Routines (alphabetical) > Routines: H > HDF Routines > HDF_GR_READIMAGE

# HDF_GR_READIMAGE

This function reads the subsample of the HDF GR raster image specified by the parameter ri_id into the variable data.

## Syntax

Result = HDF_GR_READIMAGE( ri_id, data [, EDGE=array] [, /INTERLACE] [, START=array] [, STRIDE=array] )

## Return Value

Returns SUCCEED (0) if successful or FAIL (-1) if otherwise.

## Arguments

### ri_id

Raster image identifier returned by HDF_GR_CREATE or HDF_GR_SELECT

### data

A named variable that will contain the image data.

## Keywords

### EDGE

Array specifying the number of values to be read along each dimension. The default is to read the entire specified image.

### INTERLACE

Set this keyword to force data to be returned in INTERLACE mode. The default is pixel-interlacing (0) other possible values are 1 (line) and 2 (component).

### START

Array specifying the starting location from where raster image data is read. Valid values of each element in the array are 0 to the size of the corresponding raster image dimension minus 1. The default is to read starting at the first pixel in each dimension (start = [0,0]).

### STRIDE

Array specifying the interval between the values that will be read along each dimension. The default is for contiguous reading along each dimension (stride = [1,1]).

Note: The correspondence between the elements in the array start and the array data dimensions in the HDF GR interface is different from that in the HDF SD interface. The array stride specifies the reading pattern along each dimension. For example, if one of the elements of the array stride is 1, then every element along the corresponding dimension of the array data will be read. If one of the elements of the array stride is 2, then every other element along the corresponding dimension of the array data will be read, and so on. The correspondence between elements of the array stride and the dimensions of the array data is the same as described above for the array start. Each element of the array edges specifies the number of data elements to be read along the corresponding dimension. The correspondence between the elements of the array edges and the dimensions of the array data is the same as described above for the array start.

## Version History

5.2 | Introduced