An Introduction to JPEG 2000 and GML for Geospatial imaging
Part one of this workshop will introduce the JPEG 2000 image compression system. We will cover the basics of image compression, the features that JPEG 2000 offers, and the new imaging workflows it enables. Emphasis will be on describing the breadth of the system, at the expense of details about how the system is implemented. Part two of this talk is will describe how GML can extend a raw image to provide an rich geospatial description the image and of the geographic features captured by the image. In particular, we will detail the structure and the components of a GML package that can be bundled in a JP2 file to provide image metadata for JPEG 2000.
Audience: Developers, managers, etc, wishing to find out more about the new JPEG standard and its relationship to GML. Basic familiarity with (raster) imaging and compression is assumed for part 1 and a basic familiarity of XML is assumed for part 2. No mathematical background is required.
Length: Part one: 2 hours. Part two: 1 hour.
Materials: Hardcopy of slides, CD with slides plus possibly GeoExpress 4.1 demo app and plug-in viewer.
Demos: There might be some live demos, e.g. of encoding trade-offs and image quality. Possible tools used would be GeoExpress, the viewer, the JP2 Photoshop plug-in, and the Kakadu tools. There will be no "hands-on" work in this presentation.
Course Content
Part 1 (2 hours):
- Intro
- Historical perspective
- Imaging basics
- Terminology, etc.
- Compression technology backgrounder
- Multires
- Arithmetic compression
- Color spaces and transforms
- Image control via the "quality / resolution / spatial extent" dimensions
- jp2 compression issues
- Tiles, precincts, etc, and why it matters
- Possible actual perf data (memory, speed)
- The jp2 file format
- Boxes, codestreams, user boxes
- JPIP
- What it is, why it matters
- Harken back to encoding trade-offs
- Other advanced topics
- jpx, mixed content support, motion jpeg, etc
- GIS issues
- Tile positioning and resolutions
- GeoJP2 metadata
- Vendor support
- Q&A
- GML
- Why GML? Problem domain, creating new opportunities.
- History of GML.
- Application of GML to imaging.
- GML Model
- Feature model
- Coverage model
- Geometry model
- CRS model
- Default styling
- Other models (topology, temporal, units)
- GML feature relationships geolinks
- GML Package inside JP2
- Schema definitions
- Coverage definition (instance)
- CRS dictionary
- Units of Measure dictionary
- Metadata
- Annotations
- Embedded features
- Designing and building GML schemas for image metadata
- GML patterns
- GML schema encoding rules
- Map styling - how to make maps from GML data
- Q&A