com/gradoservice/proj4as/ProjProjection.as

   1 package com.gradoservice.proj4as
   2 {
   3         import com.gradoservice.proj4as.proj.*;
   4
   5         public class ProjProjection
   6         {
   7         /**
   8            * Property: readyToUse
   9            * Flag to indicate if initialization is complete for this Proj object
  10            */
  11           public var readyToUse:Boolean = false;
  12
  13           /**
  14            * Property: title
  15            * The title to describe the projection
  16            */
  17          protected var projParams:ProjParams = new ProjParams();
  18
  19          static public const defs:Object = {
  20                         'EPSG:900913': "+title=Google Mercator EPSG:900913 +proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +no_defs",
  21                         'WGS84': "+title=long/lat:WGS84 +proj=longlat +ellps=WGS84 +datum=WGS84 +units=degrees",
  22                         'EPSG:4326': "+title=long/lat:WGS84 +proj=longlat +a=6378137.0 +b=6356752.31424518 +ellps=WGS84 +datum=WGS84 +units=degrees",
  23                         'EPSG:4269': "+title=long/lat:NAD83 +proj=longlat +a=6378137.0 +b=6356752.31414036 +ellps=GRS80 +datum=NAD83 +units=degrees",
  24                         'EPSG:32639': "+title=WGS 84 / UTM zone 39N +proj=utm +zone=39 +ellps=WGS84 +datum=WGS84 +units=m +no_defs",
  25                         'EPSG:27700': "+proj=tmerc +lat_0=49 +lon_0=-2 +k=0.9996012717 +x_0=400000 +y_0=-100000 +ellps=airy +datum=OSGB36 +units=m +no_defs"
  26                 }
  27
  28
  29
  30           protected var proj:IProjection;
  31
  32                 public function get srsCode():String
  33                 {
  34                         return projParams.srsCode;
  35                 }
  36
  37                 public function get srsProjNumber():String
  38                 {
  39                         return projParams.srsProjNumber;
  40                 }
  41
  42                 public function get projName():String
  43                 {
  44                         return projParams.projName;
  45                 }
  46
  47                 public function get datum():Datum
  48                 {
  49                         return projParams.datum;
  50                 }
  51
  52                 public function get datumCode():String
  53                 {
  54                         return projParams.datumCode;
  55                 }
  56
  57                 public function get from_greenwich():Number
  58                 {
  59                         return projParams.from_greenwich;
  60                 }
  61
  62                 public function get to_meter():Number
  63                 {
  64                         return projParams.to_meter;
  65                 }
  66
  67                 public function get a():Number
  68                 {
  69                         return projParams.a;
  70                 }
  71
  72                 public function get b():Number
  73                 {
  74                         return projParams.b;
  75                 }
  76
  77                 public function get ep2():Number
  78                 {
  79                         return projParams.ep2;
  80                 }
  81
  82                 public function get es():Number
  83                 {
  84                         return projParams.es;
  85                 }
  86
  87                 public function get datum_params():Array
  88                 {
  89                         return projParams.datum_params;
  90                 }
  91
  92                 public function ProjProjection(srsCode:String)
  93                 {
  94                         this.projParams.srsCode = srsCode.toUpperCase();
  95
  96                       if (this.projParams.srsCode.indexOf("EPSG") == 0) {
  97                           this.projParams.srsAuth = 'epsg';
  98                           this.projParams.srsProjNumber = this.projParams.srsCode.substring(5);
  99                       // DGR 2007-11-20 : authority IGNF
 100                       } else if (this.projParams.srsCode.indexOf("IGNF") == 0) {
 101                           this.projParams.srsAuth = 'IGNF';
 102                           this.projParams.srsProjNumber = this.projParams.srsCode.substring(5);
 103                       // DGR 2008-06-19 : pseudo-authority CRS for WMS
 104                       } else if (this.projParams.srsCode.indexOf("CRS") == 0) {
 105                           this.projParams.srsAuth = 'CRS';
 106                           this.projParams.srsProjNumber = this.projParams.srsCode.substring(4);
 107                       } else {
 108                           this.projParams.srsAuth = '';
 109                           this.projParams.srsProjNumber = this.projParams.srsCode;
 110                       }
 111                       this.loadProjDefinition();
 112                 }
 113
 114                 private function loadProjDefinition():void
 115                 {
 116                         if (this.srsCode!=null && ProjProjection.defs[this.srsCode]!=null)
 117                         {
 118                                 this.parseDef(ProjProjection.defs[this.projParams.srsCode]);
 119                                 this.initTransforms();
 120                         }
 121                 }
 122
 123                 protected function initTransforms():void
 124                         {
 125                         switch (this.projParams.projName)
 126                         {
 127                                 case "aea": this.proj = new ProjAea(this.projParams); break;
 128                                 case "aeqd": this.proj = new ProjAeqd(this.projParams); break;
 129                                 case "eqc": this.proj = new ProjEqc(this.projParams); break;
 130                                 case "eqdc": this.proj = new ProjEqdc(this.projParams); break;
 131                                 case "equi": this.proj = new ProjEqui(this.projParams); break;
 132                                 case "gauss": this.proj = new ProjGauss(this.projParams); break;
 133                                 case "gstmerc": this.proj = new ProjGstmerc(this.projParams); break;
 134                                 case "laea": this.proj = new ProjLaea(this.projParams); break;
 135                                 case "lcc": this.proj = new ProjLcc(this.projParams); break;
