I'm wondering does anyone have examples for extracting raster data from Oracle OrdImage format and creating a GeoTIFF using GDAL?
I see some info on extracting GeoRasters but not OrdImage.
Add a comment
|
1 Answer
The Ordimage type has been deprecated for several releases and was finally removed from release 19c onwards.
Ordimage is very different from Georaster. Georaster is designed to store and process geo-spatially referenced imagery as well as any geo-referenced grids: terrain models, weather and climate grids, statistical grids, etc.
Ordimage was design to store and manage photos: stock photos, medical imaging, … Some of those photos could be aerial photographs, but the metadata maintained by Ordimage did not contain any georeferencing information as understood in the geospatial world (footprint, coordinate system, transformation parameters …) Also those images are rarely ortho-rectified. The metadata could however contain spatial coordinates if the camera that took it had the ability to capture and encode that in its the image-embedded metadata.
GDAL is composed of a core engine with a series of drivers/plugins to support the various file/data types. A plug-in exists for Oracle Georaster. None was ever developed for OrdImage, simply (I assume) because no one found it to be necessary.
If you need to extract images stored in Ordimage back to files you can do that using the export() procedure of the ORD_IMAGE PL/SQL package, but you will need to provide the additional georeferencing information to complement the image (world file, SRID). With this information you can use GDAL to convert the result into a GeoTiff structure that will be a valid raster.
