h3ToParent

Functions
EXTENSION_NOINLINE H3Index H3_EXPORT()	h3ToParent (H3Index h, int parentRes)
	returns the parent (or grandparent, etc) hexagon of the given hexagon More...

Detailed Description

Functions for h3ToParent

Function Documentation

EXTENSION_NOINLINE H3Index H3_EXPORT() h3ToParent	(	H3Index	h,
		int	parentRes
	)

returns the parent (or grandparent, etc) hexagon of the given hexagon

Returns the H3 resolution of an H3 index.

Parameters

h	The H3 index.

Returns

The resolution of the H3 index argument. Returns the H3 base cell "number" of an H3 cell (hexagon or pentagon).

Note: Technically works on H3 edges, but will return base cell of the origin cell.

Parameters

h	The H3 cell.

Returns

The base cell "number" of the H3 cell argument. Converts a string representation of an H3 index into an H3 index.

Parameters

str	The string representation of an H3 index.

Returns

The H3 index corresponding to the string argument, or H3_NULL if invalid. Converts an H3 index into a string representation.

Parameters

h	The H3 index to convert.
str	The string representation of the H3 index.
sz	Size of the buffer str Returns whether or not an H3 index is a valid cell (hexagon or pentagon).
h	The H3 index to validate.

Returns

1 if the H3 index if valid, and 0 if it is not. Initializes an H3 index.

Parameters

hp	The H3 index to initialize.
res	The H3 resolution to initialize the index to.
baseCell	The H3 base cell to initialize the index to.
initDigit	The H3 digit (0-7) to initialize all of the index digits to. h3ToParent produces the parent index for a given H3 index
h	H3Index to find parent of
parentRes	The resolution to switch to (parent, grandparent, etc)

Returns

H3Index of the parent, or H3_NULL if you actually asked for a child

Definition at line 144 of file h3Index.hpp.

References H3_DIGIT_MASK, H3_GET_RESOLUTION, H3_NULL, H3_SET_INDEX_DIGIT, H3_SET_RESOLUTION, H3Index, and MAX_H3_RES.

                                                                           {
  int childRes = H3_GET_RESOLUTION(h);
  if (parentRes > childRes) {
    return H3_NULL;
  } else if (parentRes == childRes) {
    return h;
  } else if (parentRes < 0 || parentRes > MAX_H3_RES) {
    return H3_NULL;
  }
  H3Index parentH = H3_SET_RESOLUTION(h, parentRes);
  for (int i = parentRes + 1; i <= childRes; i++) {
    H3_SET_INDEX_DIGIT(parentH, i, H3_DIGIT_MASK);
  }
  return parentH;
}