Append Data expressions

Expressions are used in the Append Data tool to calculate input layer fields using append layer field values. When you're not appending fields from the append layer, use expressions to determine how each feature will be populated. An Append Data expression should result in values of the same type as the field. Expression examples are included in the following sections.

The Append Data tool was introduced at 10.6.1 and can use Arcade expressions to append field values. Using Arcade, field names are formatted as $feature["field name"] or $feature.fieldname. The first option, $feature["field name"], is required when a field name includes a space. All examples below use this option.

Learn more about Arcade expressions

The following tools use Arcade expressions in GeoAnalytics Server:

• Reconstruct Tracks to buffer expressions
• Create Buffers to buffer expressions
• Join Features to join expressions
• Detect Incidents to detect incidents using start and end expressions
• Calculate Field to calculate field values

Mathematical operation and function examples

Expressions can mathematically process numbers. The following table shows a sample of available operations.

Learn more about mathematical operations and functions in Arcade

Operator	Explanation	Example	Result
a + b	Returns the sum of a plus b.	fieldname contains a value of 1.5 $feature["fieldname"] + 2.5	4.0
a - b	Returns the difference of a minus b.	fieldname contains a value of 3.3 $feature["fieldname"]- 2.2	1.1
a * b	Returns the product of a times b.	fieldname contains a value of 2.0 $feature["fieldname"] * 2.2	4.4
a / b	Returns the quotient of a divided by b.	fieldname contains a value of 4.0 $feature["fieldname"] / 1.25	3.2
abs( a )	Returns the absolute (positive) value of a.	fieldname contains a value of -1.5 abs($feature["fieldname"])	1.5
log ( a )	Returns the natural logarithm (base E) of a.	fieldname contains a value of 1 log($feature["fieldname"])	0
sin ( a )	Returns the trigonometric sine of a. The input is assumed to be an angle in radians.	fieldname contains a value of 1.5707 sin($feature["fieldname"])	1
cos( a )	Returns the trigonometric cosine of a. The input is assumed to be an angle in radians.	fieldname contains a value of 0 cos($feature["fieldname"])	1
tan( a )	Returns the tangent of a. The input is assumed to be an angle in radians.	fieldname contains a value of 0 tan($feature["fieldname"])	0
sqrt( a )	Returns the square root of a.	fieldname contains a value of 9 sqrt($feature["fieldname"])	3
min( a, b )	Returns the lowest valued number between a and b.	fieldname contains a value of 1.5, and a value of -3 min($feature["fieldname"], -3)	-3
max( a, b )	Returns the highest valued number between a or b.	fieldname1 contains a value of 1.5, and fieldname2 contains a value of -3 max($feature["fieldname1"], $feature["fieldname2"])	1.5
constrain(<value>,<low>,<high>)	Returns the input value if it's within the constraining bounds. If the value is less than the low value, it returns the low value. If the value is greater than the high value, it returns the high value.	constrain( $feature["distance"], 0, 10) constrain($feature['Store dist'], 6, distance)	Returns 0 if distance is less than 0, 10 if distance is greater than 10, and distance otherwise. Returns 6 if Store dist is less than 6, distance if Store dist is greater than distance, and Store dist otherwise.

Text function examples

Append Data expressions can process text. The following table shows a sample of available operations.

Learn more about text functions in Arcade

Operator	Explanation	Example	Result
concatenate( <values>, <separator>)	Concatenates values together and returns a string. values—An array of string values to concatenate. separator ( optional)—A separator to use for concatenation if the values parameter is an array, or a string to concatenate if a single value is provided for the first parameter. If not provided, it will be empty.	fieldname contains a value of GeoAnalytics Concatenate ([$features["fieldname"], "is", "great!"], ' ')	GeoAnalytics is great!
find(<searchText>, <text>, <startPos>)	Finds a string within a string. Wildcards are not supported. searchText—The substring to search for. text—The text to search. startPos (optional)—The zero-based index of the location in the string to search from.	fieldname1 contains a value of 14NorthStreet and fieldname2 contains a value of North find($feature["fieldname2"], $feature["fieldname1"])	2
lower(<value>)	Makes a string lowercase. value—The string to be made lowercase.	fieldname contains a value of GEOANALYTICS lower($feature["fieldname"])	geoanalytics

Text example using find and lower.

find(("north"), lower("146NorthStreet"))

Date function examples

Append Data expressions can process dates. The following table shows a sample of available operations. In Arcade, month values range from 0 (January) to 11 (December), day values from the 1st to the 31st, hour values from 0 (12:00 a.m.) to 23 (11:00 p.m.), minute and second values from 0 to 59, and millisecond values from 0 to 999. Arcade dates return time values in the location of your GeoAnalytics Server.