 136                                 case "longlat": this.proj = new ProjLonglat(this.projParams); break;
 137                                 case "merc": this.proj = new ProjMerc(this.projParams); break;
 138                                 case "mill": this.proj = new ProjMill(this.projParams); break;
 139                                 case "moll": this.proj = new ProjMoll(this.projParams); break;
 140                                 case "nzmg": this.proj = new ProjNzmg(this.projParams); break;
 141                                 case "omerc": this.proj = new ProjOmerc(this.projParams); break;
 142                                 case "ortho": this.proj = new ProjOrtho(this.projParams); break;
 143                                 case "sinu": this.proj = new ProjSinu(this.projParams); break;
 144                                 case "omerc": this.proj = new ProjOmerc(this.projParams); break;
 145                                 case "stere": this.proj = new ProjStere(this.projParams); break;
 146                                 case "sterea": this.proj = new ProjSterea(this.projParams); break;
 147                                 case "tmerc": this.proj = new ProjTmerc(this.projParams); break;
 148                                 case "utm": this.proj = new ProjUtm(this.projParams); break;
 149                                 case "vandg": this.proj = new ProjVandg(this.projParams); break;
 150                         }
 151                         if (this.proj!=null) {
 152                                 this.proj.init();
 153                                 this.readyToUse = true;
 154                         }
 155                         }
 156
 157                 private function parseDef(definition:String):void
 158                 {
 159                 var paramName:String = '';
 160                 var paramVal:String = '';
 161                 var paramArray:Array=definition.split("+");
 162                         for (var prop:int=0; prop<paramArray.length; prop++) {
 163                                   var property:Array = paramArray[prop].split("=");
 164                                   paramName = property[0].toLowerCase();
 165                                   paramVal = property[1];
 166
 167                                   switch (paramName.replace(/\s/gi,"")) {  // trim out spaces
 168                                       case "": break;   // throw away nameless parameter
 169                                       case "title":  this.projParams.title = paramVal; break;
 170                                       case "proj":   this.projParams.projName =  paramVal.replace(/\s/gi,""); break;
 171                                       case "units":  this.projParams.units = paramVal.replace(/\s/gi,""); break;
 172                                       case "datum":  this.projParams.datumCode = paramVal.replace(/\s/gi,""); break;
 173                                       case "nadgrids": this.projParams.nagrids = paramVal.replace(/\s/gi,""); break;
 174                                       case "ellps":  this.projParams.ellps = paramVal.replace(/\s/gi,""); break;
 175                                       case "a":      this.projParams.a =  parseFloat(paramVal); break;  // semi-major radius
 176                                       case "b":      this.projParams.b =  parseFloat(paramVal); break;  // semi-minor radius
 177                                       // DGR 2007-11-20
 178                                       case "rf":     this.projParams.rf = parseFloat(paramVal); break; // inverse flattening rf= a/(a-b)
 179                                       case "lat_0":  this.projParams.lat0 = parseFloat(paramVal)*ProjConstants.D2R; break;        // phi0, central latitude
 180                                       case "lat_1":  this.projParams.lat1 = parseFloat(paramVal)*ProjConstants.D2R; break;        //standard parallel 1
 181                                       case "lat_2":  this.projParams.lat2 = parseFloat(paramVal)*ProjConstants.D2R; break;        //standard parallel 2
 182                                       case "lat_ts": this.projParams.lat_ts = parseFloat(paramVal)*ProjConstants.D2R; break;      // used in merc and eqc
 183                                       case "lon_0":  this.projParams.long0 = parseFloat(paramVal)*ProjConstants.D2R; break;       // lam0, central longitude
 184                                       case "alpha":  this.projParams.alpha =  parseFloat(paramVal)*ProjConstants.D2R; break;  //for somerc projection
 185                                       case "lonc":   this.projParams.longc = parseFloat(paramVal)*ProjConstants.D2R; break;       //for somerc projection
 186                                       case "x_0":    this.projParams.x0 = parseFloat(paramVal); break;  // false easting
 187                                       case "y_0":    this.projParams.y0 = parseFloat(paramVal); break;  // false northing
 188                                       case "k_0":    this.projParams.k0 = parseFloat(paramVal); break;  // projection scale factor
 189                                       case "k":      this.projParams.k0 = parseFloat(paramVal); break;  // both forms returned
 190                                       case "R_A":    this.projParams.R_A = true; break;   //Spheroid radius
 191                                       case "zone":   this.projParams.zone = parseInt(paramVal); break;  // UTM Zone
 192                                       case "south":   this.projParams.utmSouth = true; break;  // UTM north/south
 193                                       case "towgs84":this.projParams.datum_params = paramVal.split(","); break;
 194                                       case "to_meter": this.projParams.to_meter = parseFloat(paramVal); break; // cartesian scaling
 195                                       case "from_greenwich": this.projParams.from_greenwich = parseFloat(paramVal)*ProjConstants.D2R; break;
 196                                       // DGR 2008-07-09 : if pm is not a well-known prime meridian take
 197                                       // the value instead of 0.0, then convert to radians
 198                                       case "pm":     paramVal = paramVal.replace(/\s/gi,"");
 199                                                      this.projParams.from_greenwich = ProjConstants.PrimeMeridian[paramVal] ?
