r.tilesetgrass - Online in the Cloud

PROGRAM:

NAME

r.tileset - Produces tilings of the source projection for use in the destination region
and projection.

KEYWORDS

raster, tiling

SYNOPSIS

r.tileset
r.tileset --help
r.tileset [-gw] [region=string] sourceproj=string [sourcescale=string]
[destproj=string] [destscale=string] [maxcols=integer] [maxrows=integer]
[overlap=integer] [separator=character] [--help] [--verbose] [--quiet] [--ui]

Flags:
-g
Produces shell script output

-w
Produces web map server query string output

--help
Print usage summary

--verbose
Verbose module output

--quiet
Quiet module output

--ui
Force launching GUI dialog

Parameters:
region=string
Name of region to use instead of current region for bounds and resolution

sourceproj=string [required]
Source projection

sourcescale=string
Conversion factor from units to meters in source projection
Default: 1

destproj=string
Destination projection, defaults to this location’s projection

destscale=string
Conversion factor from units to meters in source projection

maxcols=integer
Maximum number of columns for a tile in the source projection
Default: 1024

maxrows=integer
Maximum number of rows for a tile in the source projection
Default: 1024

overlap=integer
Number of cells tiles should overlap in each direction
Default: 0

separator=character
Field separator
Output field separator
Default: pipe

DESCRIPTION

r.tileset generates sets of tiles in another projection that cover a region in this
projection with adequate resolution. By default the current region and its resolution are
used, the bounds and resolution of another region can be used via the region option.

NOTES

r.tileset does not make "optimal" tilings (as few tiles of the largest size less than the
maximums). This means that from latitude longitude projection to an appropriate projection
for a region, in the degenerate case, it may create tiles demanding up to twice the
necessary information. Furthermore, generating a tiling near a divergant point of a source
projection, such as the poles of a cylindrical source projections, results in divergence
of the tile set.

Not generating "optimal" tilings may have another consequence; the aspect ratio of cells
in the destination region will not necessarily carry over to the source region and
generated tiles may have cells of strange aspect ratios. This might be a problem for some
map request services presenting data in an inappropriate projection or with strict
constraints on cell aspect ratio.

OUTPUT FORMAT

Each tile is listed on a separate line in the output. The lines are formatted as follows:

5|125|45|175|80|100
This is the default output format. It is the tile’s minimum x coordinate, minimum y
coordinate, maximum x coordinate, maximum y coordinate, width in cells, and height in
cells separated by the "|" character. The fields can be separated by a different
character by changing the fs option.

w=5;s=125;e=45;n=175;cols=80;rows=100;
This is output in a format convinent for setting variables in a shell script.

bbox=5,125,45,175&width=80&height=100
This is output in a format convinent for requesting data from some http services.

EXAMPLES

Generates tiles in latitude longitude that cover the current region, each tile will be
less than 1024 cells high and 2048 cells across. The bounds and sizes of tiles in the
output are separated by | (pipe):

r.tileset sourceproj=+init=epsg:4326 maxrows=1024 maxcols=2048
Generates tiles in latitude longitude projection that cover the named region "ne-rio". The
tiles will have 2 cells of overlap. The output format will be strings like the bbox
requests for WMS servers:

r.tileset sourceproj=+init=epsg:4326 overlap=2 -w region=ne-rio
Generates tiles in the projection of the location "IrishGrid". Each tile will be less than
300x400 cells in size, with 3 cells of overlap in the top and right sides of each tile.
The output is in a format where each line is in shell script style. The substitution
`g.proj -j location=IrishGrid` will only work in a unix style shell:

r.tileset sourceproj="`g.proj -j location=IrishGrid`" maxrows=400 maxcols=300 overlap=3 -g

KNOWN ISSUES

· r.tileset does not know about meridians that "wrap-around" in projections.

AUTHORS

Cedric Shock
Updated for GRASS 7 by Martin Landa, CTU in Prague, Czech Republic

Last changed: $Date: 2015-05-11 02:16:13 +0200 (Mon, 11 May 2015) $

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