/*
* viking -- GPS Data and Topo Analyzer, Explorer, and Manager
*
* Copyright (C) 2003-2008, Evan Battaglia <gtoevan@gmx.net>
* Copyright (C) 2007, Quy Tonthat <qtonthat@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <stdio.h>
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#include <glib.h>
#ifdef HAVE_MATH_H
#include <math.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#include <zlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <glib/gstdio.h>
#include <glib/gi18n.h>
#include "dem.h"
#include "file.h"
#define DEM_BLOCK_SIZE 1024
#define GET_COLUMN(dem,n) ((VikDEMColumn *)g_ptr_array_index( (dem)->columns, (n) ))
static gboolean get_double_and_continue ( gchar **buffer, gdouble *tmp, gboolean warn )
{
gchar *endptr;
*tmp = g_strtod(*buffer, &endptr);
if ( endptr == NULL|| endptr == *buffer ) {
if ( warn )
g_warning(_("Invalid DEM"));
return FALSE;
}
*buffer=endptr;
return TRUE;
}
static gboolean get_int_and_continue ( gchar **buffer, gint *tmp, gboolean warn )
{
gchar *endptr;
*tmp = strtol(*buffer, &endptr, 10);
if ( endptr == NULL|| endptr == *buffer ) {
if ( warn )
g_warning(_("Invalid DEM"));
return FALSE;
}
*buffer=endptr;
return TRUE;
}
static gboolean dem_parse_header ( gchar *buffer, VikDEM *dem )
{
gdouble val;
gint int_val;
guint i;
gchar *tmp = buffer;
/* incomplete header */
if ( strlen(buffer) != 1024 )
return FALSE;
/* fix Fortran-style exponentiation 1.0D5 -> 1.0E5 */
while (*tmp) {
if ( *tmp=='D')
*tmp='E';
tmp++;
}
/* skip name */
buffer += 149;
/* "DEM level code, pattern code, palaimetric reference system code" -- skip */
get_int_and_continue(&buffer, &int_val, TRUE);
get_int_and_continue(&buffer, &int_val, TRUE);
get_int_and_continue(&buffer, &int_val, TRUE);
/* zone */
get_int_and_continue(&buffer, &int_val, TRUE);
dem->utm_zone = int_val;
/* TODO -- southern or northern hemisphere?! */
dem->utm_letter = 'N';
/* skip numbers 5-19 */
for ( i = 0; i < 15; i++ ) {
if ( ! get_double_and_continue(&buffer, &val, FALSE) ) {
g_warning (_("Invalid DEM header"));
return FALSE;
}
}
/* number 20 -- horizontal unit code (utm/ll) */
get_double_and_continue(&buffer, &val, TRUE);
dem->horiz_units = val;
get_double_and_continue(&buffer, &val, TRUE);
/* dem->orig_vert_units = val; now done below */
/* TODO: do this for real. these are only for 1:24k and 1:250k USGS */
if ( dem->horiz_units == VIK_DEM_HORIZ_UTM_METERS ) {
dem->east_scale = 10.0; /* meters */
dem->north_scale = 10.0;
dem->orig_vert_units = VIK_DEM_VERT_DECIMETERS;
} else {
dem->east_scale = 3.0; /* arcseconds */
dem->north_scale = 3.0;
dem->orig_vert_units = VIK_DEM_VERT_METERS;
}
/* skip next */
get_double_and_continue(&buffer, &val, TRUE);
/* now we get the four corner points. record the min and max. */
get_double_and_continue(&buffer, &val, TRUE);
dem->min_east = dem->max_east = val;
get_double_and_continue(&buffer, &val, TRUE);
dem->min_north = dem->max_north = val;
for ( i = 0; i < 3; i++ ) {
get_double_and_continue(&buffer, &val, TRUE);
if ( val < dem->min_east ) dem->min_east = val;
if ( val > dem->max_east ) dem->max_east = val;
get_double_and_continue(&buffer, &val, TRUE);
if ( val < dem->min_north ) dem->min_north = val;
