static int get_cell(DCELL *result, int fd, double x, double y)
{
static DCELL *row1, *row2;
static int cur_row = -1;
static int row, col;
DCELL *tmp;
if (!row1) {
row1 = Rast_allocate_d_buf();
row2 = Rast_allocate_d_buf();
}
col = (int)floor(x - 0.5);
row = (int)floor(y - 0.5);
x -= col + 0.5;
y -= row + 0.5;
if (row < 0 || row + 1 >= Rast_window_rows() ||
col < 0 || col + 1 >= Rast_window_cols()) {
Rast_set_d_null_value(result, 1);
return 0;
}
if (cur_row != row) {
if (cur_row == row + 1) {
tmp = row1; row1 = row2; row2 = tmp;
Rast_get_d_row(fd, row1, row);
}
else if (cur_row == row - 1) {
tmp = row1; row1 = row2; row2 = tmp;
Rast_get_d_row(fd, row2, row + 1);
}
else {
Rast_get_d_row(fd, row1, row);
Rast_get_d_row(fd, row2, row + 1);
}
cur_row = row;
}
if (Rast_is_d_null_value(&row1[col]) || Rast_is_d_null_value(&row1[col+1]) ||
Rast_is_d_null_value(&row2[col]) || Rast_is_d_null_value(&row2[col+1])) {
Rast_set_d_null_value(result, 1);
return 0;
}
*result = Rast_interp_bilinear(x, y,
row1[col], row1[col+1],
row2[col], row2[col+1]);
return 1;
}
void p_bilinear(struct cache *ibuffer, /* input buffer */
void *obufptr, /* ptr in output buffer */
int cell_type, /* raster map type of obufptr */
double *row_idx, /* row index */
double *col_idx, /* column index */
struct Cell_head *cellhd /* information of output map */
)
{
int row; /* row indices for interp */
int col; /* column indices for interp */
int i, j;
DCELL t, u; /* intermediate slope */
DCELL result; /* result of interpolation */
DCELL c[2][2];
/* cut indices to integer */
row = (int)floor(*row_idx - 0.5);
col = (int)floor(*col_idx - 0.5);
/* check for out of bounds - if out of bounds set NULL value and return */
if (row < 0 || row + 1 >= cellhd->rows || col < 0 || col + 1 >= cellhd->cols) {
Rast_set_null_value(obufptr, 1, cell_type);
return;
}
for (i = 0; i < 2; i++)
for (j = 0; j < 2; j++) {
const DCELL *cellp = CPTR(ibuffer, row + i, col + j);
if (Rast_is_d_null_value(cellp)) {
Rast_set_null_value(obufptr, 1, cell_type);
return;
}
c[i][j] = *cellp;
}
/* do the interpolation */
t = *col_idx - 0.5 - col;
u = *row_idx - 0.5 - row;
result = Rast_interp_bilinear(t, u, c[0][0], c[0][1], c[1][0], c[1][1]);
Rast_set_d_value(obufptr, result, cell_type);
}
/*!
* \brief Extract a cell value from raster map (bilinear interpolation).
*
* Extract a cell value from raster map at given northing and easting
* with a sampled 3x3 window using a bilinear interpolation.
