Units of measure

Units of measure

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In general, the formulas of cell elements that represent some numeric value (for example, shape position, a dimension, or an angle) require a number-unit pair that consists of a number and the qualifying units needed to interpret the number. In XML for Visio, however, unit information is stored but the value of an element is always expressed in internal units.

For example, values representing units that are a measurement of length are expressed as floating point numbers in inches (internal units). If an element has a value of "2 feet", its Unit attribute is 'FT' for feet and its value is the number 24.

Other units, such as date/time, are expressed as formatted strings. In the case of date/time, it is a string like "2000-12-20T23:00:00".

If a unit of measure is explicitly set, and is different from the default unit for the cell, Microsoft Visio writes out the Unit attribute in XML for Visio files. If no Unit attribute is present in an element that represents a cell, Visio will use the default unit for that element.

For more information about how units of measure work in Visio, see About units of measure in the Microsoft Visio ShapeSheet Reference.

Values of these unit types are expressed as a floating point value in inches (internal units). Therefore, a value of "2 feet" would be expressed as:

  <Width Unit='FT'>24</Width>

A value of "12 Points" would be expressed as:

  <Size>0.16666666666667</Size>

The following tables describe valid units of measure along with information about internal units and how they are expressed in an XML for Visio file.

Note Units of measure that represent an area (acre and hectare) are expressed in square inches.

Angle values are expressed as floating point values in radians (internal units).

Therefore, 180 DEG appears as the following:

  <Angle Unit='DEG'>3.1415926535898</Angle>

Values of this unit type are expressed as a floating point value in elapsed days (internal units). For example, the C element below contains the elapsed days between the dates stored in the A and B elements.

  <A Unit='DATE' F='Date(1969,9,12)'>1969-09-12T00:00:00</A>
<B Unit='DATE' F='Date(1969,9,13)'>1969-09-13T00:00:00</B>
<C Unit='ED' F='Scratch.A1-Scratch.B1'>-1</C>

Values of this unit type are expressed as a string value written out in the ISO 8601 format:

yyyy-mm-ddThh:mm[:ss[.ss]]

The uppercase letter T is a required delimiter between the date portion and the time portion.

The date portion must be complete: four-digit year, a dash, two-digit month, a dash, and a two-digit day.

The time portion must include a two-digit hour, a colon, and a two-digit minute. The time can optionally include another colon and two-digit seconds. After the optional seconds, there can be a dot and followed by digits representing fractional seconds. Fractional seconds can be as precise as nanoseconds.

For example:

  <A Unit='DATE'>2000-09-12T12:34:12.0543</A>

Values of these unit types are expressed as strings. The following table provides an example of each unit type.