if ( val > dem->max_north ) dem->max_north = val;
}
return TRUE;
}
static void dem_parse_block_as_cont ( gchar *buffer, VikDEM *dem, gint *cur_column, gint *cur_row )
{
gint tmp;
while ( *cur_row < GET_COLUMN(dem, *cur_column)->n_points ) {
if ( get_int_and_continue(&buffer, &tmp,FALSE) ) {
if ( dem->orig_vert_units == VIK_DEM_VERT_DECIMETERS )
GET_COLUMN(dem, *cur_column)->points[*cur_row] = (gint16) (tmp / 10);
else
GET_COLUMN(dem, *cur_column)->points[*cur_row] = (gint16) tmp;
} else
return;
(*cur_row)++;
}
*cur_row = -1; /* expecting new column */
}
static void dem_parse_block_as_header ( gchar *buffer, VikDEM *dem, gint *cur_column, gint *cur_row )
{
guint n_rows;
gint i;
gdouble east_west, south;
gdouble tmp;
/* 1 x n_rows 1 east_west south x x x DATA */
if ( (!get_double_and_continue(&buffer, &tmp, TRUE)) || tmp != 1 ) {
g_warning(_("Incorrect DEM Class B record: expected 1"));
return;
}
/* don't need this */
if ( !get_double_and_continue(&buffer, &tmp, TRUE ) ) return;
/* n_rows */
if ( !get_double_and_continue(&buffer, &tmp, TRUE ) )
return;
n_rows = (guint) tmp;
if ( (!get_double_and_continue(&buffer, &tmp, TRUE)) || tmp != 1 ) {
g_warning(_("Incorrect DEM Class B record: expected 1"));
return;
}
if ( !get_double_and_continue(&buffer, &east_west, TRUE) )
return;
if ( !get_double_and_continue(&buffer, &south, TRUE) )
return;
/* next three things we don't need */
if ( !get_double_and_continue(&buffer, &tmp, TRUE)) return;
if ( !get_double_and_continue(&buffer, &tmp, TRUE)) return;
if ( !get_double_and_continue(&buffer, &tmp, TRUE)) return;
dem->n_columns ++;
(*cur_column) ++;
/* empty spaces for things before that were skipped */
(*cur_row) = (south - dem->min_north) / dem->north_scale;
if ( south > dem->max_north || (*cur_row) < 0 )
(*cur_row) = 0;
n_rows += *cur_row;
g_ptr_array_add ( dem->columns, g_malloc(sizeof(VikDEMColumn)) );
GET_COLUMN(dem,*cur_column)->east_west = east_west;
GET_COLUMN(dem,*cur_column)->south = south;
GET_COLUMN(dem,*cur_column)->n_points = n_rows;
GET_COLUMN(dem,*cur_column)->points = g_malloc(sizeof(gint16)*n_rows);
/* no information for things before that */
for ( i = 0; i < (*cur_row); i++ )
GET_COLUMN(dem,*cur_column)->points[i] = VIK_DEM_INVALID_ELEVATION;
/* now just continue */
dem_parse_block_as_cont ( buffer, dem, cur_column, cur_row );
}
static void dem_parse_block ( gchar *buffer, VikDEM *dem, gint *cur_column, gint *cur_row )
{
/* if haven't read anything or have read all items in a columns and are expecting a new column */
if ( *cur_column == -1 || *cur_row == -1 ) {
dem_parse_block_as_header(buffer, dem, cur_column, cur_row);
} else {
dem_parse_block_as_cont(buffer, dem, cur_column, cur_row);
}
}
/* return size of unzip data or 0 if failed */
/* can be made generic to uncompress zip, gzip, bzip2 data */
static guint uncompress_data(void *uncompressed_buffer, guint uncompressed_size, void *compressed_data, guint compressed_size)
{
z_stream stream;
int err;
stream.next_in = compressed_data;
stream.avail_in = compressed_size;
stream.next_out = uncompressed_buffer;
stream.avail_out = uncompressed_size;
stream.zalloc = (alloc_func)0;
stream.zfree = (free_func)0;
stream.opaque = (voidpf)0;
/* negative windowBits to inflateInit2 means "no header" */