*
* \param fd file descriptor
* \param window region settings
* \param cats categories
* \param north northing position
* \param east easting position
* \param usedesc flag to scan category label
*
* \return cell value at given position
*/
DCELL Rast_get_sample_bilinear(int fd,
const struct Cell_head * window,
struct Categories * cats,
double north, double east, int usedesc)
{
int row, col;
double grid[2][2];
DCELL *arow = Rast_allocate_d_buf();
DCELL *brow = Rast_allocate_d_buf();
double frow, fcol, trow, tcol;
DCELL result;
frow = Rast_northing_to_row(north, window);
fcol = Rast_easting_to_col(east, window);
/* convert northing and easting to row and col, resp */
row = (int)floor(frow - 0.5);
col = (int)floor(fcol - 0.5);
trow = frow - row - 0.5;
tcol = fcol - col - 0.5;
if (row < 0 || row + 1 >= Rast_window_rows() ||
col < 0 || col + 1 >= Rast_window_cols()) {
Rast_set_d_null_value(&result, 1);
goto done;
}
Rast_get_d_row(fd, arow, row);
Rast_get_d_row(fd, brow, row + 1);
if (Rast_is_d_null_value(&arow[col]) ||
Rast_is_d_null_value(&arow[col + 1]) ||
Rast_is_d_null_value(&brow[col]) ||
Rast_is_d_null_value(&brow[col + 1])) {
Rast_set_d_null_value(&result, 1);
goto done;
}
/*-
* now were ready to do bilinear interpolation over
* arow[col], arow[col+1],
* brow[col], brow[col+1]
*/
if (usedesc) {
char *buf;
G_squeeze(buf = Rast_get_c_cat((int *)&(arow[col]), cats));
grid[0][0] = scancatlabel(buf);
G_squeeze(buf = Rast_get_c_cat((CELL *) & (arow[col + 1]), cats));
grid[0][1] = scancatlabel(buf);
G_squeeze(buf = Rast_get_c_cat((CELL *) & (brow[col]), cats));
grid[1][0] = scancatlabel(buf);
G_squeeze(buf = Rast_get_c_cat((CELL *) & (brow[col + 1]), cats));
grid[1][1] = scancatlabel(buf);
}
else {
grid[0][0] = arow[col];
grid[0][1] = arow[col + 1];
grid[1][0] = brow[col];
grid[1][1] = brow[col + 1];
}
result = Rast_interp_bilinear(tcol, trow,
grid[0][0], grid[0][1], grid[1][0],
grid[1][1]);
done:
G_free(arow);
G_free(brow);
return result;
}
int main(int argc, char *argv[])
{
struct GModule *module;
struct Option *rastin, *rastout, *method;
struct History history;
char title[64];
char buf_nsres[100], buf_ewres[100];
struct Colors colors;
int infile, outfile;
DCELL *outbuf;
int row, col;
struct Cell_head dst_w, src_w;
G_gisinit(argv[0]);
module = G_define_module();
G_add_keyword(_("raster"));
G_add_keyword(_("resample"));
module->description =
_("Resamples raster map layers to a finer grid using interpolation.");
rastin = G_define_standard_option(G_OPT_R_INPUT);
rastout = G_define_standard_option(G_OPT_R_OUTPUT);
method = G_define_option();
method->key = "method";
method->type = TYPE_STRING;
method->required = NO;
method->description = _("Interpolation method");
method->options = "nearest,bilinear,bicubic,lanczos";
method->answer = "bilinear";
if (G_parser(argc, argv))
exit(EXIT_FAILURE);
if (G_strcasecmp(method->answer, "nearest") == 0)
neighbors = 1;
else if (G_strcasecmp(method->answer, "bilinear") == 0)
neighbors = 2;
else if (G_strcasecmp(method->answer, "bicubic") == 0)
neighbors = 4;
else if (G_strcasecmp(method->answer, "lanczos") == 0)
neighbors = 5;
else
G_fatal_error(_("Invalid method: %s"), method->answer);
G_get_set_window(&dst_w);
/* set window to old map */
Rast_get_cellhd(rastin->answer, "", &src_w);
