# Summary Processes

The following list describes the types of summarize functions that the Summarize Tool can perform.

Group by: Combines database records with identical values in a specified field into a single record. All of the resulting data from the records in a group are then summarized. (Any non-blob or spatial object has this option.) If no Group by field is specified, the entire file will be summarized.

Sum: Returns the sum value for the group. The sum is calculated by adding all of the values of a group.

Count: Count of records in the group.

Count Non Null: Identical to Count, except it is only counting those records that are NOT null. Null means there is no value set for this record. This is different than a zero or an empty string.

Count Distinct: Count of unique records in the group.

Count Distinct Non Null: Identical to Count Distinct, except it is only counting those records that are NOT null. Null means there is no value set for this record (different than a zero or an empty string)

Min: Returns minimum value.

Max: Returns the maximum value.

First: Returns the first record in the group, based upon its record position.

Last: Returns the last record in the group, based upon its record position.

The following are additional Summary Processes split into categories relevant to the type of field chosen for summarization.

Net Present Value (NPV): Calculates the Net Present Value for a group. Measures the excess or shortfall of cash flows, in present value terms, once financing charges are met. NPV Properties include:

- Discount Rate (Per Period): The discount rate as a percentage. The default value is 8%.

Net Present Value w/ Dates (XNPV): Calculates the Net Present Value for a group for a series of dates. XNPV Properties include:

- Finance Rate: The finance rate as a percentage. The default value is 8%.
- Date Field: The field containing the associated dates.

Internal Rate of Return (IRR): Calculates the Internal Rate of Return for a group. The Internal Rate of Return of an investment is the interest rate at which the costs of the investment lead to the benefits of the investment. This means that all gains from the investment are inherent to the time value of money and that the investment has a zero net present value at this interest rate.

Internal Rate of Return w/ Dates (XIRR): Calculates the Internal Rate of Return for a group for a series of dates. XIRR Properties include:

- Date Field: The field containing the associated dates.

Modified Internal Rate of Return (MIRR): A modification of the internal rate of return and as such aims to resolve some problems with the IRR. The MIRR is a financial measure of an investment's attractiveness. MIRR Properties include:

- Finance Rate: The finance rate as a percentage. The default value is 8%.
- Reinvest Rate: The reinvestment rate as a percentage. The default value is 8% .

Modified Internal Rate of Return w/ Dates (MXIRR): Calculates the Modified Internal Rate of Return for a group for a series of dates. MXIRR Properties include:

- Finance Rate: The finance rate as a percentage. The default value is 8%.
- Reinvest Rate: The reinvestment rate as a percentage. The default value is 8% .
- Date Field: The field containing the associated dates.

*Finance definitions from Wikipedia

Average: Calculates an average value for the group. The average is calculated by taking the sum of all values divided by the total number of values.

Percentile: Calculates the specified percentile value for the group. The percentile is calculated by sorting the data and returning the row value relative to the specified percentile and its position in the sorted array - the largest value is the 100th percentile, lowest value is the 0 percentile, median is the 50th percentile, the 25th percentile is the value in the middle of the median and minimum, etc. Percentile properties include:

- Specify the percentile to return. The default value is 50%.

Median: Calculates the median value for a group. The median of the group is "the number in the middle" when the values are sorted in order. If there is an even number of scores there is no number in the middle so the two numbers in the middle are averaged.

Mode: Calculates the mode value for a group. The mode of a set of numbers is the smallest number that occurs most often in a group of values. If all values are unique, the smallest number will be returned.

Standard Deviation: Calculates the standard deviation for the group. Standard Deviation is a measurement variability used in statistics.

Variance: Calculates the Variance for the group. The variance is calculated by taking the Standard Deviation and multiplying it times itself, StdDev^2.

Ignore 0's: Calculates the Numeric processes described above ignoring records that have a value of zero.

Count Blank: Counts how many records in a group have a blank or empty value.

Count Non Blank: Counts how many records in a group do not have a blank or empty value.

Concatenate: Takes all the records in a group and concatenates the strings. Concatenate Properties include:

- Start: The character specified will appear at the beginning of the concatenated string. It is left blank by default.
- Separator: The character specified will appear in between each value of the concatenated string. The default is a comma ,.
- End: The character specified will appear at the end of the concatenated string. It is left blank by default.

The start, separator and end elements must be specified for each field an action is being applied to. You can enter any character or string, or leave them blank. Supported escape characters include: \n (new line), \t (tab), \r (carriage return), and \s (white space character).

Longest: Returns the longest string value of the group.

Mode: The mode of a set of string values is the smallest string that occurs most often in a group of values. If all values are unique, the smallest string is returned. The smallest string is the first in ascending sort order.

Shortest: Returns the shortest string value of the group.

Combine: Combines the area of all the spatial objects in a group.

Create Intersection: Identifies all of the overlapping areas of a group's spatial objects and creates a polygon that consists only of that overlap. This means that if the group being summarized contains two polygons that overlap and one that does not, nothing will be returned.

Create Bounding Rectangle: Identifies the geographic extent of all spatial objects in a group and draws a bounding rectangle to those extents.

Create Convex Hull: The Convex Hull polygon is the smallest convex polygon that can be drawn to include a group of points. The polygon will not contain any concave angles, so it will never turn in on itself.

Create Centroid: Identifies the geographic center of a group of spatial objects

Combine Profiles: Combines all the Profiles in a group into a single Profile per group specified.

Combine Horizontal: Combines all the Report Snippets in a group into a single snippet for the group laid out horizontally.

Combine Vertical: Combines all the Report Snippets in a group into a single snippet for the group laid out vertically.