if ((err = inflateInit2(&stream, -MAX_WBITS)) != Z_OK) {
g_warning("%s(): inflateInit2 failed", __PRETTY_FUNCTION__);
return 0;
}
err = inflate(&stream, Z_FINISH);
if ((err != Z_OK) && (err != Z_STREAM_END) && stream.msg) {
g_warning("%s() inflate failed err=%d \"%s\"", __PRETTY_FUNCTION__, err, stream.msg == NULL ? "unknown" : stream.msg);
inflateEnd(&stream);
return 0;
}
inflateEnd(&stream);
return(stream.total_out);
}
static void *unzip_hgt_file(gchar *zip_file, gulong *unzip_size)
{
void *unzip_data = NULL;
gchar *zip_data;
struct _lfh {
guint32 sig;
guint16 extract_version;
guint16 flags;
guint16 comp_method;
guint16 time;
guint16 date;
guint32 crc_32;
guint32 compressed_size;
guint32 uncompressed_size;
guint16 filename_len;
guint16 extra_field_len;
} __attribute__ ((__packed__)) *local_file_header = NULL;
local_file_header = (struct _lfh *) zip_file;
if (local_file_header->sig != 0x04034b50) {
g_warning("%s(): wrong format", __PRETTY_FUNCTION__);
g_free(unzip_data);
goto end;
}
zip_data = zip_file + sizeof(struct _lfh) + local_file_header->filename_len + local_file_header->extra_field_len;
unzip_data = g_malloc(local_file_header->uncompressed_size);
gulong uncompressed_size = local_file_header->uncompressed_size;
if (!(*unzip_size = uncompress_data(unzip_data, uncompressed_size, zip_data, local_file_header->compressed_size))) {
g_free(unzip_data);
unzip_data = NULL;
goto end;
}
end:
return(unzip_data);
}
static VikDEM *vik_dem_read_srtm_hgt(const gchar *file_name, const gchar *basename, gboolean zip)
{
gint i, j;
VikDEM *dem;
off_t file_size;
gint16 *dem_mem = NULL;
gchar *dem_file = NULL;
const gint num_rows_3sec = 1201;
const gint num_rows_1sec = 3601;
gint num_rows;
GMappedFile *mf;
gint arcsec;
GError *error = NULL;
dem = g_malloc(sizeof(VikDEM));
dem->horiz_units = VIK_DEM_HORIZ_LL_ARCSECONDS;
dem->orig_vert_units = VIK_DEM_VERT_DECIMETERS;
/* TODO */
dem->min_north = atoi(basename+1) * 3600;
dem->min_east = atoi(basename+4) * 3600;
if ( basename[0] == 'S' )
dem->min_north = - dem->min_north;
if ( basename[3] == 'W' )
dem->min_east = - dem->min_east;
dem->max_north = 3600 + dem->min_north;
dem->max_east = 3600 + dem->min_east;
dem->columns = g_ptr_array_new();
dem->n_columns = 0;
if ((mf = g_mapped_file_new(file_name, FALSE, &error)) == NULL) {
g_error(_("Couldn't map file %s: %s"), file_name, error->message);
g_error_free(error);
g_free(dem);
return NULL;
}
file_size = g_mapped_file_get_length(mf);
dem_file = g_mapped_file_get_contents(mf);
if (zip) {
void *unzip_mem = NULL;
gulong ucsize;
if ((unzip_mem = unzip_hgt_file(dem_file, &ucsize)) == NULL) {
g_mapped_file_free(mf);
g_ptr_array_free(dem->columns, TRUE);
g_free(dem);
return NULL;
}
dem_mem = unzip_mem;
file_size = ucsize;
}
if (file_size == (num_rows_3sec * num_rows_3sec * sizeof(gint16)))
arcsec = 3;
else if (file_size == (num_rows_1sec * num_rows_1sec * sizeof(gint16)))
arcsec = 1;
else {
g_warning("%s(): file %s does not have right size", __PRETTY_FUNCTION__, basename);
g_mapped_file_free(mf);
g_free(dem);
return NULL;
}
num_rows = (arcsec == 3) ? num_rows_3sec : num_rows_1sec;
dem->east_scale = dem->north_scale = arcsec;
for ( i = 0; i < num_rows; i++ ) {