/* enlarge source window */
{
double north = Rast_row_to_northing(0.5, &dst_w);
double south = Rast_row_to_northing(dst_w.rows - 0.5, &dst_w);
int r0 = (int)floor(Rast_northing_to_row(north, &src_w) - 0.5) - 2;
int r1 = (int)floor(Rast_northing_to_row(south, &src_w) - 0.5) + 3;
double west = Rast_col_to_easting(0.5, &dst_w);
double east = Rast_col_to_easting(dst_w.cols - 0.5, &dst_w);
int c0 = (int)floor(Rast_easting_to_col(west, &src_w) - 0.5) - 2;
int c1 = (int)floor(Rast_easting_to_col(east, &src_w) - 0.5) + 3;
src_w.south -= src_w.ns_res * (r1 - src_w.rows);
src_w.north += src_w.ns_res * (-r0);
src_w.west -= src_w.ew_res * (-c0);
src_w.east += src_w.ew_res * (c1 - src_w.cols);
src_w.rows = r1 - r0;
src_w.cols = c1 - c0;
}
Rast_set_input_window(&src_w);
/* allocate buffers for input rows */
for (row = 0; row < neighbors; row++)
bufs[row] = Rast_allocate_d_input_buf();
cur_row = -100;
/* open old map */
infile = Rast_open_old(rastin->answer, "");
/* reset window to current region */
Rast_set_output_window(&dst_w);
outbuf = Rast_allocate_d_output_buf();
/* open new map */
outfile = Rast_open_new(rastout->answer, DCELL_TYPE);
switch (neighbors) {
case 1: /* nearest */
for (row = 0; row < dst_w.rows; row++) {
double north = Rast_row_to_northing(row + 0.5, &dst_w);
double maprow_f = Rast_northing_to_row(north, &src_w) - 0.5;
int maprow0 = (int)floor(maprow_f + 0.5);
G_percent(row, dst_w.rows, 2);
read_rows(infile, maprow0);
for (col = 0; col < dst_w.cols; col++) {
double east = Rast_col_to_easting(col + 0.5, &dst_w);
double mapcol_f = Rast_easting_to_col(east, &src_w) - 0.5;
int mapcol0 = (int)floor(mapcol_f + 0.5);
double c = bufs[0][mapcol0];
if (Rast_is_d_null_value(&c)) {
Rast_set_d_null_value(&outbuf[col], 1);
}
else {
outbuf[col] = c;
}
}
Rast_put_d_row(outfile, outbuf);
}
break;
case 2: /* bilinear */
for (row = 0; row < dst_w.rows; row++) {
double north = Rast_row_to_northing(row + 0.5, &dst_w);
double maprow_f = Rast_northing_to_row(north, &src_w) - 0.5;
int maprow0 = (int)floor(maprow_f);
double v = maprow_f - maprow0;
G_percent(row, dst_w.rows, 2);
read_rows(infile, maprow0);
for (col = 0; col < dst_w.cols; col++) {
double east = Rast_col_to_easting(col + 0.5, &dst_w);
double mapcol_f = Rast_easting_to_col(east, &src_w) - 0.5;
int mapcol0 = (int)floor(mapcol_f);
int mapcol1 = mapcol0 + 1;
double u = mapcol_f - mapcol0;
double c00 = bufs[0][mapcol0];
double c01 = bufs[0][mapcol1];
double c10 = bufs[1][mapcol0];
double c11 = bufs[1][mapcol1];
if (Rast_is_d_null_value(&c00) ||
Rast_is_d_null_value(&c01) ||
Rast_is_d_null_value(&c10) || Rast_is_d_null_value(&c11)) {
Rast_set_d_null_value(&outbuf[col], 1);
}
else {
outbuf[col] = Rast_interp_bilinear(u, v, c00, c01, c10, c11);
}
}
Rast_put_d_row(outfile, outbuf);
}
break;
case 4: /* bicubic */
for (row = 0; row < dst_w.rows; row++) {
double north = Rast_row_to_northing(row + 0.5, &dst_w);
double maprow_f = Rast_northing_to_row(north, &src_w) - 0.5;
int maprow1 = (int)floor(maprow_f);
int maprow0 = maprow1 - 1;
double v = maprow_f - maprow1;
G_percent(row, dst_w.rows, 2);
read_rows(infile, maprow0);
for (col = 0; col < dst_w.cols; col++) {
double east = Rast_col_to_easting(col + 0.5, &dst_w);
double mapcol_f = Rast_easting_to_col(east, &src_w) - 0.5;
