pe_horizon_pcs_raster_generate

Returns the projected horizon for a projected coordinate system for use with raster data.

Usage syntax

PE_HORIZON pe_horizon_pcs_raster_generate(PE_PROJCS projcs);

Parameters
projcs A valid projected coordinate system object.
Description

Currently, this function only works with the Cube and Fuller projections.

A projected horizon defines the valid area of use for a particular projected coordinate system. The pe_horizon_pcs_raster_generate function returns a horizon in the projected coordinate system. One use might be to identify whether a user's click in a display is within the valid area of current projected coordinate system. The horizon structure is:

typedef struct pe_horizon_t {
int nump;
int kind;
int inclusive;
int replicate;
int size;
double *coord[2];
} *PE_HORIZON;

The nump argument is the number of parts in the horizon, while kind describes the shape type. The kind values are:

PE_HORIZON_RECT
PE_HORIZON_POLY
PE_HORIZON_LINE
PE_HORIZON_POINT

Inclusive can have a value of 1 or 0. If 1, the horizon is inclusive. if 0, the horizon is exclusive. Projected horizons are returned in the units of the projected coordinate system.

Size is the number of coordinates in the part while coord is a pointer to the array of coordinate values.

Returns

On success, a pointer to an array of horizons. On failure, a null pointer.

Examples

PE_PROJCS pcs1 = pe_factory_projcs(PE_PCS_WORLD_FULLER);
PE_HORIZON *pcs_horz = pe_horizon_pcs_raster_generate(pcs1);