dem->n_columns++;
g_ptr_array_add ( dem->columns, g_malloc(sizeof(VikDEMColumn)) );
GET_COLUMN(dem,i)->east_west = dem->min_east + arcsec*i;
GET_COLUMN(dem,i)->south = dem->min_north;
GET_COLUMN(dem,i)->n_points = num_rows;
GET_COLUMN(dem,i)->points = g_malloc(sizeof(gint16)*num_rows);
}
int ent = 0;
for ( i = (num_rows - 1); i >= 0; i-- ) {
for ( j = 0; j < num_rows; j++ ) {
GET_COLUMN(dem,j)->points[i] = GINT16_FROM_BE(dem_mem[ent]);
ent++;
}
}
if (zip)
g_free(dem_mem);
g_mapped_file_free(mf);
return dem;
}
#define IS_SRTM_HGT(fn) (strlen((fn))==11 && (fn)[7]=='.' && (fn)[8]=='h' && (fn)[9]=='g' && (fn)[10]=='t' && ((fn)[0]=='N' || (fn)[0]=='S') && ((fn)[3]=='E' || (fn)[3]=='W'))
VikDEM *vik_dem_new_from_file(const gchar *file)
{
FILE *f=NULL;
VikDEM *rv;
gchar buffer[DEM_BLOCK_SIZE+1];
/* use to record state for dem_parse_block */
gint cur_column = -1;
gint cur_row = -1;
const gchar *basename = a_file_basename(file);
if ( g_access ( file, R_OK ) != 0 )
return NULL;
if ( (strlen(basename)==11 || ((strlen(basename) == 15) && (basename[11] == '.' && basename[12] == 'z' && basename[13] == 'i' && basename[14] == 'p'))) &&
basename[7]=='.' && basename[8]=='h' && basename[9]=='g' && basename[10]=='t' &&
(basename[0] == 'N' || basename[0] == 'S') && (basename[3] == 'E' || basename[3] =='W')) {
gboolean is_zip_file = (strlen(basename) == 15);
rv = vik_dem_read_srtm_hgt(file, basename, is_zip_file);
return(rv);
}
/* Create Structure */
rv = g_malloc(sizeof(VikDEM));
/* Header */
f = g_fopen(file, "r");
if ( !f ) {
g_free ( rv );
return NULL;
}
buffer[fread(buffer, 1, DEM_BLOCK_SIZE, f)] = '\0';
if ( ! dem_parse_header ( buffer, rv ) ) {
g_free ( rv );
fclose(f);
return NULL;
}
/* TODO: actually use header -- i.e. GET # OF COLUMNS EXPECTED */
rv->columns = g_ptr_array_new();
rv->n_columns = 0;
/* Column -- Data */
while (! feof(f) ) {
gchar *tmp;
/* read block */
buffer[fread(buffer, 1, DEM_BLOCK_SIZE, f)] = '\0';
/* Fix Fortran-style exponentiation */
tmp = buffer;
while (*tmp) {
if ( *tmp=='D')
*tmp='E';
tmp++;
}
dem_parse_block(buffer, rv, &cur_column, &cur_row);
}
/* TODO - class C records (right now says 'Invalid' and dies) */
fclose(f);
f = NULL;
/* 24k scale */
if ( rv->horiz_units == VIK_DEM_HORIZ_UTM_METERS && rv->n_columns >= 2 )
rv->north_scale = rv->east_scale = GET_COLUMN(rv, 1)->east_west - GET_COLUMN(rv,0)->east_west;
/* FIXME bug in 10m DEM's */
if ( rv->horiz_units == VIK_DEM_HORIZ_UTM_METERS && rv->north_scale == 10 ) {
rv->min_east -= 100;
rv->min_north += 200;
}
return rv;
}
void vik_dem_free ( VikDEM *dem )
{
guint i;
for ( i = 0; i < dem->n_columns; i++)
g_free ( GET_COLUMN(dem, i)->points );
g_ptr_array_free ( dem->columns, TRUE );
g_free ( dem );
}
gint16 vik_dem_get_xy ( VikDEM *dem, guint col, guint row )
{
if ( col < dem->n_columns )
if ( row < GET_COLUMN(dem, col)->n_points )
return GET_COLUMN(dem, col)->points[row];
return VIK_DEM_INVALID_ELEVATION;
}
gint16 vik_dem_get_east_north ( VikDEM *dem, gdouble east, gdouble north )
{
gint col, row;
if ( east > dem->max_east || east < dem->min_east ||
north > dem->max_north || north < dem->min_north )
return VIK_DEM_INVALID_ELEVATION;
col = (gint) floor((east - dem->min_east) / dem->east_scale);
