# Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world.

##### transform

Transforms from one geometry to another geometry using a strategy.

###### Synopsis

```template<typename Geometry1, typename Geometry2>
bool transform(Geometry1 const & geometry1, Geometry2 & geometry2)```

###### Parameters

Type

Concept

Name

Description

Geometry1 const &

Any type fulfilling a Geometry Concept

geometry1

A model of the specified concept

Geometry2 &

Any type fulfilling a Geometry Concept

geometry2

A model of the specified concept

###### Returns

True if the transformation could be done

Either

`#include <boost/geometry.hpp>`

Or

`#include <boost/geometry/algorithms/transform.hpp>`

###### Conformance

The function transform is not defined by OGC.

###### Behavior

Case

Behavior

Transforms coordinates from degree to radian, or vice versa

Spherical / Cartesian (3D)

Transforms coordinates from spherical coordinates to X,Y,Z, or vice versa, on a unit sphere

Transforms coordinates from degree to radian, or vice versa. Third coordinate (radius) is untouched

Spherical (with radius) / Cartesian (3D)

Transforms coordinates from spherical coordinates to X,Y,Z, or vice versa, on a unit sphere. Third coordinate (radius) is taken into account

Linear

###### Example

Shows how points can be transformed using the default strategy

```#include <iostream>
#include <boost/geometry.hpp>

int main()
{
namespace bg = boost::geometry;

// Select a point near the pole (theta=5.0, phi=15.0)
bg::model::point<long double, 2, bg::cs::spherical<bg::degree> > p1(15.0, 5.0);

// Transform from degree to radian. Default strategy is automatically selected,
// it will convert from degree to radian
bg::model::point<long double, 2, bg::cs::spherical<bg::radian> > p2;
bg::transform(p1, p2);

// Transform from degree (lon-lat) to 3D (x,y,z). Default strategy is automatically selected,
// it will consider points on a unit sphere
bg::model::point<long double, 3, bg::cs::cartesian> p3;
bg::transform(p1, p3);

std::cout
<< "p1: " << bg::dsv(p1) << std::endl
<< "p2: " << bg::dsv(p2) << std::endl
<< "p3: " << bg::dsv(p3) << std::endl;

return 0;
}
```

Output:

```p1: (15, 5)
p2: (0.261799, 0.0872665)
p3: (0.084186, 0.0225576, 0.996195)
```