 200                                                         ProjConstants.PrimeMeridian[paramVal] : parseFloat(paramVal);
 201                                                      this.projParams.from_greenwich *= ProjConstants.D2R;
 202                                                      break;
 203                                       case "no_defs": break;
 204                                       default: trace("Unrecognized parameter: " + paramName); break;
 205                                   } // switch()
 206                               } // for paramArray
 207                               this.deriveConstants();
 208
 209                 }
 210
 211                 private function deriveConstants():void
 212                 {
 213                 if (this.projParams.nagrids == '@null') this.projParams.datumCode = 'none';
 214                 if (this.projParams.datumCode && this.projParams.datumCode != 'none')
 215                 {
 216                 var datumDef:Object = ProjConstants.Datum[this.projParams.datumCode];
 217                 if (datumDef)
 218                         {
 219                         this.projParams.datum_params = datumDef.towgs84.split(',');
 220                         this.projParams.ellps = datumDef.ellipse;
 221                         this.projParams.datumName = datumDef.datumName ? datumDef.datumName : this.projParams.datumCode;
 222                         }
 223                 }
 224
 225               if (!this.projParams.a) {    // do we have an ellipsoid?
 226                   var ellipse:Object = ProjConstants.Ellipsoid[this.projParams.ellps] ? ProjConstants.Ellipsoid[this.projParams.ellps] : ProjConstants.Ellipsoid['WGS84'];
 227                   extend(this.projParams, ellipse);
 228               }
 229               if (this.projParams.rf && !this.projParams.b) this.projParams.b = (1.0 - 1.0/this.projParams.rf) * this.projParams.a;
 230               if (Math.abs(this.projParams.a - this.projParams.b)<ProjConstants.EPSLN) {
 231                 this.projParams.sphere = true;
 232                 this.projParams.b= this.projParams.a;
 233               }
 234               this.projParams.a2 = this.projParams.a * this.projParams.a;          // used in geocentric
 235               this.projParams.b2 = this.projParams.b * this.projParams.b;          // used in geocentric
 236               this.projParams.es = (this.projParams.a2-this.projParams.b2)/this.projParams.a2;  // e ^ 2
 237               this.projParams.e = Math.sqrt(this.projParams.es);        // eccentricity
 238               if (this.projParams.R_A) {
 239                 this.projParams.a *= 1. - this.projParams.es * (ProjConstants.SIXTH + this.projParams.es * (ProjConstants.RA4 + this.projParams.es * ProjConstants.RA6));
 240                 this.projParams.a2 = this.projParams.a * this.projParams.a;
 241                 this.projParams.b2 = this.projParams.b * this.projParams.b;
 242                 this.projParams.es = 0.;
 243               }
 244               this.projParams.ep2=(this.projParams.a2-this.projParams.b2)/this.projParams.b2; // used in geocentric
 245               if (!this.projParams.k0) this.projParams.k0 = 1.0;    //default value
 246
 247               this.projParams.datum = new Datum(this);
 248                 }
 249
 250                 private function extend(destination:Object, source:Object):void
 251                 {
 252               destination = destination || {};
 253               if(source) {
 254                   for(var property:String in source) {
 255                       var value:Object = source[property];
 256                       if(value != null) {
 257                           destination[property] = value;
 258                       }
 259                   }
 260               }
 261             }
 262
 263                 public function forward(p:ProjPoint):ProjPoint
 264                         {
 265                         if (this.proj!=null)
 266                                 {
 267                                 return this.proj.forward(p);
 268                                 }
 269                         return p;
 270                         }
 271
 272                 public function inverse(p:ProjPoint):ProjPoint
 273                         {
 274                         if (this.proj!=null)
 275                                 {
 276                                 return this.proj.inverse(p);
 277                                 }
 278                         return p;
 279                         }
 280
 281         }
 282 }