SEXP
R_makecartogram(SEXP r_pop, SEXP gridx, SEXP gridy, SEXP r_dims, SEXP blur)
{
int *dims;
double **pop;
int i, n;
SEXP ans;
dims = INTEGER(r_dims);
/* Note that if we get an interrupt, this will not be freed!
We may change cart.c to use R_alloc().
*/
cart_makews(dims[0], dims[1]);
pop = (double **) R_alloc(sizeof(double *), dims[0]);
if(TYPEOF(r_pop) == VECSXP) {
/* This leads to non-contiguous values. Not certain if this is
* allowed in the cart.c code. */
for(i = 0; i < dims[0]; i++) {
pop[i] = REAL(VECTOR_ELT(r_pop, i));
}
} else {
/* Given a numeric matrix, so just pull out the pointers to
the beginning of each column. Since we are using the
columns for the Y values, this gives us the form of a 2D
array in C with pop[i] giving a vector/array of the y's.
*/
double *data = REAL(r_pop);
for(i = 0; i < dims[0]; i++) {
pop[i] = data + i * dims[1];
}
}
INTERRUPT
cart_transform(pop, dims[0], dims[1]);
PROTECT(ans = allocVector(VECSXP, 2));
SET_VECTOR_ELT(ans, 0, gridx = Rf_duplicate(gridx));
SET_VECTOR_ELT(ans, 1, gridy = Rf_duplicate(gridy));
INTERRUPT
cart_makecart(REAL(gridx), REAL(gridy), Rf_length(gridx), dims[0], dims[1], REAL(blur)[0]);
INTERRUPT
cart_freews(dims[0], dims[1]);
UNPROTECT(1);
return(ans);
}
void main(int argc, char *argv[])
{
int xsize,ysize;
double *gridx,*gridy; // Array for grid points
double **rho; // Initial population density
FILE *infp;
FILE *outfp;
/* Read the command-line parameters and open the input and output files */
if (argc<5) {
fprintf(stderr,"Usage: %s xsize ysize inputfile outputfile\n",argv[0]);
exit(1);
}
xsize = atoi(argv[1]);
if (xsize<1) {
fprintf(stderr,"%s: xsize botched\n",argv[0]);
exit(2);
}
ysize = atoi(argv[2]);
if (ysize<1) {
fprintf(stderr,"%s: ysize botched\n",argv[0]);
exit(3);
}
infp = fopen(argv[3],"r");
if (infp==NULL) {
fprintf(stderr,"%s: unable to open file `%s'\n",argv[0],argv[3]);
exit(4);
}
outfp = fopen(argv[4],"w");
if (outfp==NULL) {
fprintf(stderr,"%s: unable to open file `%s'\n",argv[0],argv[4]);
exit(5);
}
/* Allocate space for the cartogram code to use */
cart_makews(xsize,ysize);
/* Read in the population data, transform it, then destroy it again */
rho = cart_dmalloc(xsize,ysize);
if (readpop(infp,rho,xsize,ysize)) {
fprintf(stderr,"%s: density file contains too few or incorrect data\n",
argv[0]);
exit(6);
}
cart_transform(rho,xsize,ysize);
cart_dfree(rho);
/* Create the grid of points */
gridx = malloc((xsize+1)*(ysize+1)*sizeof(double));
gridy = malloc((xsize+1)*(ysize+1)*sizeof(double));
creategrid(gridx,gridy,xsize,ysize);
/* Make the cartogram */
cart_makecart(gridx,gridy,(xsize+1)*(ysize+1),xsize,ysize,0.0);
/* Write out the final positions of the grid points */
writepoints(outfp,gridx,gridy,(xsize+1)*(ysize+1));
/* Free up the allocated space */
cart_freews(xsize,ysize);
free(gridx);
free(gridy);
/* Close the input and output files */
fclose(infp);
fclose(outfp);
}
int equalize_density(char *infile, char *outfile, int fast, int accurate) {
int xsize, ysize; // Size of the density grid.
double *gridx, *gridy; // Array for grid
double **rho; // Initial population density
GDALDatasetH hDataset; // The input density raster file.
GDALRasterBandH hBand; // The raster band we are going to use.
FILE *outfp; // The morphing file (a text file).
double adfGeoTransform[6]; // For the georeference of the raster.
// Register all GDAL drivers.
GDALAllRegister();
#if defined (_OPENMP)
omp_set_num_threads(omp_get_num_procs());
#endif
hDataset = GDALOpen(infile, GA_ReadOnly);
if (hDataset == NULL) {
fprintf(stderr,"Error. Unable to open file `%s'\n", infile);
exit(1);
}
outfp = fopen(outfile, "w");
if (outfp == NULL) {
fprintf(stderr,"Error. Unable to open file `%s'\n", outfile);
exit(1);
}
// Get the raster band for the dataset; we are using the first band.
hBand = GDALGetRasterBand(hDataset, 1);
if (hBand == NULL) {
fprintf(stderr, "Error. Unable to read band 1 in file `%s'\n", infile);
exit(1);
}
// Determine the raster size
xsize = GDALGetRasterBandXSize(hBand);
ysize = GDALGetRasterBandYSize(hBand);
// Allocate space for the cartogram code to use
cart_makews(xsize, ysize);
// Read in the population data, transform it, then destroy it again
rho = cart_dmalloc(xsize, ysize);
if (readpop(hBand, rho, xsize, ysize)) {
fprintf(stderr,"Error. Density file contains too few or incorrect data\n");
exit(1);
}
cart_transform(rho, xsize, ysize);
cart_dfree(rho);
// Create the grid of points
gridx = malloc((xsize+1)*(ysize+1)*sizeof(double));
gridy = malloc((xsize+1)*(ysize+1)*sizeof(double));
creategrid(gridx, gridy, xsize, ysize);
// Compute the cartogram
cart_makecart(gridx, gridy, (xsize+1)*(ysize+1), xsize, ysize, 0.0);
// Write out the final positions of the grid points
GDALGetGeoTransform(hDataset, adfGeoTransform);
writepoints(outfp, gridx, gridy, xsize, ysize, adfGeoTransform);
//writepoints(outfp, gridx, gridy, (xsize+1)*(ysize+1));
// Free up the allocated memory
cart_freews(xsize, ysize);
free(gridx);
free(gridy);
// Close the input and output files
GDALClose(hDataset);
fclose(outfp);
return 0;
}
