DESCRIPTION

g.cloud is a module to connect a personal GRASS GIS session to a remote GRASS GIS installation on a much faster cluster facility (high performance computing system). It currently only supports the Grid Engine system. The general aim is to offer the possibility to a user to perform high speed calculations, which are hard to compute on a personal computer by connecting to an external, powerful server or cloud computing system.

The g.cloud environment consists of a Python module. It checks if all program requirements are fullfilled on both the client and the server side. If everything is ok, it connects the current session to the cloud server; it transfers the user and other required scripts as well as the GRASS data to the server and eventually executes the remote GRASS GIS job. Subsequently, it transfers back the resulting maps and data and cleans up the server session.

For a job execution, the script requirements are two: on the client-side the user prepared GRASS GIS script which performs the calculations and on the server-side the qsub control script for Grid Engine to launch the GRASS GIS script job.

NOTES

It is highly recommended to use "ssh-add" in order to avoid the authentication to the cluster via password file.

EXAMPLE

North Carolina example, calculation of texture maps: 

g.cloud config=$HOME/.gc_loginfile.txt server=giscluster \
  grass_script=$HOME/g.cloud/test/test_onevariable_raster.sh \
  qsub_script=$HOME/g.cloud/test/launch_SGE_grassjob.sh \
  variables="{'TEXTURE' : ['asm','corr','entr','se','var']}" \
  raster=lsat7_2002_40

North Carolina example, calculation of daily sun radiation: 

g.cloud config=$HOME/.gc_loginfile.txt server=giscluster \
  grass_script=$HOME/g.cloud/test/test_onevariable_sun.sh \
  qsub_script=$HOME/test/launch_SGE_grassjob.sh \
  variables="{'DOY' : [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 230, 231, 232, 233, 234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, 246, 247, 248, 249, 250, 251, 252, 253, 254, 255, 256, 257, 258, 259, 260, 261, 262, 263, 264, 265, 266, 267, 268, 269, 270, 271, 272, 273, 274, 275, 276, 277, 278, 279, 280, 281, 282, 283, 284, 285, 286, 287, 288, 289, 290, 291, 292, 293, 294, 295, 296, 297, 298, 299, 300, 301, 302, 303, 304, 305, 306, 307, 308, 309, 310, 311, 312, 313, 314, 315, 316, 317, 318, 319, 320, 321, 322, 323, 324, 325]}" \
  raster=elevation

REQUIREMENTS

The software requirements are GRASS GIS 7 and ssh/scp on the client side; while on the server side the Grid Engine software or compatible software needs to be present to launch the GRASS jobs. Furthermore, python-pexpect is required to be installed on the client system.

REFERENCES

FOSS4G 2011 presentation

SEE ALSO

Parallel GRASS jobs from GRASS User Wiki

AUTHORS

Luca Delucchi, Markus Neteler, Fondazione Edmund Mach, Research and Innovation Centre, Department of Biodiversity and Molecular Ecology, GIS and Remote Sensing Unit

Last changed: $Date$