# solve_theta_from_spiral_length: Get theta from given spiral lengths In spiralize: Visualize Data on Spirals

## Description

Get theta from given spiral lengths

## Usage

 `1` ```solve_theta_from_spiral_length(len, interval = NULL, offset = 0) ```

## Arguments

 `len` A vector of spiral lengths. `interval` Interval to search for the solution. `offset` Offset of the spiral. In the general form: `r = a + r*theta`, offset is the value of `a`.

## Details

The length of the spiral has a complicated form, see https://downloads.imagej.net/fiji/snapshots/arc_length.pdf . Let's say the form is `l = f(theta)`, `solve_theta_from_spiral_length` tries to find theta by a known `l`. It uses `uniroot` to search solutions.

The theta value.

## Examples

 ```1 2 3 4 5``` ```spiral_initialize() s = current_spiral() theta = pi*seq(2, 3, length = 10) len = s\$spiral_length(theta) solve_theta_from_spiral_length(len) # should be very similar as theta ```

spiralize documentation built on Feb. 6, 2022, 1:06 a.m.