Applies to: Nevron Diagram for .NET (Map for .NET)
How to use range fill rule for coloring Maps in Nevron .NET Diagram?
Fill rules are used to colorize a map based on the values of a shape field. When creating a fill rule you must specify the shapefile it is used on, the fill rule data column name and the colors to use (all of them or only the first, the last and their count). There are two types of fill rules:
- Value fill rules - all unique values in the fill rule’s data column are extracted and each unique value is colorized with the respective color. If the unique values are more than the colors, then the color counting is restarted and some different values will have the same color.
- Range fill rules - these fill rules are only applicable to data columns containing numbers. All unique values in the fill rule’s data column are extracted and then are grouped in a specified number of classes using the grouping algorithm specified to the DataGrouping property.
You can easily create and add fill rules to the FillRules collection of your maps. The following example will help you create a map with a fill rule based on the Japan population per region:
[C#]
using System;
using System.Drawing;
using System.IO;
using System.Windows.Forms;
using Nevron.Diagram;
using Nevron.Diagram.Maps;
using Nevron.GraphicsCore;
...
private void Form1_Load(object sender, EventArgs e)
{
view.ViewLayout = ViewLayout.Fit;
document.Style.FillStyle = new NColorFillStyle(Color.FromArgb(204, 255, 204));
document.Style.StrokeStyle = new NStrokeStyle(new NLength(0.75f, NGraphicsUnit.Point), Color.FromArgb(119, 119, 119));
document.RoutingManager.Enabled = false;
document.BridgeManager.Enabled = false;
document.Bounds = new NRectangleF(0, 0, 2700, 2700);
document.BackgroundStyle.FillStyle = new NColorFillStyle(Color.White);
// create the map
NEsriMap m_Map = new NEsriMap();
// create the COUNTRIES shape file
NEsriShapefile countries = m_Map.Add(SHAPEFILE_NAME);
countries.NameColumn = "GMI_ADMIN";
countries.TextColumn = "ADMIN_NAME";
// read the map data
m_Map.Read();
// create a fill rule
NMapFillRuleRange fillRule = new NMapFillRuleRange(countries, "POP_ADMIN", Color.Green, Color.White, 9);
fillRule.DataGrouping = DataGrouping.Optimal;
m_Map.FillRules.Add(fillRule);
// import the map data
m_Map.Import(document, document.Bounds);
// make the Map layer the active layer so that the user can select the map shapes
string layerName = Path.GetFileNameWithoutExtension(SHAPEFILE_NAME);
NLayer mapLayer = (NLayer)document.Layers.GetChildByName(layerName);
document.ActiveLayerUniqueId = mapLayer.UniqueId;
// size to visible shapes
document.SizeToContent(document.AutoBoundsMinSize, document.AutoBoundsPadding);
}
// select the map shape file
private const string SHAPEFILE_NAME = @" C:\Maps\japan.shp";
[VB.NET]
Imports System
Imports System.Drawing
Imports System.IO
Imports System.Windows.Forms
Imports Nevron.Diagram
Imports Nevron.Diagram.Maps
Imports Nevron.GraphicsCore
...
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
view.ViewLayout = ViewLayout.Fit
document.Style.FillStyle = New NColorFillStyle(Color.FromArgb(204, 255, 204))
document.Style.StrokeStyle = New NStrokeStyle(New NLength(0.75F, NGraphicsUnit.Point), Color.FromArgb(119, 119, 119))
document.RoutingManager.Enabled = False
document.BridgeManager.Enabled = False
document.Bounds = New NRectangleF(0, 0, 2700, 2700)
document.BackgroundStyle.FillStyle = New NColorFillStyle(Color.White)
' create the map
Dim m_Map As New NEsriMap()
' create the COUNTRIES shape file
Dim countries As NEsriShapefile = m_Map.Add(SHAPEFILE_NAME)
countries.NameColumn = "GMI_ADMIN"
countries.TextColumn = "ADMIN_NAME"
' read the map data
m_Map.Read()
' create a fill rule
Dim fillRule As New NMapFillRuleRange(countries, "POP_ADMIN", Color.Green, Color.White, 9)
fillRule.DataGrouping = DataGrouping.Optimal
m_Map.FillRules.Add(fillRule)
' import the map data
m_Map.Import(document, document.Bounds)
' make the Map layer the active layer so that the user can select the map shapes
Dim layerName As String = Path.GetFileNameWithoutExtension(SHAPEFILE_NAME)
Dim mapLayer As NLayer = DirectCast(document.Layers.GetChildByName(layerName), NLayer)
document.ActiveLayerUniqueId = mapLayer.UniqueId
' size to visible shapes
document.SizeToContent(document.AutoBoundsMinSize, document.AutoBoundsPadding)
End Sub
' select the map shape file
Private Const SHAPEFILE_NAME As String = "C:\Maps\japan.shp"
The different data grouping methods are:
- Equal Distribution - also known as quantiles, this method allows for unequally sized data intervals and involves adjustment of the interval limits until an equal number of data points can be slotted into each interval.
- Equal Interval - also known as equal ranges (or steps), this method involves division of the entire data range into equally sized intervals.
- Optimal - adjusts the size of data intervals in order to minimize the classification error and thus the map looks more balanced and the results seem more correct, with just a few shapes in the highest class as one would expect.
Article ID: 169, Created On: 1/10/2011, Modified: 1/10/2011