d32'1.01"N)
Band 1 Block=14000x20 Type=Byte, ColorInterp=Red
Band 2 Block=14000x20 Type=Byte, ColorInterp=Green
Band 3 Block=14000x20 Type=Byte, ColorInterp=Blue
I loaded it to PostGIS/WKT Raster table with regular blocking enabled in PostgreSQL 8.3 database running on Ubuntu 8.10 (32-bit) installed as a guest system under VirtualBox:
$ gdal2wktraster.py -r japan.tif -t japan_rb -o japan_rb.sql -k
$ psql -d test -f japan_rb.sql
The loader generated output file japan_rb.sql of size of 1.1 GB and it makes 700 records (raster tiles or blocks) in the database. The disk usage reported for the raster table is:
sistest=# SELECT relfilenode, relpages FROM pg_class WHERE relname = 'japan_rb';
relfilenode | relpages
-------------+----------
71700 | 5
(1 row)
I run simple test query:
$ psql -d test
test=# SET log_statement_stats TO 1;
SET
test=# SELECT rid FROM japan_rb WHERE RT_Width(rast) != 14000 OR RT_Height(rast) != 20;
rid
-----
(0 rows)
In the PostgreSQL log I got dumped a bunch of interesting statistics:
2009-03-27 15:23:38 GMT LOG: QUERY STATISTICS
2009-03-27 15:23:38 GMT DETAIL: ! system usage stats:
! 5.084838 elapsed 2.544159 user 2.468154 system sec
! [4.960310 user 5.204325 sys total]
! 0/0 [16/28160] filesystem blocks in/out
! 0/320190 [0/647479] page faults/reclaims, 0 [0] swaps
! 0 [0] signals rcvd, 0/0 [0/0] messages rcvd/sent
! 0/155 [9/327] voluntary/involuntary context switches
! buffer usage stats:
! Shared blocks: 74192 read, 0 written, buffer hit rate = 51.71%
! Local blocks: 0 read, 0 written, buffer hit rate = 0.00%
! Direct blocks: 0 read, 0 written
The virtual machine has assigned 1024 MB of RAM and one CPU Intel Xeon 3.2 GHz.
You are strongly welcome to share your comments?
Frank has just posted announcement about freshly released GDAL/OGR 1.7.0:
