Provides basic information about the GeoTIFF format IO.
this class is responsible for exposing the data and the Georeferencing metadata available to the Geotools library.
This package is going to be "evolutionary", rather than "revolutionary". As functionality is added to the package, this page will be updated. This page should be considered a current synopsis of the capabilities of the module.
GeoTiffFormatFactorySpiwill report itself unavailable if any of the following are unavailable:
Other classes are of course necessary to successfully read in the GeoTIFF image. As they typically come bundled with one or more of the above, they are assumed to be present if all of the above are present.
The ability of the GeoTiff module to interpret and accurately express the geographic information encoded in the GeoTIFF file relies strongly on it's ability to use the Geotools framework to construct a meaningful coordinate reference system (CRS) object. Geotools has a number of Authority Factories which take care of constructing CRS information given the code assigned to that CRS.
The central problem is that a complete CRS is composed of many smaller pieces (coordinate systems (CS), datums, and coordinate operations.) Each of these smaller peices is assigned a code for berevity. So when a GeoTIFF file is written, the coordinate information can either be a single code representing the entire CRS (if you're lucky), or a combination of each of the component codes. Reading a GeoTIFF involves the reverse process: looking up either a single code or a collection of the component codes and building up a CRS object from these components.
Geotools supports the looking up of EPSG codes in plugins. Therefore it is critical that the environment inside which the GeoTIFF plugin is running contain the appropriate epsg authority factory plugins. Unfortunately, the definition of "appropriate" varies according to the type of GeoTIFF file you are trying to read. If you know that your GeoTIFF file contains only codes for complete CRSes, then you can use an EPSG plugin which only looks up complete CRSes (e.g., epsg-wkt, the property file based EPSG authority factory.) If, however, you want to be able to handle more types of GeoTIFF files (perhaps you do not know where your GeoTIFF files are coming from), you must choose an EPSG authority factory which can lookup components of a CRS (e.g., epsg-access, the MS Access backed authority factory.)
In short, the exact means by which EPSG codes are turned into actual Java Objects is left up to the application writer. Ensure that the capabilities you have configured match the requirements imposed by the data you are trying to read.
The current iteration of the GeoTIFF plugin will read GeoTIFF files with the following restrictions:
The GeoTIFF plugin currently does not write GeoTIFF files. The current obstacles to writing a GeoTIFF file are:
GeoTiffIIOMetadataAdaptercannot modify the IIOMetadata object (e.g., it's read-only).
Key features of the package:
GeoTiffIIOMetadataAdapteris Copyright 2004 by Mike Gelbin and released under a liberal license as noted in that file.
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