Graduated

The Graduated theme annotates themed items by drawing a Symbol, scaled around a value, at the item hook point. The size of the symbols is determined by the values of the item's properties.

Click Home > Add Theme > Annotation and select Graduated.

Click Next to open the Property/Expression dialog.

Use the properties of any class of item to create a Graduated theme. If they are point items, symbols are placed at the point. Else the symbols are placed at the item’s origins.

Click Next.

The Do you want to search the Overlay for existing values? query will be displayed

  • If you check the Scan all available items, without prompting tickbox you will not be asked again during the current session.
  • If you are repeating the process you will be asked Do you want to clear the Theme and search the Overlay for existing values? again you can set to scan all available items, without prompting.

Click Yes to open and edit Graduated Styles.

Option Description
Expresssion

Use Pick Property to choose any of the Built-in Properties or a User-defined atttribute (if any have been defined).

Use the Expression Builder to enter an expression to be evaluated for Items. If using a variable (e.g. _id&, the ID of the Item - every Item is automatically allocated an ID number which is unique within its dataset) the property value is fetched from the Item under consideration.

Settings - For value

Base value around which the Symbol is scaled up or down. With this value, an item is represented by the Symbol at its normal size. If the value is less than this, the Symbol will be smaller; if greater, the Symbol will be bigger.

The chosen graduated by option determines the means of scaling the Symbol.
graduated by

Use the drop-down menu to choose the relevant value:

  • Constant - All Symbols are the same size, i.e. the size of the symbol itself.

  • Square root - The Symbol size is proportional to the square root of the ratio (this is the ratio of the evaluated expression value to the For value).

  • Linear - the Symbol size is proportional to the ratio.

  • Log (base 10) - The Symbol size is: proportional to the log (base 10) of the ratio when the value is greater than or equal to the value given in For value and proportional to the ratio when the value is less than the value given in For value.
Legend samples

Controls the number of legend samples shown in the Legend dialog when the Legend... button is clicked. Possible values in the drop-down are 1, 3, 5, 7, 9.

Styles- Symbol

Selects the symbol that will be used to annotate the themed items. 

Pen/Brush

Selects the pen and brush to be used for annotations.

Filter, Scale and Legend buttons

Note: Click here for Graduated Theme properties.