#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <netcdf.h>

Classes
struct	mapdata
	Stores a submap of the netcdf GRD data. More...

struct	mapsrc
	Stores info needed for accessing GMT GRD file. More...

struct	mapbounds
	Stores info about the boundaries of a GMT GRD file. This information can be used to determine if a location is within the bounds of an existing NetCDF GRD file. More...

Macros
#define	NAN 0

#define	MAPIO_DEBUG 0
	If not equal to zero then debug output will be printed. More...

#define	MAPIO_OK 1

#define	MAPIO_READERROR 2

#define	MAPIO_OUTOFMEMORY 4

#define	MAPSRC_IS_EMPTY 0

#define	MAPSRC_IS_FILLED 1

#define	MAPSRC_FILL_FAILURE 2

#define	MAPDATA_IS_EMPTY 0

#define	MAPDATA_IS_FILLED 1

#define	MAPDATA_FILL_FAILURE 2

#define	MAPBOUNDS_OK 0

#define	MAPBOUNDS_OUT_OF_BOUNDS 1

#define	MAPBOUNDS_NEAR_EDGE 2

Functions
int	check_error (int status, struct mapsrc *src)

void	mapsrc_fill (const char file, struct mapsrc src)
	Opens a GMT GRD file and read coordinate variables. More...

void	mapsrc_free (struct mapsrc *src)
	Frees the memory used by a mapsrc structure. More...

float	mapsrc_find (struct mapsrc *src, double x, double y)
	Find a z value at a given point. More...

struct mapsrc *	mapsrc_init (void)
	Initializes a mapsrc structure. More...

char *	mapsrc_tostring (struct mapsrc *src)
	create a string of a mapsrc structure More...

int	mapdata_fill (struct mapsrc src, struct mapdata data, double x, double y, double xwidth, double ywidth)
	Read a submap from a netcdf UTM GRD file into a mapdata structure. More...

void	mapdata_free (struct mapdata *data, int free_all)
	Free's the memory held by a mapdata structure. More...

char *	mapdata_tostring (struct mapdata *data)
	create a string of a mapdata structure More...

int	nearest (double key, const double *base, size_t nmemb)
	Find the index of the nearest value. More...

void	z_print (const float *z, int rows, int columns)

float	getZ (const float *z, int row, int column, int columns)

int	mapdata_check (struct mapdata data, struct mapsrc src, double xcenter, double ycenter, double xwidth, double ywidth)
	Returns a code indicating the status of the mapdata. More...

struct mapbounds *	mapbounds_init ()
	Create a mapbounds struct. More...

int	mapbounds_fill1 (struct mapsrc src, struct mapbounds bounds)
	Fills a mapbounds structure from a mapsrc object. More...

int	mapbounds_fill2 (const char file, struct mapbounds bounds)
	Fill in a mapbounds structure from a netcdf file. More...

char *	mapbounds_tostring (struct mapbounds *bounds)
	Return a string representation of a mapbounds struct. More...

int	mapbounds_contains (struct mapbounds *bounds, const double x, const double y)

int	mapdata_checksize (struct mapbounds bounds, struct mapdata data, const double xwidth, const double ywidth)

Macro Definition Documentation

#define MAPBOUNDS_NEAR_EDGE 2

#define MAPBOUNDS_OK 0

#define MAPBOUNDS_OUT_OF_BOUNDS 1

#define MAPDATA_FILL_FAILURE 2

#define MAPDATA_IS_EMPTY 0

#define MAPDATA_IS_FILLED 1

#define MAPIO_DEBUG 0

If not equal to zero then debug output will be printed.

Author: Copyright 2007 MBARI. All rights reserved.

Date: 2007-09-11

MAPIO is currently written to read a netCDF file (GMT version 2 GRD file) in UTM coordinates. (Generated with the -G3 flag in MBSsystem).

Here's an example CDL for the GMT version 2 netcdf grids we'll be working with:

 netcdf canyonDataUTMG3 {
 dimensions:
 x = 1022 ;
 y = 879 ;
 variables:
 double x(x) ;
 x:long_name = "Easting (meters)" ;
 x:actual_range = 597413.876506377, 598435.621004263 ;
 double y(y) ;
 y:long_name = "Northing (meters)" ;
 y:actual_range = 4071749.4760972, 4072627.48862688 ;
 float z(y, x) ;
 z:long_name = "Depth (m)" ;
 z:_FillValue = nanf ;
 z:actual_range = 374.4248f, 536.1101f ;

global attributes:
 :Conventions = "COARDS" ;
 :title = "Bathymetry Grid" ;
 :description = "\n",
 "\tProjection: UTM10N\n",
 "\tGrid created by mbgrid\n",
 "\tMB-system Version 5.1.0\n",
 "\tRun by <root> on <JacksonHole.stanford.edu> at <Thu Aug 30 00:44:23 2007>" ;
 :node_offset = 0 ;
 }

For this code, the projection is assumed to be UTM. We are ignoring the zone; you'll have to be smart enough to make sure all coordinates are within the same zone as the GRD file you are using.

