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ISEA: Removing extraneous multiplications, unused code
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- NOTE: There may have been an undocumented +rescale= parameter which
will no longer work
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@jerstlouis
jerstlouis committed Aug 14, 2024
1 parent 5f0aedf commit 7874a3a
Showing 1 changed file with 35 additions and 102 deletions.
137 changes: 35 additions & 102 deletions src/projections/isea.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -231,17 +231,7 @@ static void hexbin2(double width, double x, double y, long *i, long *j) {
#define numIcosahedronFaces 20

namespace { // anonymous namespace
enum isea_address_form {
ISEA_GEO,
ISEA_Q2DI,
ISEA_SEQNUM,
ISEA_INTERLEAVE,
ISEA_PLANE,
ISEA_Q2DD,
ISEA_PROJTRI,
ISEA_VERTEX2DD,
ISEA_HEX
};
enum isea_address_form { ISEA_PLANE, ISEA_Q2DI, ISEA_Q2DD, ISEA_HEX };

struct isea_sincos {
double s, c;
Expand Down Expand Up @@ -318,17 +308,13 @@ namespace { // anonymous namespace
class ISEAPlanarProjection;

struct pj_isea_data {
int polyhedron; /* ignored, icosahedron */
double o_lat, o_lon, o_az; /* orientation, radians */
int topology; /* ignored, hexagon */
int aperture; /* valid values depend on partitioning method */
int resolution;
double radius; /* radius of the earth in meters, ignored 1.0 */
int output; /* an isea_address_form */
int triangle; /* triangle of last transformed point */
int quad; /* quad of last transformed point */
isea_address_form output; /* an isea_address_form */
int triangle; /* triangle of last transformed point */
int quad; /* quad of last transformed point */
isea_sincos vertexLatSinCos[numIcosahedronFaces];
unsigned long serial;

double R2;
double Rprime;
Expand Down Expand Up @@ -581,14 +567,11 @@ static int isea_grid_init(struct pj_isea_data *g) {
if (!g)
return 0;

g->polyhedron = numIcosahedronFaces;
g->o_lat = ISEA_STD_LAT;
g->o_lon = ISEA_STD_LONG;
g->o_az = 0.0;
g->aperture = 4;
g->resolution = 6;
g->radius = 1.0;
g->topology = 6;

for (i = 0; i < numIcosahedronFaces; i++) {
const GeoPoint *c = &facesCenterDodecahedronVertices[i];
Expand Down Expand Up @@ -625,8 +608,6 @@ static int isea_transform(struct pj_isea_data *g, struct GeoPoint *in,
i = isea_ctran(&pole, in, g->o_az);

tri = isea_snyder_forward(g, &i, out);
out->x *= g->radius;
out->y *= g->radius;
g->triangle = tri;

return tri;
Expand All @@ -652,15 +633,13 @@ static void isea_rotate(struct isea_pt *pt, double degrees) {
pt->y = y;
}

static int isea_tri_plane(int tri, struct isea_pt *pt, double radius) {
static int isea_tri_plane(int tri, struct isea_pt *pt) {
struct isea_pt tc; /* center of triangle */

if (DOWNTRI(tri)) {
isea_rotate(pt, 180.0);
}
tc = isea_triangle_xy(tri);
tc.x *= radius;
tc.y *= radius;
pt->x += tc.x;
pt->y += tc.y;

Expand Down Expand Up @@ -850,40 +829,6 @@ static int isea_ptdi(struct pj_isea_data *g, int tri, struct isea_pt *pt,
return quadz;
}

/* q2di to seqnum */

static long isea_disn(struct pj_isea_data *g, int quadz, struct isea_pt *di) {
long sidelength;
long sn, height;
long hexes;

if (quadz == 0) {
g->serial = 1;
return g->serial;
}
/* hexes in a quad */
hexes = lround(pow(static_cast<double>(g->aperture),
static_cast<double>(g->resolution)));
if (quadz == 11) {
g->serial = 1 + 10 * hexes + 1;
return g->serial;
}
if (g->aperture == 3 && g->resolution % 2 == 1) {
height = lround(floor((pow(g->aperture, (g->resolution - 1) / 2.0))));
sn = ((long)di->x) * height;
sn += ((long)di->y) / height;
sn += (quadz - 1) * hexes;
sn += 2;
} else {
sidelength = lround((pow(g->aperture, g->resolution / 2.0)));
sn = lround(
floor(((quadz - 1) * hexes + sidelength * di->x + di->y + 2)));
}

g->serial = sn;
return sn;
}

/* TODO just encode the quad in the d or i coordinate
* quad is 0-11, which can be four bits.
* d' = d << 4 + q, d = d' >> 4, q = d' & 0xf
Expand Down Expand Up @@ -957,49 +902,35 @@ static int isea_hex(struct pj_isea_data *g, int tri, struct isea_pt *pt,

static struct isea_pt isea_forward(struct pj_isea_data *g,
struct GeoPoint *in) {
int tri;
struct isea_pt out, coord;

tri = isea_transform(g, in, &out);

if (g->output == ISEA_PLANE) {
isea_tri_plane(tri, &out, g->radius);
return out;
}

/* convert to isea standard triangle size */
out.x = out.x / g->radius * ISEA_SCALE;
out.y = out.y / g->radius * ISEA_SCALE;
out.x += 0.5;
out.y += 2.0 * .14433756729740644112;

switch (g->output) {
case ISEA_PROJTRI:
/* nothing to do, already in projected triangle */
break;
case ISEA_VERTEX2DD:
g->quad = isea_ptdd(tri, &out);
break;
case ISEA_Q2DD:
/* Same as above, we just don't print as much */
g->quad = isea_ptdd(tri, &out);
break;
case ISEA_Q2DI:
g->quad = isea_ptdi(g, tri, &out, &coord);
return coord;
break;
case ISEA_SEQNUM:
isea_ptdi(g, tri, &out, &coord);
/* disn will set g->serial */
isea_disn(g, g->quad, &coord);
return coord;
break;
case ISEA_HEX:
isea_hex(g, tri, &out, &coord);
return coord;
break;
isea_pt out;
int tri = isea_transform(g, in, &out);

if (g->output == ISEA_PLANE)
isea_tri_plane(tri, &out);
else {
isea_pt coord;

/* convert to isea standard triangle size */
out.x *= ISEA_SCALE; // / g->radius;
out.y *= ISEA_SCALE; // / g->radius;
out.x += 0.5;
out.y += 2.0 * .14433756729740644112;

switch (g->output) {
case ISEA_PLANE:
/* already handled above -- GCC should not be complaining */
case ISEA_Q2DD:
/* Same as above, we just don't print as much */
g->quad = isea_ptdd(tri, &out);
break;
case ISEA_Q2DI:
g->quad = isea_ptdi(g, tri, &out, &coord);
return coord;
case ISEA_HEX:
isea_hex(g, tri, &out, &coord);
return coord;
}
}

return out;
}

Expand Down Expand Up @@ -1098,9 +1029,11 @@ PJ *PJ_PROJECTION(isea) {
}
}

/* REVIEW: Was this an undocumented +rescale= parameter?
if (pj_param(P->ctx, P->params, "trescale").i) {
Q->radius = ISEA_SCALE;
}
*/

if (pj_param(P->ctx, P->params, "tresolution").i) {
Q->resolution = pj_param(P->ctx, P->params, "iresolution").i;
Expand Down

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