rio calc

A raster data calculator

Evaluates an expression using input datasets and writes the result to a new dataset.

Command syntax is lisp-like. An expression consists of an operator or function name and one or more strings, numbers, or expressions enclosed in parentheses. Functions include read (gets a raster array) and asarray (makes a 3-D array from 2-D arrays).

* (read i) evaluates to the i-th input dataset (a 3-D array).

* (read i j) evaluates to the j-th band of the i-th dataset (a

2-D array).

* (read i j ‘float64’) casts the array to, e.g. float64. This

is critical if calculations will produces values that exceed

the limits of the dataset’s natural data type.

* (take foo j) evaluates to the j-th band of a dataset named foo

(see help on the –name option above).

* Standard numpy array operators (+, -, *, /) are available.

* When the final result is a list of arrays, a multiple band

output file is written.

* When the final result is a single array, a single band output

file is written.

Example:

$ rio calc “(+ 2 (* 0.95 (read 1)))” tests/data/RGB.byte.tif

> /tmp/out.tif

The command above produces a 3-band GeoTIFF with all values scaled by 0.95 and incremented by 2.

$ rio calc “(asarray (+ 125 (read 1)) (read 1) (read 1))”

> tests/data/shade.tif /tmp/out.tif

The command above produces a 3-band RGB GeoTIFF, with red levels incremented by 125, from the single-band input.

The maximum amount of memory used to perform caculations defaults to 64 MB. This number can be increased to improve speed of calculation.

rio calc [OPTIONS] COMMAND INPUTS... OUTPUT

Options

-o, --output <output>: Path to output file (optional alternative to a positional arg).

-f, --format, --driver <driver>: Output format driver.

--name <name>: Specify an input file with a unique short (alphas only) name for use in commands like “a=tests/data/RGB.byte.tif”.

-t, --dtype <dtype>

Output data type.

Options:: ubyte | uint8 | uint16 | int16 | uint32 | int32 | float32 | float64

--masked, --not-masked: Evaluate expressions using masked arrays (the default) or ordinary numpy arrays.

--overwrite: Always overwrite an existing output file.

--mem-limit <mem_limit>: Limit on memory used to perform calculations, in MB.

--co, --profile <NAME=VALUE>: Driver specific creation options. See the documentation for the selected output driver for more information.

Arguments

COMMAND: Required argument

INPUTS... OUTPUT: Required argument(s)