Example : Working with a WKT Area layer

This example assumes you have successfully embedded the component and validated the license.

This example shows you how to add a polygon layer using WKT data. WKT is a standard for encoding geometries using plain text. The geometries can be expressed in any CRS and can be rendering using a custom legend.

• About WKT Support in WebClient : wkt
• About WKT in General : http://en.wikipedia.org/wiki/Well-known_text

Steps to take :

1. Prepare a Legend
2. Prepare attribute definitions
3. Add a layer
4. Add objects to a layer
5. Remove a layer

var legend = {};
legend.fillColor = "102.0.0";        // default = 0.102.0
legend.fillTransparency = 1.0;       // default = 0.5
legend.lineColor = "255.0.0";        // default = 0.255.0
legend.lineTransparency = 0.2;       // default = 0.0
legend.lineWidth = 3.0;              // default = 1.0

If you want your objects to have certain attributes, they need to be declared when adding the layer. Declaring attributes involves defining a name and type for every attribute :

var attributeDefs = [];
attributeDefs.push({name:"id",type:8/*string*/});
attributeDefs.push({name:"position",type:4/*int*/});

For this example we're using this WKT data :

POLYGON Z ((133837.75075689898 206170.68672386 66.75229158891386, 133837.87326465631 206170.879064952 70.83002653990947, 133838.30827833957 206167.78262598623 70.71889750730033, 133838.25977460685 206167.70199663375 66.79471098851391))

To add a new WKT layer we use the addWKTLayer() function :

var crs = "31370";
 
var legend = {};
legend.fillColor = "255.0.0";          
legend.fillTransparency = 0.5;
legend.lineColor = "255.0.0";         
legend.lineTransparency = 0.2;       
legend.lineWidth = 3.0;              
 
var wktData = "POLYGON Z ((133837.75075689898 206170.68672386 66.75229158891386, 133837.87326465631 206170.879064952 70.83002653990947, 133838.30827833957 206167.78262598623 70.71889750730033, 133838.25977460685 206167.70199663375 66.79471098851391))";
 
var attributeDefs = [];
attributeDefs.push({name:"id",type:4/*int*/});
attributeDefs.push({name:"material",type:8/*string*/});
 
var attributes = new Array();
attributes.push([1,"glass"]);
 
viewer.addWKTLayer("WKT Areas",wktData,"31370"/*crs*/,legend,attributeDefs,attributes);

The last 2 arguments for specifying attribute data are optional and can be ommitted.

As defined in the API Data Types, the available attribute definition types are :

• 8 : <string>
• 4 : <int>
• 6 : <float>
• 1 : <boolean>

New objects can be added to an existing WKT layer. Legend or attribute definitions don't need to be provided because they are already present.

var attributes = new Array();
attributes.push([2,"brick"]);
 
var wktData = "POLYGON Z ((133837.64392282325 206169.81406293903 65.3584886604712, 133838.01128612863 206168.19463629555 65.3584886604712, 133838.0112696399 206168.1946569197 63.59289970688925,  133837.6439063346 206169.81408356223 63.59289970688925))";
 
viewer.addWKTToWKTLayer("WKT Areas",wktData,"31370"/*crs*/,attributes);

When you don't need a layer anymore, you can remove it :

viewer.removeLayer("WKT Areas");