float RSL_get_value_from_cappi(Cappi *cappi, float rng, float azm)
{
return RSL_get_value_from_sweep(cappi->sweep, azm, rng);
}
unsigned char *RSL_rhi_sweep_to_cart(Sweep *s, int xdim, int ydim,
float range, int vert_scale)
{
int x, y, xx, yy, i, j;
float angle, r;
float val;
int the_index;
static unsigned char *rhi_cart_image = NULL;
static unsigned char *buffer = NULL;
if (s == NULL) return NULL;
if (buffer == NULL)
buffer = (unsigned char *)calloc(xdim*ydim, sizeof(unsigned char));
if (rhi_cart_image == NULL)
rhi_cart_image = (unsigned char *)calloc(xdim*ydim, sizeof(unsigned char));
memset(buffer, (unsigned char)0, xdim*ydim);
memset(rhi_cart_image, (unsigned char)0, xdim*ydim);
for (y=0; y<xdim; y++)
for (x=0; x<ydim; x++) {
if (x != 0)
angle = (float)atan((double)y/(double)x)*180.0/3.14159;
else
angle = 90.0;
angle = 90.0 - angle;
r = (float)sqrt((double)x*x + (double)y*y);
if (r > range)
val = BADVAL;
else
val = RSL_get_value_from_sweep(s, angle, r);
/* A vertical sweep extends from 0 deg to perhaps 25 deg in
elevation. For proper orientation of a displayed rhi
vertical sweep:
1. reflect image about the line y=x .
2. translate image downward so that radar site is located
at the bottom left corner of the image. The sweep will
then extend upward from the bottom of the image.
*/
xx = y; /* reflection about line y=x */
yy = x; /* reflection about line y=x */
the_index = (ydim - 1 - yy)*xdim + xx;
if (val == BADVAL || val == NOTFOUND_V || val == NOTFOUND_H)
buffer[the_index] = (unsigned char) 0;
else if (val >= 0)
buffer[the_index] = (unsigned char) val;
else
buffer[the_index] = (unsigned char) (256+val);
}
/* To see details in the sweep, it is customary to scale the image
so that the scale of the vertical axis is 5 or 10 times the scale
of the horizontal axis.
Copy each row of pixel values from buffer[] a constant multiple
number of times into rhi_cart_image[], in order to vertically
expand the image.
*/
for (j=0; j<ydim/vert_scale; j++)
for (i=1; i<=vert_scale; i++)
memcpy(&rhi_cart_image[(ydim - i - vert_scale*j)*xdim],
&buffer[(ydim - 1 - j)*xdim], xdim);
return rhi_cart_image;
}
