Transform Options

The Transform Options dialog becomes available in the Transform panel when the action button is set to Add Component, as some transform templates allow.  Templates which do not allow changing the action button from Update Field  to Add Component do not use Transform options.    Transform options control how fields from the target and overlay drawings are brought into the resulting modified target drawing.

 

il_overlay_process.png

 

Transform options allow specifying:

 

 

The Transform Options dialog appears when the Options button is pressed in the Transform panel.

 

eg_transfer_options_methods01_00.png

 

The most common use of the Transform Options dialog is with Overlay and Overlay Topology templates, to specify how fields from the overlay drawing will be transferred to the new, modified target drawing that is created by the template.

 

To use the Transform Options dialog:

 

  1. With the focus on the target drawing, in the Contents pane click on the Transform pane.

  2. Choose the desired template and the desired overlay or other accessory drawing.

  3. Change the action button to Add Component.

  4. Press the Options button.

  5. If desired, change the suggested names for the components to be created.

  6. Click on a field to highlight it.   Ctrl-click to highlight more than one field.

  7. Choose the Transfer method to apply to the highlighted fields.  ignore means to not transfer the field.

  8. Press OK.

  9. Back in the Transform panel press Add Component to create the new component using those Transfer options.

 

Overview

il_transfer_options.png

Controls

Table

The name to use for the new, modified target table that is created.   A default suggestion is offered.  Editing that default suggestion will cause the paired Component below to also alter in a similar manner.

Component

The name of the component, usually a drawing, which visualizes the new Table.  May be edited as desired.

(Fields pane)

Provides a list of all fields both in the target drawing and in the overlay drawing including the data type of each field and the transfer method to be used. A blank transfer method indicates the field will not be transferred into the resulting new table.   Icons next to each field provide a visual cue as to the source and aggregation status.

i_icon_transfer_options_target_field.png

A field in the target drawing.

i_icon_transfer_options_target_field_aggregate.png

A field in the target drawing that is aggregated from multiple values into one, for example, during a Union Areas template operation.

i_icon_transfer_options_overlay_field.png

A field in the overlay or other participating drawing.

i_icon_transfer_options_overlay_field_aggregate.png

A field in the overlay or other participating drawing that is aggregated from multiple values into one, for example, during an Overlay Contained template operation.

Transfer

Choose the aggregation method to be used.  Becomes active when one or more fields is highlighted.   Click on a field to highlight it.  Ctrl-click to highlight more than one field.

 

The method chosen in the Transfer box applies to all fields that are highlighted.  Methods other than transfer, ignore and copy are available only for some data types, such as numeric types.

 

transfer

Transfer the field value as is with no aggregation.  

ignore

Do not transfer the field.  If ignore is chosen the transfer method displayed in the fields pane for that field will be blank.

copy

Copy the value of the field into the new table.   If more than one record is being aggregated, copy the value of the field for the first record encountered.

average

Transfer into this field in the new table the average of values found in this field in aggregated records.

count

Transfer into this field in the new table the total number of aggregated records.

max

Transfer into this field in the new table the maximum value found in this field in aggregated records.

median

Transfer into this field in the new table the median of values found in this field in aggregated records.

min

Transfer into this field in the new table the minimum value found in this field in aggregated records.

stdev

Transfer into this field in the new table the standard deviation of values found in this field in aggregated records.

stdevpop

Transfer into this field in the new table the standard deviation of values found in this field in the entire table.   The method name is a mnemonic for the standard deviation for an entire population.

sum

Transfer into this field in the new table the sum of values found in this field in aggregated records.

var

Transfer into this field in the new table the variance of values found in this field in aggregated records.  

varpop

Transfer into this field in the new table the variance of values found in this field in the entire table.   The method name is a mnemonic for the variance for an entire population.

Examples

Consider a map with two drawing layers, a Cities layer that shows cities as points and a Centre layer that shows the region of Centre in France as an area.

eg_transfer_options_methods01_01.png

In the Cities Table each record for a city has a name for the city as well as a Pop population value.

 

eg_transfer_options_methods01_02.png

The Centre Table has only the geometry field for the area and a Region field with the name of the region.

eg_transfer_options_methods01_03.png

 

We will use the Overlay Contained template to transfer the several population values from the Cities points records into a single population value for the Centre record.   We will repeat this process using all twelve of the transferring methods to illustrate how each method works.

 

We click on the Centre layer tab in the map to make Centre the active drawing and then in the Contents pane we click on the Transform pane.

 

eg_transfer_options_methods01_04.png

 

We set Geom as the target field and then we choose the Overlay Contained template, which takes field values from all objects Contained by Centre and choose Cities as the Overlay drawing.   

 

eg_transfer_options_methods01_04a.png

 

As soon as we choose the Overlay Contained template, the map window shows a preview of the Centre region in blue, indicating it will be the object affected by the template.   In the Transform panel we press Options to open the Transform Options dialog.

 

Our first step is to specify a short name for the resulting component that includes Copy in its name, so that when we open the resulting table we will know at a glance from the name of the table what transfer method was used to transfer the population field.

 

eg_transfer_options_methods01_05a.png

 

We click the mfd_id, City and Geom fields to highlight them and then we choose ignore for the Transfer method so those fields will not be transferred.  

 

eg_transfer_options_methods01_05.png

 

Next, we click on Pop to highlight the population value field and we choose copy as the Transfer method.   We press OK and then back in the Transform panel we press Add Component to create a new table and drawing that include a Pop field brought over using the copy method.

 

In the illustrations that follow we will show the original Cities table along with the table created by the transform.