int mapcol1 = (int)floor(mapcol_f);
int mapcol0 = mapcol1 - 1;
int mapcol2 = mapcol1 + 1;
int mapcol3 = mapcol1 + 2;
double u = mapcol_f - mapcol1;
double c00 = bufs[0][mapcol0];
double c01 = bufs[0][mapcol1];
double c02 = bufs[0][mapcol2];
double c03 = bufs[0][mapcol3];
double c10 = bufs[1][mapcol0];
double c11 = bufs[1][mapcol1];
double c12 = bufs[1][mapcol2];
double c13 = bufs[1][mapcol3];
double c20 = bufs[2][mapcol0];
double c21 = bufs[2][mapcol1];
double c22 = bufs[2][mapcol2];
double c23 = bufs[2][mapcol3];
double c30 = bufs[3][mapcol0];
double c31 = bufs[3][mapcol1];
double c32 = bufs[3][mapcol2];
double c33 = bufs[3][mapcol3];
if (Rast_is_d_null_value(&c00) ||
Rast_is_d_null_value(&c01) ||
Rast_is_d_null_value(&c02) ||
Rast_is_d_null_value(&c03) ||
Rast_is_d_null_value(&c10) ||
Rast_is_d_null_value(&c11) ||
Rast_is_d_null_value(&c12) ||
Rast_is_d_null_value(&c13) ||
Rast_is_d_null_value(&c20) ||
Rast_is_d_null_value(&c21) ||
Rast_is_d_null_value(&c22) ||
Rast_is_d_null_value(&c23) ||
Rast_is_d_null_value(&c30) ||
Rast_is_d_null_value(&c31) ||
Rast_is_d_null_value(&c32) || Rast_is_d_null_value(&c33)) {
Rast_set_d_null_value(&outbuf[col], 1);
}
else {
outbuf[col] = Rast_interp_bicubic(u, v,
c00, c01, c02, c03,
c10, c11, c12, c13,
c20, c21, c22, c23,
c30, c31, c32, c33);
}
}
Rast_put_d_row(outfile, outbuf);
}
break;
case 5: /* lanczos */
for (row = 0; row < dst_w.rows; row++) {
double north = Rast_row_to_northing(row + 0.5, &dst_w);
double maprow_f = Rast_northing_to_row(north, &src_w) - 0.5;
int maprow1 = (int)floor(maprow_f + 0.5);
int maprow0 = maprow1 - 2;
double v = maprow_f - maprow1;
G_percent(row, dst_w.rows, 2);
read_rows(infile, maprow0);
for (col = 0; col < dst_w.cols; col++) {
double east = Rast_col_to_easting(col + 0.5, &dst_w);
double mapcol_f = Rast_easting_to_col(east, &src_w) - 0.5;
int mapcol2 = (int)floor(mapcol_f + 0.5);
int mapcol0 = mapcol2 - 2;
int mapcol4 = mapcol2 + 2;
double u = mapcol_f - mapcol2;
double c[25];
int ci = 0, i, j, do_lanczos = 1;
for (i = 0; i < 5; i++) {
for (j = mapcol0; j <= mapcol4; j++) {
c[ci] = bufs[i][j];
if (Rast_is_d_null_value(&(c[ci]))) {
Rast_set_d_null_value(&outbuf[col], 1);
do_lanczos = 0;
break;
}
ci++;
}
if (!do_lanczos)
break;
}
if (do_lanczos) {
outbuf[col] = Rast_interp_lanczos(u, v, c);
}
}
Rast_put_d_row(outfile, outbuf);
}
break;
}
G_percent(dst_w.rows, dst_w.rows, 2);
Rast_close(infile);
Rast_close(outfile);
/* record map metadata/history info */
sprintf(title, "Resample by %s interpolation", method->answer);
Rast_put_cell_title(rastout->answer, title);
Rast_short_history(rastout->answer, "raster", &history);
Rast_set_history(&history, HIST_DATSRC_1, rastin->answer);
G_format_resolution(src_w.ns_res, buf_nsres, src_w.proj);
G_format_resolution(src_w.ew_res, buf_ewres, src_w.proj);
Rast_format_history(&history, HIST_DATSRC_2,
"Source map NS res: %s EW res: %s",
buf_nsres, buf_ewres);
Rast_command_history(&history);
Rast_write_history(rastout->answer, &history);
/* copy color table from source map */
if (Rast_read_colors(rastin->answer, "", &colors) < 0)
G_fatal_error(_("Unable to read color table for %s"), rastin->answer);
Rast_mark_colors_as_fp(&colors);
Rast_write_colors(rastout->answer, G_mapset(), &colors);
return (EXIT_SUCCESS);
}
