Salesforce provide us standard functionality to create Reports and dashboards to represent record in diagrammatic form. Sometimes we face the requirement to represent our data in diagrammatic Form on visual force page in some specific type of diagram we represent it using chart. Salesforce provide us Bar chart, Pie chart, Gauge chart, Radar charts
Here I am going to explain how we can represent specific field data in the form of gauge chart. To achieve this requirement we need four things basically. First we should have an object whether its standard or custom object, a field associated with that object that should hold any numeric Value, apex controller, apex class.
I will start with object lets say I have a standard controller Account where I have a custom field Score and I need to represent that score in the form of gauge. Whenever page loads that value represent in the form of gauge and whenever the fields value changes the gauge should reflect that Change.