Copy

eg_transfer_options_methods01_02.pngeg_transfer_options_methods01_06.png

When multiple records are involved in an aggregate the copy method copies the value of the first record.   All of the points in the Cities table are contained by the one area in the Centre table (all are cities within the Centre region of France) so there are multiple records that are aggregated by the Overlay Contained template.   Copy takes the value of the first record, for the city of Avord with a population of 2100, and places that record into the new o_Pop field in the newly created record.  The new field is named by default by prefixing o_ to the name, Pop, of the field that was transferred.

Average

We continue the examples by once again clicking Options to change the Transfer Options dialog settings.  We will change the name of the components to be created to include the word Average.

 

eg_transfer_options_methods01_07.png

 

With the Pop field highlighted we change the Transfer method to average.  We press OK and then back in the Transfer panel we press Add Component to create a new table and drawing that include a Pop field brought over using the average method.

 

eg_transfer_options_methods01_02.pngeg_transfer_options_methods01_08.png

 

The average method finds the average value of the Pop values for the records that are contained within Centre and places that average value into the new o_Pop field.

 

With the remaining transfer methods in this example to save space we will not illustrate the Transfer Options dialog as we choose a transfer method for the Pop field and also change the name of the components to be created to reflect the name of the transfer method.

Count

eg_transfer_options_methods01_02.pngeg_transfer_options_methods01_10.png

The count method adds up the total number of records in the aggregate and places that sum into the new record.  There are nine records in the aggregate so the value 9 is placed into the resulting o_Pop field.   This is a case where the first thing we might do with the new table is to rename the field into some name meaning number of cities in the region.

Max

eg_transfer_options_methods01_02.pngeg_transfer_options_methods01_12.png

 

The maximum method scans all values in the field for records in the aggregate to find the maximum value and puts that into the new field.   Within the Pop values in the Cities Table the maximum population is for the city of Tours, at 129500, so the value of 129500 is placed in the new o_Pop field.

Median

eg_transfer_options_methods01_02.pngeg_transfer_options_methods01_14.png

 

The median method computes the median value for the nine values of population in the records that are aggregated and puts that value, 51000, into the o_Pop field.   The median of the nine values is 51000, the population of Chateauroux, because there are four records with populations lower than 51000 and four records with populations higher than 51000.

Min

eg_transfer_options_methods01_02.pngeg_transfer_options_methods01_16.png

The minimum method scans all values in the field for records in the aggregate to find the minimum value and puts that into the new field.   Within the Pop values in the Cities Table the minimum population is for the city of Avord, at 2100, so the value of 2100 is placed in the new o_Pop field.

Stdev

eg_transfer_options_methods01_02.pngeg_transfer_options_methods01_18.png

 

The stdev method computes the standard deviation for the nine values of population in the records that are aggregated, using n-1, that is 8, as the sample size and puts that value, 43770, into the o_Pop field.

Stdevpop

eg_transfer_options_methods01_02.pngeg_transfer_options_methods01_20.png

 

The stdevpop method computes the standard deviation for the nine values of population in the records that are aggregated, using n, that is 9, as the sample size and puts that value, 41267, into the o_Pop field.

Sum

The sum method computes the sum of the nine values of population in the records that are aggregated and puts that value, 495737, into the o_Pop field.

 

eg_transfer_options_methods01_02.pngeg_transfer_options_methods01_22.png

Var

The var method computes the variance for the nine values of population in the records that are aggregated, using n-1, that is 8, as the sample size and puts that value, 1702979757, into the o_Pop field.  and puts that value, 1915852227, into the o_Pop field.

 

eg_transfer_options_methods01_02.pngeg_transfer_options_methods01_24.png

Varpop

The varpop method computes the variance for the nine values of population in the records that are aggregated, using n, that is 9, as the sample size and puts that value, 1702979757, into the o_Pop field.

 

eg_transfer_options_methods01_02.pngeg_transfer_options_methods01_26.png

 

Notes

The illustrations in this topic use data from a US military site.  The selection of cities shown within the region of Centre were part of a military data set where important facilities such as military airports were located.  The selection of cities does not represent the most important or largest cities or other criteria, nor are population values up to date.   The cities serve in this example simply as a sample  of points with populations that can be transferred to show how different transfer methods work.

 

See Also

Contents Pane

 

Transform

 

Contents - Transform

 

Transform Templates

 

Transform Templates - Drawings

 

Transform Templates - Geom

 

Transform: Overlay

 

Transform: Overlay Topology

 

Example: Overlay Contained -  A frequent use of overlays is to sum the values of many points that fall within an area and to transfer that sum to a new field for an area.  In this example we take a drawing that has cities in the US with a population value for each city.  We use Overlay Contained  to sum the population of each city within a state and to transfer that sum to a total population for the state.

 

Example: Overlay Containing - One of the most common uses of overlays is to transfer fields from areas to points that are contained in those areas.    Tasks such as transferring a census block group number or zip code number from a drawing of areas to points that fall within each area are extremely common.   In this example we transfer the name of a French region  to the points that represent cities which fall within each region.

 

Example: Overlay Topology Intersect - In this example we use the Overlay Topology, Intersect template in the Transform panel  to trim a drawing of points so that all points which do not fall within areas in a second drawing are deleted.   The drawing of points we trim will become the US cities drawing that is used in the Example: Overlay Contained topic.

 

Example: Transfer Options and Merge Areas - Using the Merge Areas Transform panel  template, an exploration of the difference between using Copy and Sum for transfer options.

 

Example: Union Areas - Combine multiple area objects into a single area.   A drawing of French regions shows some regions as more than one area.  We would like each region to be one area so the table of regions has one record per region.