row = (gint) floor((north - dem->min_north) / dem->north_scale);
return vik_dem_get_xy ( dem, col, row );
}
static gboolean dem_get_ref_points_elev_dist(VikDEM *dem,
gdouble east, gdouble north, /* in seconds */
gint16 *elevs, gint16 *dists)
{
int i;
int cols[4], rows[4];
struct LatLon ll[4];
struct LatLon pos;
if ( east > dem->max_east || east < dem->min_east ||
north > dem->max_north || north < dem->min_north )
return FALSE; /* got nothing */
pos.lon = east/3600;
pos.lat = north/3600;
/* order of the data: sw, nw, ne, se */
/* sw */
cols[0] = (gint) floor((east - dem->min_east) / dem->east_scale);
rows[0] = (gint) floor((north - dem->min_north) / dem->north_scale);
ll[0].lon = (dem->min_east + dem->east_scale*cols[0])/3600;
ll[0].lat = (dem->min_north + dem->north_scale*rows[0])/3600;
/* nw */
cols[1] = cols[0];
rows[1] = rows[0] + 1;
ll[1].lon = ll[0].lon;
ll[1].lat = ll[0].lat + (gdouble)dem->north_scale/3600;
/* ne */
cols[2] = cols[0] + 1;
rows[2] = rows[0] + 1;
ll[2].lon = ll[0].lon + (gdouble)dem->east_scale/3600;
ll[2].lat = ll[0].lat + (gdouble)dem->north_scale/3600;
/* se */
cols[3] = cols[0] + 1;
rows[3] = rows[0];
ll[3].lon = ll[0].lon + (gdouble)dem->east_scale/3600;
ll[3].lat = ll[0].lat;
for (i = 0; i < 4; i++) {
if ((elevs[i] = vik_dem_get_xy(dem, cols[i], rows[i])) == VIK_DEM_INVALID_ELEVATION)
return FALSE;
dists[i] = a_coords_latlon_diff(&pos, &ll[i]);
}
#if 0 /* debug */
for (i = 0; i < 4; i++)
fprintf(stderr, "%f:%f:%d:%d ", ll[i].lat, ll[i].lon, dists[i], elevs[i]);
fprintf(stderr, " north_scale=%f\n", dem->north_scale);
#endif
return TRUE; /* all OK */
}
gint16 vik_dem_get_simple_interpol ( VikDEM *dem, gdouble east, gdouble north )
{
int i;
gint16 elevs[4], dists[4];
if (!dem_get_ref_points_elev_dist(dem, east, north, elevs, dists))
return VIK_DEM_INVALID_ELEVATION;
for (i = 0; i < 4; i++) {
if (dists[i] < 1) {
return(elevs[i]);
}
}
gdouble t = (gdouble)elevs[0]/dists[0] + (gdouble)elevs[1]/dists[1] + (gdouble)elevs[2]/dists[2] + (gdouble)elevs[3]/dists[3];
gdouble b = 1.0/dists[0] + 1.0/dists[1] + 1.0/dists[2] + 1.0/dists[3];
return(t/b);
}
gint16 vik_dem_get_shepard_interpol ( VikDEM *dem, gdouble east, gdouble north )
{
int i;
gint16 elevs[4], dists[4];
gint16 max_dist;
gdouble t = 0.0;
gdouble b = 0.0;
if (!dem_get_ref_points_elev_dist(dem, east, north, elevs, dists))
return VIK_DEM_INVALID_ELEVATION;
max_dist = 0;
for (i = 0; i < 4; i++) {
if (dists[i] < 1) {
return(elevs[i]);
}
if (dists[i] > max_dist)
max_dist = dists[i];
}
gdouble tmp;
#if 0 /* derived method by Franke & Nielson. Does not seem to work too well here */
for (i = 0; i < 4; i++) {
tmp = pow((1.0*(max_dist - dists[i])/max_dist*dists[i]), 2);
t += tmp*elevs[i];
b += tmp;
}
#endif
for (i = 0; i < 4; i++) {
tmp = pow((1.0/dists[i]), 2);
t += tmp*elevs[i];
b += tmp;
}
// fprintf(stderr, "DEBUG: tmp=%f t=%f b=%f %f\n", tmp, t, b, t/b);
return(t/b);
}
void vik_dem_east_north_to_xy ( VikDEM *dem, gdouble east, gdouble north, guint *col, guint *row )
{
*col = (gint) floor((east - dem->min_east) / dem->east_scale);
*row = (gint) floor((north - dem->min_north) / dem->north_scale);
if ( *col < 0 ) *col = 0;
if ( *row < 0 ) *row = 0;
}