In an MRR, data is stored in one or more fields, each of which consists of one or more data bands. There are four fundamental field types – Image, Image Palette, Classified and Continuous. A field can contain the following data types:
- Image - An Image field contains a single band of color data. MRR supports a wide variety of color data types including single-component and multi-component types such as 24-bit Red Green Blue (RGB).
- Image Palette - An Image Palette field uses a restricted color palette. The color palette can store color in any supported color type, just like an Image field. The number of entries in the color palette is determined by the user and is virtually unlimited. The MRR contains an integer index band that stores the color index for every cell.
- Classified - A classified field has an integer index band that stores the class index for each cell. An MRR can store many classification tables of varying sizes. The classification table can contain any number of data channels of any supported data type including integer and floating point numeric, date-time, color, strings and Binary Large OBjects.
- Numeric (discrete) - A numeric field contains bit (1/2/4) or numeric (integer, float, complex, date time) data bands. The data value for a cell represents the average value of the measured quantity over the cell region.
- Numeric (continuous) - A continuous field contains one or more data bands of any supported data type. Typically these bands will contain integer or floating point data, complex numbers, date-time or color data. The data type of each band can be different and each band can have a unique validity mask identifying whether the band value is valid or invalid in each cell.
There is no restriction on how many fields can be stored in an MRR - nor on the type of the fields which are present. So it is possible, for example, to store both image data and numeric data within a single MRR file.
For example, the remote sensing platforms return multi-spectral data in multiple resolutions; generally an integer multiple or fraction of the primary resolution. To support this, every field in an MRR has its own cell-world-transform definition to allow users to set a unique cell size for each field, if desired.
Field-Band indexing
Most of the raster operations support one-based index, as a result, the index sequence for a field or band starts at ‘1’. Whereas the MapInfo Pro Raster .Net API uses zero-based index, so the index sequence for a field or band starts at ‘0’. There are some exceptions to this such as in a Calculator expression where starting index is ‘0’ for multi-field/multi-band files.