add z0 to all projections

Author: substack

aea/forward.glsl

@@ -13,7 +13,7 @@ vec3 aea_forward (aea_t t, vec3 p) {
   return vec3(
     rh1 * sin(theta) + t.x0,
     t.rh - rh1 * cos(theta) + t.y0,
-    p.z
+    p.z + t.z0
   );
 }
 vec3 aea_forward (aea_t t, vec2 p) {

aea/t.glsl

@@ -1,6 +1,6 @@
 struct aea_t {
   float lon0, lat0, lat1, lat2;
-  float x0, y0, e3;
+  float x0, y0, z0, e3;
   float ns0, rh, a, c;
   float sphere;
 };

gnom/forward.glsl

@@ -16,13 +16,13 @@ vec3 gnom_forward (gnom_t t, vec3 p) {
     return vec3(
       t.x0+t.a*ksp*cosphi*sin(dlon)/g,
       t.y0+t.a*ksp*(t.cos_p14*sinphi-t.sin_p14*cosphi*coslon)/g,
-      p.z
+      t.z0+p.z
     );
   } else {
     return vec3(
       t.x0+t.infinity_dist*cosphi*sin(dlon),
       t.y0+t.infinity_dist*(t.cos_p14*sinphi-t.sin_p14*cosphi*coslon),
-      p.z
+      t.z0+p.z
     );
   }
 }

gnom/t.glsl

@@ -1,5 +1,5 @@
 struct gnom_t {
-  float lon0, lat0, x0, y0;
+  float lon0, lat0, x0, y0, z0;
   float sin_p14, cos_p14;
   float a, k0;
   float infinity_dist, rc;

index.js

@@ -20,8 +20,9 @@ module.exports = function (str) {
     members = {
       lon0: p.long0,
       lat0: p.lat0,
-      x0: p.x0,
-      y0: p.y0,
+      x0: defined(p.x0,0),
+      y0: defined(p.y0,0),
+      z0: defined(p.z0,0),
       a: defined(p.a,e.a),
       k0: defined(p.k0,1.0),
       sin_p14: Math.sin(p.lat0),
@@ -35,8 +36,9 @@ module.exports = function (str) {
       lat0: p.lat0,
       lat1: p.lat1,
       lat2: p.lat2,
-      x0: p.x0,
-      y0: p.y0,
+      x0: defined(p.x0,0),
+      y0: defined(p.y0,0),
+      z0: defined(p.z0,0),
       a: defined(p.a,e.a),
       sphere: p.sphere ? 1.0 : 0.0
     }
@@ -70,8 +72,9 @@ module.exports = function (str) {
     members = {
       lon0: p.long0,
       lat0: p.lat0,
-      x0: p.x0,
-      y0: p.y0,
+      x0: defined(p.x0,0),
+      y0: defined(p.y0,0),
+      z0: defined(p.z0,0),
       a: defined(p.a,e.a),
       k0: defined(p.k0,1.0),
       sphere: p.sphere ? 1.0 : 0.0,
@@ -104,6 +107,7 @@ module.exports = function (str) {
       lat2: defined(p.lat2, p.lat1),
       x0: defined(p.x0, 0),
       y0: defined(p.y0, 0),
+      z0: defined(p.z0,0),
       k0: defined(p.k0, 1),
       a: a,
       b: b,

lcc/forward.glsl

@@ -18,9 +18,9 @@ vec3 lcc_forward (lcc_t t, vec3 p) {
   }
   float theta = t.ns * (lon - t.lon0);
   return vec3(
-    t.k0*rh1*sin(theta)+t.x0,
-    t.k0*(t.rh-rh1*cos(theta))+t.y0,
-    p.z
+    t.x0+t.k0*rh1*sin(theta),
+    t.y0+t.k0*(t.rh-rh1*cos(theta)),
+    t.z0+p.z
   );
 }
 vec3 lcc_forward (lcc_t t, vec2 p) {

lcc/t.glsl

@@ -1,6 +1,6 @@
 struct lcc_t {
   float lon0, lat0, lat1, lat2;
-  float x0, y0;
+  float x0, y0, z0;
   float a, b, e;
   float k0, ns, f0, rh;
 };

tmerc/forward.glsl

@@ -27,11 +27,11 @@ vec3 tmerc_forward (tmerc_t t, vec3 p) {
   float n = t.a/sqrt(con);
   float ml = t.a*mlfn(t.e0,t.e1,t.e2,t.e3,lat);
   return vec3(
-    t.k0*n*al*(1.0+als/6.0*(1.0-tq2+c+als/20.0
-      *(5.0-18.0*tq2+tq2*tq2+72.0*c-58.0*t.ep2)))+t.x0,
-    t.k0*(ml-t.ml0+n*tq*(als*(0.5+als/24.0*(5.0-tq2+9.0*c+4.0*c*c+als/30.0
-      *(61.0-58.0*tq2+tq2*tq2+600.0*c-330.0*t.ep2)))))+t.y0,
-    p.z
+    t.x0+t.k0*n*al*(1.0+als/6.0*(1.0-tq2+c+als/20.0
+      *(5.0-18.0*tq2+tq2*tq2+72.0*c-58.0*t.ep2))),
+    t.y0+t.k0*(ml-t.ml0+n*tq*(als*(0.5+als/24.0*(5.0-tq2+9.0*c+4.0*c*c+als/30.0
+      *(61.0-58.0*tq2+tq2*tq2+600.0*c-330.0*t.ep2))))),
+    t.z0+p.z
   );
 }
 vec3 tmerc_forward (tmerc_t t, vec2 p) {

tmerc/t.glsl

@@ -1,5 +1,5 @@
 struct tmerc_t {
-  float lon0, lat0, x0, y0;
+  float lon0, lat0, x0, y0, z0;
   float a, sphere, k0;
   float e0, e1, e2, e3, ml0, ep2, es;
 };