Using dimensions

In many areas, reading maps or measurement information on a map is essential. Whether it is a parcel measure, the length of a building or the distance between several elements along a road, GIS users are often faced with this need.

The picture shows an example of using dimensions on a map. As you can see, it indicates on a map the distances between each pipeline inspection chamber. For example, this kind of information can be useful for the Fieldworkers during an intervention but also on the preliminary design analysis of road works.

In this tutorial, you will learn how-to use this kind of geodatabase annotation and how-to layout with ArcGIS Pro.

This tutorial does not go into detail about how to accomplish every single step, but instead gives an overview of the steps you should take. The different screenshots provide hints, but to know further you can use ArcGIS Pro Help.

License:

You can only create dimension feature classes with ArcGIS Desktop Standard and ArcGIS Desktop Advanced licenses.

Step one: Understand Dimensions

Some theorical concepts about the dimension feature are exposed in this first step.

Dimensions are a special kind of geodatabase annotation to show specific lengths or distances on a map. A dimension may indicate the length of a side of a building or land parcel, or the distance between two features, such as a fire hydrant and the corner of a building.

A dimension feature is composed of several parts that may or may not be displayed, depending on the application. These parts are each one represented differently using different symbology and placement rules. The following image is an illustration of the anatomy of a dimension feature:

There are two kind of dimensions feature:

Kind	Picture	Characteristics
Aligned dimension		As the name suggests, aligned dimensions are parallel to the baseline and represent the actual distance between start and end dimension points.
Linear dimension		Linear dimensions do not represent the actual distance between the start and end points. Linear dimensions can be vertical, horizontal, or rotated a)       Vertical = the vertical distance between the start and the end point. b)      Horizontal = the horizontal distance between the start and the end point. c)       Rotated = a dimension whose line shows a certain angle with the baseline and whose length represents the length of the dimension line and not that of the baseline.

Step two: Create a Feature Class “Dimension”

To create a feature class “Dimension”, you can proceed to the same operation than for a feature class “Line” or “Polygon”.

• Go on the Catalog tab and select a geodatabase (gdb) in the location that you want;
• Right- click on the gdb > New > Feature Class

When arriving into the “Create Feature Class” window, be careful on three important steps.

1. Select “Dimension” in the Feature Class Type
2. Choose the coordinate systems for your final map

XY Coordinate Systems:
Changing the coordinate systems of a dimension feature class isn’t possible. A difference of coordinate systems between Dimensions and the other elements on a map can cause big errors in the measures displayed by the dimension. Indeed, the measurements displayed on the dimension is calculated according to the chosen coordinate system.

3. Choose a good reference scale and the right map units

Reference scale:
Changing the reference scale of a dimension feature class is a relatively heavy operation that requires updating the geometry of each feature. When the reference scale is changed, the size of the dimension entities changes, and the quotes may overlap. You should be extremely careful when you modify this property after creating a dimension feature class.

4. Add dimension style to have a specific style according your standards (see step 4: Create a Style).

Step three: Design a Dimension

When your first feature class Dimension is created, you will be able to start drawing your odds on your map.

Be sure that the feature class Dimension is added to the current map. If this not the case, go on the Catalog tab right-click on the Dimension and select “Add to current map” or drop it in the Map Window. I encourage you to do so!