Can't use specific projection with OpenLayers

Question

I'd like to use specific projection with OpenLayers. I linked proj4js with my html

<html>
  <head>
    <title>OpenLayers Test</title>
    <style type="text/css">
            #map {
                width: 600px;
                height: 300px;
                border: 1px solid black;
                float:left;
            }
        </style>
    <script type="text/javascript" src="http://svn.osgeo.org/metacrs/proj4js/trunk/lib/proj4js-compressed.js"></script>
    <script type="text/javascript" src="OpenLayers.js"></script>
    <script type="text/javascript" src="code.js"></script>
    <link rel="stylesheet" href="http://openlayers.org/dev/theme/default/style.css" type="text/css">
  </head>

  <body onload="init()">
    <div id=map>
    </div>
    <div id=map_coord></div>
    <div id=lonlat></div>
  </body>
</html>

and added new projection:

Proj4js.defs["EPSG:987654"] = "+proj=eqdc +lat_1=46.4 +lat_2=71.8 +lon_0=100 +ellps=krass +units=m +no_defs";

But reprojection doesn't work, I get NaN values. Here is code.js:

Proj4js.defs["EPSG:987654"] = "+proj=eqdc +lat_1=46.4 +lat_2=71.8 +lon_0=100 +ellps=krass +units=m +no_defs";

var map;

OpenLayers.Control.Click = OpenLayers.Class(OpenLayers.Control, {
    defaultHandlerOptions: {
    'single': true,
    'double': false,
    'pixelTolerance': 0,
    'stopSingle': false,
    'stopDouble': false
    },

    initialize: function(options) {
        this.handlerOptions = OpenLayers.Util.extend(
            {}, this.defaultHandlerOptions
        );
        OpenLayers.Control.prototype.initialize.apply(
            this, arguments
        );

        this.handler = new OpenLayers.Handler.Click(
            this, {
                'click': this.trigger
            }, this.handlerOptions
        );
     },

    trigger: function(e) {
        var mapcoord = map.getLonLatFromPixel(e.xy);
        mapcoord.transform(new OpenLayers.Projection("EPSG:4326"), new OpenLayers.Projection("EPSG:987654"));
        alert(mapcoord);
   }

});

function init()
{

    map = new OpenLayers.Map('map',
        {
            controls: [
              new OpenLayers.Control.MousePosition ({
                div: document.getElementById("map_coord")
              }),
              new OpenLayers.Control.MousePosition ({
                div: document.getElementById("lonlat"),
                displayProjection: new OpenLayers.Projection('EPSG:4326')
              })
            ],
            units: "m",
            projection: "EPSG:987654",
            maxExtent: new OpenLayers.Bounds(-5000000, 4400000, 4000000, 10000000)
        }
    );

    var ltopo = new OpenLayers.Layer.WMS("topo", "http://ows.mgs.geosys.ru/topo/base",
            { layers: "topo_land,world_ocean,topo_base,elev,vegt,lcov,phys,bath,hyps,dnet_pg,pplc_pg,dnet_pt,hydr,clmk,infr"}
        );

   map.addLayers([ltopo]);
   var click = new OpenLayers.Control.Click();
   map.addControl(click);
   click.activate();

   map.zoomTo(3);
}

That is a projection you have created, no? Could you maybe add a couple of coordinate pairs of source and destination (4326) and what you expect to see, so we could try it with proj4js, which is where I suspect the problem might be. — John Powell, Jul 21 '14 at 12:24
-4481368.53 6317117.12 43d19'0.902"E 38d55'35.034"N -5724363.14 5844144.14 38d54'46.852"E 27d35'9.783"N — Alexander Popov, Jul 21 '14 at 12:43
The transform method is tranfrom(from, to, method) and you have EPSG:987654 as your maps projection, so I think the line that does the transfrom should be this way round: mapcoord.transform(new OpenLayers.Projection("EPSG:987654"), new OpenLayers.Projection("EPSG:4326")); It is still broken, but am I correct? — John Powell, Jul 21 '14 at 16:30
Yes, you are right, I mixed up source and destination projections in transform method call. But it still doesn't work, returns (NaN, NaN). So it seems the error in proj4js. — Alexander Popov, Jul 22 '14 at 08:04
Yes, I don't think it has anything to do with OpenLayers. It would be easier to debug directly in proj4js, which is why I asked for sample points and expected output. — John Powell, Jul 22 '14 at 08:09

score 0 · Answer 1 · answered Jul 22 '14 at 09:54

The problem has been resolved. I was given with bad projection string (some parameters were missed). Instead of using

+proj=eqdc +lat_1=46.4 +lat_2=71.8 +lon_0=100 +ellps=krass +units=m +no_defs

I should have used

+proj=eqdc +lon_0=100 +lat_0=0 +x_0=0 +y_0=0 +lat_1=46.4 +lat_2=71.8 +towgs84=0,0,0,0,0,0,0 +ellps=krass +units=m +no_defs

But it is curious that C version of Proj4 works perfectly with the fist string also.

Thanks to John Barça for help.

Can't use specific projection with OpenLayers

1 Answers1