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orbisgis
H2 native raster functions
- [x] raster::geometry
- Convex hull of the raster (taking account of rotation)
- [x] ST_MetaData( RASTER ) ->ARRAY (Coordinate X, Coordinate Y, Width, Height, ScaleX, ScaleY, SkewX, SkewY, SRID, bands count)
- Get WKB metadata
- [x] ST_RasterFromImage( BLOB, upperLeftX, upperLeftY, scaleX, scaleY, skewX,
skewY, srid)
- Convert image stream into Raster using ImageIO (JAI can extend supported formats)
- [x] ST_ImageFromRaster( RASTER, FormatSuffix )
- FormatSuffix ex: png tiff
- ImageIO support also MimeType, but this is less user friendly.
- [x] ImageIO driver for reading WKBRaster as a Raster and/or BufferedImage.
- Image cannot be read if Blob is freed or connection is closed.
- [x] ImageIO ImageInputStream driver, that create ImageInputStream from JDBC Blob
- [x] ST_MakeEmptyRaster
- [ ] ST_AddBand with offdb image file (delivered with H2GIS)
- [x] ST_BandMetaData(raster rast, integer bandnum=1)
- [x] FILE_WRITE( lob, String ) ??
- [x] Image IO WKB Raster
- [ ] Image IO WKB Raster with offDb bands
- [x] LobDB, RenderedImage wrapping (in order to not break JAI processing chains)
The format of Raster is WKB Raster. This function must translate into another format, defined by the user.
Yes this is the inverse of ST_RasterFromImage. So you should call something like that:
SELECT ST_ImageFromRaster(ST_RASTERFROMIMAGE(FILE_READ('/home/user/aerial.png'), 150, 200, 1, 1, 0, 0, 4326), 'bmp') bmpData;
Maybe implement FILE_WRITE( lob, String ), to write image obtained through ImageFromRaster ?
Raster.toString() is converted into human readable metadata:
w:10 h:10 bands:3 srid:27572 x:0.00000 y:0.00000 scalex:1.00000 scaley:-1.00000 skewx:0.00000 skewy:0.00000
Currently WKB Image parsing is slow because there is absolutely no pixel cache. Here a sample of what is done currently:
I want RGB of pixel 500 red = Blob.getInputStream().skip(adressOfRedBandPixelZero) green = stream.skip(adressOfGreenPixelZero) blue = stream.skip(adressOfBluePixelZero)
I want RGB of Pixel 501 The problem here is the stream is in the blue band area. We have to reopen the stream and skip to the red band for pixel 501.
One solution
The class WKBRasterDataBuffer should cache the bands values for a row. The goal is to reset the minimum of times the stream and reduce the seek amount.
To be consistent with geometry drivers, ST_RasterFromFile function will be renamed by ST_WorldFileImageRead (eg SHPRead) and a new function ST_WorldFileImageWrite will be added.
Note : I don't want to use raster because it's a type (a category of datatype) and not a format like worldfile, geotiff.
ST_WorldFileImageWrite will have the following signature
ST_WorldFileImageWrite(RASTER, '/tmp/toto.png')
Usages
SELECT ST_WorldFileImageWrite(the_raster, '/tmp/toto.png') from myRasterTable limit 1;
SELECT ST_WorldFileImageWrite(the_raster,concat( concat( '/tmp/toto_', pkValue), '.png')) from myRasterTable;
@nico any input about this feature ? We are looking forward using raster in H2GIS ;-)
Note : The TIFF format will be integrated in JAVA 9 http://openjdk.java.net/jeps/262
Nice.
@gpetit I've merged the raster branch with the last h2 update. I have to write documentation and then create a pull request to h2 database.
The branch is here https://github.com/nicolas-f/h2database/tree/georaster_patch
Off db raster is still not supported yet. But band metadata can already store the path of the external image.
Add a unit test ? SELECT FILE_WRITE(ST_IMAGEFROMRASTER(data, 'png'), '/tmp/test.png') FROM test @nicolas-f