Learn more about date functions in Arcade

Operator	Explanation	Example	Result
date( <value>, <month>, <day>, <hour>, <minute>)	Parses a value or set of values into a date string. value(optional)— Either the number of milliseconds since January 1, 1970 UTC or a number representing a year. If a year is specified, the month and day must also be provided in subsequent parameters. This value can also be a date string or an ISO 8601 string to be converted into a date. month (optional)—The month (0-11) where 0 is January and 11 is December. day (optional)—The day of the month (1-31). hour (optional)—The hour of the day (0-23). minute (optional)—The minute of the hour (0-59). second (optional)—The second of the minute (0-59). millisecond (optional)—The millisecond of the second (0-999).	fieldname contains a value of 1476987783555 Example 1: Date($features["fieldname"]) Example 2: Date(2017,0,14,0) Example 3: Date()	Example 1: 20 Oct 2016 11:23:03 am Example 2: 14 Jan 2017 12:00:00 am Example 3: Returns the current time
DateDiff(<date1>, <date2>, <units>)	Subtracts two dates and returns the difference in the specified units. date1—The date value from which to subtract a second date. date2—The date value to subtract from the first given date. startpos (optional)— The units used to return the difference of the two given dates. The supported unit types are milliseconds, seconds, minutes, hours, days, months, and years. The default value is milliseconds.	Example 1: DateDiff(Date(2017,1,14,0), Date()) Example 2: DateDiff(Date(2017,1,14,0), Date(), "Years")	Result will vary depending on when you run this command. Example 1: -20532129137 Example 2: -0.6546783768647119
Year(<dateValue>)	Returns the year of the given date. value—A date value identifying the year.	Example 1: fieldname is a field of type Date with a value of 09 Oct 2017 04:30:43 pm Year($feature["fieldname"]) Example 2: fieldname is a string field formatted as an ISO 8601 string with a value of 2012-09-27	Example 1: 2017 Example 2: 2012

Logical function examples

In addition to simple mathematical expressions, more advanced functions can be used to apply buffer expressions.

Function	Explanation	Example	Result
iif(<condition>,<true value>,<false value>)	Returns one value if a condition evaluates to true and returns another value if that condition evaluates to false. <true value> and <false value> can be the following: A numeric field. If there is a space in the field name, use square brackets. A number. A function.	iif($feature["field1"] > $feature["field2"], $feature["field1"], 0) iif($feature["field1"] > $feature["field2"], iif($feature["field2"] = 0, $feature["field3"], $feature["field4"]), 0)	Returns field1 if field1 is greater than field2, and 0 otherwise. Returns the result of the second iif function if field1 is greater than field2, and 0 otherwise.
when(<expression1> , <result1> , <expression2> , <result2> , ... , <expressionN> , <resultN>, <default>)	Evaluates a series of expressions in order until one evaluates to true. expression—An expression. result—The result of the expression. It can be a number or field. default—An optional value if none of the expressions match.	when(($feature["field1"] + 10) > 1, 1,($feature["field2"] + 10) > 2 , 2, $feature["field3"])	If field1 + 10 is greater than 1, returns 1. If not, checks if field2 + 10 is greater than 2. If yes, it returns 2. If not, it returns field3.
decode(<conditional val> , <case1> , <result1>, <case2>, <result2>, ... <caseN>, <resultN>, <defaultValue> )	Evaluates an expression and compares its value with subsequent parameters. If the expression matches, it returns the next parameter value. If none match, there is the option for the last parameter to be a default return value. conditional val—The conditional value. It can be a field or an expression. case—A value to be compared to the conditional val. result—The result if the corresponding case matches the conditional val. defaultValue—An optional value if no other values are true.	decode($feature["field1"] + 3 , $feature["field1"], 1, $feature["field2"], 2, 0)	Compares equality between the conditional val field1 + 3 and case1 field1. If true, it returns 1. If false, it compares the equality between field1 + 3 and field2. If true, it returns 2; otherwise, it returns 0.

Conditional operators

Conditional statements can use the following operators:

Operator	Explanation	Example	Results
a > b a < b	a is greater than b a is less than b	10 > 2	False
a >= b a <= b	a is greater than or equal to b a is less than or equal to b	abs(-10) >= 10	True
a != b	a is not equal to b	abs(-3) != -3	True
a == b	a is equal to b	abs(-5) == 5	True
<condition1> || <condition2>	Condition 1 or condition 2 is met.	(abs(-5) == 5) || (10 < 2)	True
<condition1> && <condition2>	Condition 1 and condition 2 are met.	(abs(-5) == 5) && (10 < 2)	False