4.8 Processing and Analyzing GeoRaster Objects

You can perform a variety of raster and image processing operations on GeoRaster data, including changing the internal raster storage format, subsetting (cropping), scaling, rotating, masking, stretching, filtering, dodging, reprojecting (from one coordinate system to another), rectifying, orthorectifying, warping, mosaicking, appending, and generating pyramids. GeoRaster also supports virtual mosaic. Some relevant subprograms are SDO_GEOR.changeFormatCopy, SDO_GEOR.subset, SDO_GEOR.reproject, SDO_GEOR.rectify, SDO_GEOR.generatePyramid, SDO_GEOR.deletePyramid, SDO_GEOR.scaleCopy, SDO_GEOR.mergeLayers, SDO_GEOR_AGGR.mosaicSubset, SDO_GEOR_AGGR.getMosaicSubset, and SDO_GEOR_AGGR.append. For detailed descriptions, see Image Processing and Virtual Mosaic, SDO_GEOR Package Reference, and SDO_GEOR_AGGR Package Reference.

For raster cell value-based algebraic operations and cartographic modeling and analysis, GeoRaster supports a raster algebra language (PL/SQL and Algebraic Expressions) and related raster operations, including conditional queries (SDO_GEOR_RA.findCells), cell value-based updates or edits (SDO_GEOR_RA.rasterUpdate), logical and mathematical operations (SDO_GEOR_RA.rasterMathOp), and image and raster segmentation (SDO_GEOR_RA.classify). The SDO_GEOR.generateStatistics function supports polygon-based statistics and histogram generation. The following on-the-fly functions support interactive statistical analysis of a GeoRaster object or its layers: SDO_GEOR.generateStatisticsMax, SDO_GEOR.generateStatisticsMean, SDO_GEOR.generateStatisticsMedian, SDO_GEOR.generateStatisticsMin, SDO_GEOR.generateStatisticsMode, and SDO_GEOR.generateStatisticsSTD. For detailed descriptions, see Raster Algebra and Analytics and SDO_GEOR_RA Package Reference.

See also the GeoRaster PL/SQL demo files, described in GeoRaster PL/SQL and Java Demo Files, for examples and explanatory comments.