#define MAPIO_OK 1

#define MAPIO_OUTOFMEMORY 4

#define MAPIO_READERROR 2

#define MAPSRC_FILL_FAILURE 2

#define MAPSRC_IS_EMPTY 0

#define MAPSRC_IS_FILLED 1

#define NAN 0

Function Documentation

int check_error	(	int	status,
		struct mapsrc *	src
	)

float getZ	(	const float *	z,
		int	row,
		int	column,
		int	columns
	)

int mapbounds_contains	(	struct mapbounds *	bounds,
		const double	x,
		const double	y
	)

int mapbounds_fill1	(	struct mapsrc *	src,
		struct mapbounds *	bounds
	)

Fills a mapbounds structure from a mapsrc object.

function: mapbounds_fill1

Fills in a mapbounds structure based on info in the src stucture

Parameters

src	The mapsrc data structure
bounds	The mapbounds data structure to populate

Returns: TODO...return a meaninful error code

int mapbounds_fill2	(	const char *	file,
		struct mapbounds *	bounds
	)

Fill in a mapbounds structure from a netcdf file.

function: mapbounds_fill2

Fills in a maounds structure based on data in the netcdf file

struct mapbounds* mapbounds_init ( )

Create a mapbounds struct.

function: mapbounds_init

Allocates memory for a mapbounds struct as sets all values to 0. The structure's memory will need to be freed when done with the structure.

Returns: A mapbounds structure

char* mapbounds_tostring ( struct mapbounds * bounds )

Return a string representation of a mapbounds struct.

function: mapbounds_tostring

String rep of a mapbounds struct

Parameters

bounds A mapbounds struct

Returns: A char*. Don't forget to free it when you're done with it

int mapdata_check	(	struct mapdata *	data,
		struct mapsrc *	src,
		double	xcenter,
		double	ycenter,
		double	xwidth,
		double	ywidth
	)

Returns a code indicating the status of the mapdata.

function: mapdata_check

TODO

Parameters

data	THe mapdata structure

Returns: An integer indicating the status of the data structure

int mapdata_checksize	(	struct mapbounds *	bounds,
		struct mapdata *	data,
		const double	xwidth,
		const double	ywidth
	)

int mapdata_fill	(	struct mapsrc *	src,
		struct mapdata *	data,
		double	x,
		double	y,
		double	xwidth,
		double	ywidth
	)

Read a submap from a netcdf UTM GRD file into a mapdata structure.

function: mapdata_fill

Reads in a rectangular block of bathymetry data from a file (defined by src). The size of the rectangle is based on the params but will NOT be exaclty as specified by xwidth and ywidth.

Parameters

src	The mapsrc structure definining where we are reading data from
data	A mapdata structure for storing the submap
x	The easting position of the vehicle. In the same UTM coordinate system as the src map.
y	The northing position of the vehicle. In the same UTM coordinate system as the src map.
xwidth	The width of the submap in meters to retrive.
ywidth	The width of the submap in meters to retrieve

Returns: An integer code of MAPBOUNDS_OK if all is OK, MAPBOUNDS_OUT_OF_BOUNDS if the x or y coordinate is outside the boundaries fo the map reference by src, or MAPBOUNDS_NEAR_EDGE if you x,y position is near the edge (resulting in a truncated submap)

void mapdata_free	(	struct mapdata *	data,
		int	free_all
	)

Free's the memory held by a mapdata structure.

function: mapdata_free

Parameters

data	The mapdata structure who's memory we want to free
free_all	If equal to 0 then the structure itself will not be freed, only the internal pointers. All structure values will be set to 0. if not equal to 1 then the data structure's memory will be release.

char* mapdata_tostring ( struct mapdata * data )

create a string of a mapdata structure

function: mapdata_tostring

Parameters

data	The mapdata structure

Returns: A string. Don't forget to free it when you're done.

void mapsrc_fill	(	const char *	file,
		struct mapsrc *	src
	)

Opens a GMT GRD file and read coordinate variables.

function: mapsrc_fill

Opens a GMT version 2 GRD file (netcdf). It stores the needed information, such as ids to the netcdf file, variables, and the data for the x and y coordinate variables. Note that 'struct mapsrc' contains references to arrays which must be released. If an error occurs on fill a flag will be set in the mapsrc.status field.

Parameters

file	The path of the file to read.
src	The mapsrc structure for storing the information about the netcdf data file.

float mapsrc_find	(	struct mapsrc *	src,
		double	x,
		double	y
	)

Find a z value at a given point.

function: mapsrc_find

Find a z-value in a map at a given x, y location

Parameters

src	The mapsrc structure pointing to the map you want to read
x	The x coordinate in meters UTM (use same zone as netCDF file).
y	The y coordinate in meters UTM (use same zone as netCDF file).

Returns: The z value in meters of the point nearest to the x, y location NAN is returned if the x,y coordinate falls outside the boundaries of the map.

void mapsrc_free ( struct mapsrc * src )

Frees the memory used by a mapsrc structure.

function: mapsrc_free

A mapsrc structure references to arrays. This function will free those arrays as well as the parent structure.

Parameters

src	Is the mapsrc structure to be freed

struct mapsrc* mapsrc_init ( void )

Initializes a mapsrc structure.

function: mapsrc_init

Allocates memory for a mapsrc structure and sets the status flags. You will need to call 'mapsrc_free' on the structure to release it's memory when you are finished with it.

Returns: A mapsrc structure.

char* mapsrc_tostring ( struct mapsrc * src )

create a string of a mapsrc structure

function: mapsrc_tostring

Parameters

src	The mapsrc structure

Returns: A string. Don't forget to free it when you're done.

int nearest	(	double	key,
		const double *	base,
		size_t	nmemb
	)

Find the index of the nearest value.

function: nearest

Finds the index of the nearest value in a double array to a key value. this is a naive implementation but should get us going.

Parameters

key	The key value
base	The double array that you're searcng to find the nearest value in. This implementation of nearest assumes the arrays are sorted ascending.
nmemb	The number of elements in the base array

void z_print	(	const float *	z,
		int	rows,
		int	columns
	)

Classes

Macros

Functions

Macro Definition Documentation

Function Documentation