org.geotools.gce.grassraster.package-info Maven / Gradle / Ivy
/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2019, Open Source Geospatial Foundation (OSGeo)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*/
/**
*
*
* GRASS input/output drivers
*
* In this package the I/O drivers for reading and writing GRASS raster maps are placed.
*
*
To better understand the code a good overview should be taken on the GRASS
* database-Location-Mapset structure, of which a short introduction is given below.
*
*
File structure of GRASS Location
*
* A GRASS raster map consists of several files in several subdirectories in a mapset, organized as
* follows:
*
*
* - cellhd/: map header including projection code, coordinates representing the spatial
* extent of the raster map, number of rows and columns, resolution, and information about map
* compression;
*
- cell/, fcell/ or grid3/: generic matrix of values in a compressed, portable format
* which depends on the raster data type (integer, floating point or 3D grid);
*
- hist/: history file which contains metadata such as the data source, the command
* that was used to generate the raster map, or other information provided by the user;
*
- cats/: optional category file which contains text or numeric labels assigned to the
* raster map categories;
*
- colr/: optional color table;
*
- cell_misc/: optional timestamp, range of values, quantization rules (for floating
* point maps) and null (no-data) files;
*
*
* Most important files and folders for now:
*
*
* - WIND - contains the active processing region and the resolution
*
- PROJ_INFO - contains the information about the projection
*
- PROJ_UNITS - contains the information about projection units used
*
- cell, fcell - contain the raster files
*
- vector - contain the vector data since GRASS 6
*
- sites_list - contain the sites type data, deprecated from GRASS 6 on, but maintained in
* JGrass
*
*
* The cell header file
*
* A typical grass map header looks like the following:
*
* proj: 1
* zone: 13
* north: 4928000
* south: 4914000
* east: 609000
* west: 590000
* cols: 950
* rows: 700
* e-w resol: 20
* n-s resol: 20
* format: 0
* compressed: 1
*
*
*
*
Reclassified files
*
* If the first line reports 'reclass' then this file is a reclassified file and the original data
* file is given by the following two lines:
*
* reclass
* name: soils
* mapset: PERMANENT
* #1 5 3 8 .... ....
*
*
* The color table file
*
* Colortables for GRASS 5 and greater are supported.
*
*
The format of the color file, which is located in location/mapset/colr/mapname is the
* following:
*
*
The first line is a % character and two numbers indicating the minimum and maximum data values
* which have colors. Note that in JGrass after the range values we add a third value for alpha
* support.
*
*
After the first line, the list of color rules appears, that can be of the following formats:
*
*
* value1:r:g:b value2:r:g:b interpolation of colors between the two values with
* the two colors
* value1:grey value2:grey
*
* value1:r:g:b assumption that it means that value1 == value2
* nv:r:g:b novalues could also have color with such a rule.
*
*/
package org.geotools.gce.grassraster;