This is how QGIS writes the proj-string and WKT with +towgs84-parameter:
+proj=longlat +ellps=bessel +towgs84=598.1,73.7,418.2,0.202,0.045,-2.455,6.7 +no_defs
GEOGCS["DHDN",DATUM["Deutsches_Hauptdreiecksnetz",SPHEROID["Bessel 1841",6377397.155,299.1528128,AUTHORITY["EPSG","7004"]],TOWGS84[598.1,73.7,418.2,0.202,0.045,-2.455,6.7],AUTHORITY["EPSG","6314"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4314"]]
But keep in mind that there is no overall value for converting any Bessel-1841-Data to WGS84.
For Germany, there were a lot of parametres published, until a NADgrid for the whole country was created. This applies the correct shift for every point inside Germany.
Other surveying authorities have done similar conversions, but with other values.
EDIT
There is a forum entry in Russian http://gis-lab.info/forum/viewtopic.php?t=9386
giving the following proj parameters:
+proj=tmerc +lat_0=55.6666666667 +lon_0=37.5 +x_0=0 +y_0=0 +k_0=1. +a=6377397 +rf=299.15 +towgs84=396,165,557.7,-0.05,0.04,0.01,0 +no_defs
Maybe you get lucky with those values.
Here's an example that I have of loading geojson from a WFS service: http://maps.gcc.tas.gov.au/dogexerciseareas.html
This is another example loading topojson (similar, but different): http://agl.pw/examples/NRM_Regions/map.html
Here's some simple code I use to load a layer:
var myLayer = L.geoJson().addTo(map);
$.getJSON("data/buildings.json", function(json) {
myLayer.addData(json);
});
Then you can do interactivity and styling with something like this:
success : function (response) {
DogExerciseAreas = L.geoJson(response, {
style: function (feature) {
return {
stroke: false,
fillColor: 'FFFFFF',
fillOpacity: 0
};
},
onEachFeature: function (feature, layer) {
popupOptions = {maxWidth: 200};
layer.bindPopup("<b>Site name:</b> " + feature.properties.sitename +
"<br><b>Dog Exercise: </b>" + feature.properties.dog_exercise +
"<br><br>Please ensure that tidy up after your dog. Dogs must be kept under effective control at all times."
,popupOptions);
}
}).addTo(map);
}
EDIT: an example from the leaflet website on styling points (from here http://leafletjs.com/examples/geojson.html):
var geojsonMarkerOptions = {
radius: 8,
fillColor: "#ff7800",
color: "#000",
weight: 1,
opacity: 1,
fillOpacity: 0.8
};
L.geoJson(someGeojsonFeature, {
pointToLayer: function (feature, latlng) {
return L.circleMarker(latlng, geojsonMarkerOptions);
}
}).addTo(map);
EDIT2: Added a solution to this problem. See here: https://gist.github.com/alexgleith/7112515
All you need to do now is edit the bit where it says 'popupContent' to add your bit and change the code to load data from the file.
Best Answer
You have to add the geojsonLayer to your leaflet map like you did with your tile layer with .addTo(map)