Package org.libtiff.jai.codec

Class XTIFFExt

  • public class XTIFFExt
extends XTIFF

    • Field Detail

      • GDAL_NODATA

        public static final int GDAL_NODATA
        Name GDAL_NODATA Type ASCII Count N Description Used by the GDAL library, contains an ASCII encoded nodata or background pixel value. In the geospatial image processing field especially (and in other fields) it is common to use a special pixel value to mark geospatial areas for which no information is available. This is often called a "nodata" or "background" value. Applications often treat these pixels as transparent and they are often not included in spatial statistics for the image. Non-geospatial applications might still use the nodata value to track a special value that should be treated as transparent since currently TIFF palettes don't include an alpha value. The GDAL_NODATA tag is intended to keep track of what pixel value is being used for this background nodata value. It is ASCII encoded so that if the pixel value 255 was to be treated as nodata, then the tag would have the value "255". If this tag is absent there is assume to be no nodata value in effect for the image. If the image has more than one sample it is assumed that all samples have the same nodata value. This tag is currently only supported by the GDAL library.
        See Also:
        Constant Field Values

      • GDAL_METADATA

        public static final int GDAL_METADATA
        Name GDAL_METADATA Type ASCII Count N Description Used by the GDAL library, holds an XML list of name=value 'metadata' values about the image as a whole, and about specific samples. Contains an XML fragment that looks like this example: BV02021.CA NASA-FAO 13, ARTEMIS NEWNASA Meters (elevation) 0 0.003 The names are the name of a metadata keyword, and the text contents of the Item are it's value. Normal XML escaping applies. The GDALMetadata tag may have zero or more Item sub-elements. Generally speaking the item names should be well behaved tokens (alpha-numeric + underscores) though that isn't strictly enforced. Also, normally the names are assumed to be unique. The "sample" attribute on an Item can be used to indicate a metadata item that applies only to one sample in a multi-sample TIFF image. Sample numbering starts from 0. The "role" attribute can be used to identify a specific semantic with a metadata item. GDAL has several specific pieces of metadata with particular interpretations and these are identified with role attributes. At a future date some of these specific roles may be documented here. This is an unregistered tag used only by the GDAL library and applications built on it to hold Metadata about geospatial datasets.
        See Also:
        Constant Field Values

      • ModelPixelScaleTag

        public static final int ModelPixelScaleTag
        Name ModelPixelScaleTag Type DOUBLE Count 3 Description Used in interchangeable GeoTIFF files. This tag is optionally provided for defining exact affine transformations between raster and model space. Baseline GeoTIFF files may use this tag or ModelTransformationTag, but shall never use both within the same TIFF image directory. This tag may be used to specify the size of raster pixel spacing in the model space units, when the raster space can be embedded in the model space coordinate system without rotation, and consists of the following 3 values: ModelPixelScaleTag = (ScaleX, ScaleY, ScaleZ) where ScaleX and ScaleY give the horizontal and vertical spacing of raster pixels. The ScaleZ is primarily used to map the pixel value of a digital elevation model into the correct Z-scale, and so for most other purposes this value should be zero (since most model spaces are 2-D, with Z=0).
        See Also:
        Constant Field Values

      • ModelTiepointTag

        public static final int ModelTiepointTag
        Name ModelTiepointTag Type DOUBLE Count N = 6*K, with K = number of tiepoints Description Originally part of Intergraph's GeoTIFF tags, but now used in interchangeable GeoTIFF files. This tag is also known as 'GeoreferenceTag'. This tag stores raster->model tiepoint pairs in the order ModelTiepointTag = (...,I,J,K, X,Y,Z...) where (I,J,K) is the point at location (I,J) in raster space with pixel-value K, and (X,Y,Z) is a vector in model space. In most cases the model space is only two-dimensional, in which case both K and Z should be set to zero; this third dimension is provided in anticipation of future support for 3D digital elevation models and vertical coordinate systems.
        See Also:
        Constant Field Values

      • ModelTransformationTag

        public static final int ModelTransformationTag
        Name ModelTransformationTag Type DOUBLE Count N = 16 Description Used in interchangeable GeoTIFF files. This tag is optionally provided for defining exact affine transformations between raster and model space. Baseline GeoTIFF files may use this tag or ModelPixelScaleTag, but shall never use both within the same TIFF image directory. This tag may be used to specify the transformation matrix between the raster space (and its dependent pixel-value space) and the (possibly 3D) model space.
        See Also:
        Constant Field Values

      • GeoKeyDirectoryTag

        public static final int GeoKeyDirectoryTag
        Name GeoKeyDirectoryTag Type SHORT Count N >= 4 Description Used in interchangeable GeoTIFF files. This tag is also know as 'ProjectionInfoTag' and 'CoordSystemInfoTag' This tag may be used to store the GeoKey Directory, which defines and references the "GeoKeys".
        See Also:
        Constant Field Values

      • GeoDoubleParamsTag

        public static final int GeoDoubleParamsTag
        Name GeoDoubleParamsTag Type DOUBLE Count N Description Used in interchangeable GeoTIFF files. This tag is used to store all of the DOUBLE valued GeoKeys, referenced by the GeoKeyDirectoryTag. The meaning of any value of this double array is determined from the GeoKeyDirectoryTag reference pointing to it. FLOAT values should first be converted to DOUBLE and stored here.
        See Also:
        Constant Field Values

      • GeoAsciiParamsTag

        public static final int GeoAsciiParamsTag
        Name GeoAsciiParamsTag Type ASCII Count N Description Used in interchangeable GeoTIFF files. This tag is used to store all of the ASCII valued GeoKeys, referenced by the GeoKeyDirectoryTag. Since keys use offsets into tags, any special comments may be placed at the beginning of this tag. For the most part, the only keys that are ASCII valued are "Citation" keys, giving documentation and references for obscure projections, datums, etc.
        See Also:
        Constant Field Values

    • Constructor Detail

      • XTIFFExt

        public XTIFFExt()