Extract Map Attributes
Description
Extracts general attributes and basic statistics from a map, returning them as a lookup table keyed by a predefined attribute code. All layers of the map are analyzed together, and the resulting table refers to them jointly.
Inputs
| Name | Type | Description |
|---|---|---|
| Map | Map Type | Map whose attributes will be extracted. |
Optional Inputs
| Name | Type | Description | Default Value |
|---|---|---|---|
| Extract Dynamic Attributes | Boolean Value Type | If true, dynamic attributes (null/non-null cell counts, minimum, maximum, sum) are also extracted. | Yes |
| Extract Statistical Attributes | Boolean Value Type | If true, statistical attributes (mean, variance, standard deviation, mode, median, unique count) are also extracted. | Yes |
Outputs
| Name | Type | Description |
|---|---|---|
| Attributes | Lookup Table Type | Table of extracted attributes, keyed by attribute code. |
| Layer Attributes | Table Type | Table of per-layer attributes, keyed by layer position in the map. |
Group
Notes
Each attribute has a predefined name that can be used to retrieve it by name (rather than by numeric key) with the tX[“NAME”] syntax in Calculate Map, Calculate Categorical Map, Calculate Value, and the lookup table calculators.
If an attribute cannot be determined, its entry is omitted from Attributes rather than being filled with a placeholder. Minimum and maximum values are only determined when the map has at least one non-null cell.
Basic attributes
| Key | Predefined Name | Description |
|---|---|---|
| 1 | “lines” | number of lines |
| 2 | “columns” | number of columns |
| 3 | “cells” | lines times columns |
| 4 | “layers” | number of layers |
| 5 | “cellHeight” | cell height, in meters |
| 6 | “cellWidth” | cell width, in meters |
| 7 | “cellArea” | cell area, in hectares |
| 19 | “cellType” | cell type code, see Cell type codes below |
| 20 | “nullValue” | null value |
| 21 | “registrationCoordinateY” | registration coordinate Y |
| 22 | “registrationCoordinateX” | registration coordinate X |
| 23 | “registrationCellY” | registration cell Y |
| 24 | “registrationCellX” | registration cell X |
| 25 | “rotationY” | rotation Y |
| 26 | “rotationX” | rotation X |
| 27 | “originalCellHeight” | cell height as specified by the projection |
| 28 | “originalCellWidth” | cell width as specified by the projection |
Dynamic attributes (present only when Extract Dynamic Attributes is true), computed across all non-null cells of all layers:
| Key | Predefined Name | Description |
|---|---|---|
| 8 | “nullCells” | number of null cells |
| 9 | “nonNullCells” | number of non-null cells |
| 10 | “minCell” | minimum value (excluding null cells) |
| 11 | “maxCell” | maximum value (excluding null cells) |
| 12 | “cellSum” | sum of the values (excluding null cells) |
Statistical attributes (present only when Extract Statistical Attributes is true), computed across all non-null cells of all layers:
| Key | Predefined Name | Description |
|---|---|---|
| 13 | “meanCell” | average (excluding null cells) |
| 14 | “cellVar” | variance (excluding null cells) |
| 15 | “cellStd” | standard deviation (excluding null cells) |
| 16 | “modeCell” | mode (excluding null cells) |
| 17 | “medianCell” | median (excluding null cells) |
| 18 | “uniqueCells” | total unique occurrences (excluding null cells) |
Cell type codes used by attribute 19 (“cellType”):
| Code | Cell Type |
|---|---|
| 0 | Unsigned 1 Bit Integer |
| 1 | Signed 8 Bit Integer |
| 2 | Unsigned 8 Bit Integer |
| 3 | Signed 16 Bit Integer |
| 4 | Unsigned 16 Bit Integer |
| 5 | Signed 32 Bit Integer |
| 6 | Unsigned 32 Bit Integer |
| 7 | IEEE 754 32 Bit Real |
| 8 | IEEE 754 64 Bit Real |
Layer Attributes has columns “Layer_Index” (the layer's position) and “Layer_Name” (the layer's name); currently the layer name is the only layer-specific attribute returned.
Internal Name
ExtractMapAttributes
Usage examples
See practical examples of this functor in Lesson 6: Extracting map attributes and basic statistics