Martin Desruisseaux created SIS-307:
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Summary: Create the foundation of a module for remote sensing data
Key: SIS-307
URL: https://issues.apache.org/jira/browse/SIS-307
Project: Spatial Information Systems
Issue Type: New Feature
Components: Storage
Reporter: Martin Desruisseaux
Assignee: Martin Desruisseaux
This is a proposal for a [Google Summer of
Code|https://summerofcode.withgoogle.com/] (GSoC) project. The Apache SIS
library needs a module for efficient handling of large _n_-dimensional remote
sensing data. The module shall:
* Provide a common approach to the reading and writing of grid coverages
applicable to simple imagery as to multi-dimensional data structures.
* Allow operations that preserve the scientific meaning of data (e.g.
distinguish between measurements and missing values, why the value is missing,
estimation of accuracy).
* Be compliant with international standards, in particular (but not only)
_Schema for coverage geometry and functions_ (ISO 19123) and _Web Coverage
Services_ (WCS). The module should provide extensions to those standards only
for aspects that are not covered by an existing standard.
This module will be a redesign of coverage module that existed in previous
projects. In particular, the coverage module of the
[Geotk|http://www.geotoolkit.org] project will be used as a starting point.
However an important focus of this project is to fix known limitations of
previous projects, for example:
* Too strong reliance on {{javax.imageio}} API, which was designed for
two-dimensional images. That API is difficult to generalize to three- or
four-dimensional data accesses.
* Too strong reliance on {{javax.imageio.metadata}} API, which is basically a
XML document. Ordinary Java objects are more convenient to use and the ISO
19115 international standard can be a good model for those objects.
* Too strong restriction on the grid geometry (in previous projects, the
conversion from pixel coordinates to "real world" coordinates is restricted to
an affine transform).
* Only quadrilateral grid coverages were supported.
h3. Proof of concept
In order to ensure that the module is on the right track, a small application
(either a desktop application for browsing images or a simple web application
conforms to the WCS standard) will be created. This simple application will be
created in collaboration with volunteers of a space agency, and should be able
to:
* Read at least one image format of that space agency.
* Allow diffusion of those data in time range, sub-area, sub-sampling and
layers selected by the user.
* Allow searches in some metadata fields (to be selected according the needs of
the space agency).
h3. Non-goals
This GSoC project is not expected to create a fully functional coverage module
in 3 months. Performance is not a concern for this initial stage (in
particular, building index or storing information in a database is out of
scope), except that the application shall not load all data in memory: the
application should prove that it can work with only a small fraction of the
data in memory and load the remaining parts when needed.
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