OpenStreetMap Forum

I mean only the IDs, no other information. Because at this web page: http://wiki.openstreetmap.org/wiki/Stats, there is the stat of number of users. Any suggestion?

Many thanks in advance.

Once a feature was created, it could be edited many times. But, in OSM data, there is only one record for one feature, i.e. node, way and relation. Any clues to solve this problem? Many thanks in advance!

Xintao

Hello,

Relations in OSM data could be Multipolygon, which represent different kind of land-uses such as lakes, rivers, forest and so on. The question is: there are not tags inside relations which can be used to identify land-uses. But, obviously, the OSM tiles can tell different land-uses. How do they do it?

Any of your reply is highly appreciated.

Xintao

Hello!

After I download OSM data from CloudMade.com, I use the C# code here (http://wiki.openstreetmap.org/wiki/Mercator#C.23) to transform the longitude and latitude into X and Y coordinates. Then I convert them into ArcGIS shapefile, and use the tool to calculate the area and length. To my big surprise, the results are not correct. For example,  the actual area of Sweden is only 0.45 million square kilometers, while the result is summed to 1.17 million square kilometers.

Am I doing something wrong? Any of your response and comment are highly appreciated.

Thanks.

Xintao

Hello!

I created a vector feature on the map. it appears correctly. The code is showing below:

var style={ externalGraphic: "airplane.gif", graphicWidth: 12,  graphicHeight: 14, fillOpacity: 50 };
style.rotation = Math.floor(Math.random() * 360);
var feature=new OpenLayers.Feature.Vector( new OpenLayers.Geometry.Point(x, y), {angle: planeangle, x_extra: 0, y_extra: 0},style);
vectorLayer.addFeatures([feature]);     //it works fine and appears on the map correctly until here

But then I try to move it to a new place, an error occured.

var planeangle = feature.attributes.angle;
if (planeangle  >= 180) {
   var a = 450-planeangle;
} else {
  var a = 90 - planeangle;
}
var newx = feature.geometry.x - Math.cos(a*Math.PI/180)/10 + feature.attributes.x_extra;
var newy = feature.geometry.y - Math.sin(a*Math.PI/180)/10 + feature.attributes.y_extra;
var newPoint = new OpenLayers.LonLat(newx, newy);
feature.attributes.angle += Math.floor(Math.random()*20);
if(feature.attributes.angle>360){feature.attributes.angle -= 360;}
feature.move(newPoint);

And the error in the IE says: "Message: Arg: Fraction out of range (0 to 1 allowed)"

I have been stucked here for a whole day. I appreciate any of you comments.

Thanks a million.