Introduction in the concept of FAO Land Cover Classification System

Compiled by

Sergey BARTALEV

from Louisa J.M. Jansen and Antonio Di Gregorio

METIER Graduate Training CourseRemote Sensing of the Land Surface23-27 April 2007, University of Leicester, UK

Difference between Classification and Legend -1-Classification is defined as the “ordering or arrangement of ordering or arrangement of objects into groups or sets on the basis of their relationshipsobjects into groups or sets on the basis of their relationships”(Sokal, 1974). It is an abstract representation of the situation in the field, using well-defined diagnostic criteria.

Classification Concepts

Abstract representation of a classification consisting of a continuum with two gradients: circles and triangles in red and white (Küchler and Zonneveld, 1988).

Concrete situation in the field in a particular area (Küchler and Zonneveld, 1988). One should note that not all possible combinations of circles and triangles occur.

Difference between Classification and Legend -2-Legend is defined as the “application of a classification in a application of a classification in a particular geographic area particular geographic area ” (Di Gregorio and Jansen, 1998).

Classification Concepts

100%

50%

10%

>50m 30m >5m1 2 3 4 ...

97 9899100

3347

7883

Reference Classification System

DEFINEDGEOGRAPHIC

AREA

given scale and data type

mappingunits

derivedlegend

A priori versus a posterioriclassification

Classification Concepts

CONCRETE FIELD SITUATIONA PRIORI CLASSIFICATION

A POSTERIORI CLASSIFICATION

ADVANTAGES:

- HIERARCHICAL ORDER- STANDARDIZATION

DISADVANTAGES:

- IMPLICIT RIGIDITY OF THE SYSTEM

ADVANTAGE:

- HIGH DEGREE OF FLEXIBILITY

DISADVANTAGES:- DEPENDING ON AREA- NO STANDARDIZATION

OR HIERARCHICAL ORDER

Example of a very general a priori a priori classificationclassificationbased on four classes (triangle in black and white

and circle in black and white) representing the field situation below.

Due to the generalization of the classes, the user is obliged to make the best fit of one of the hundred

possibilities in the field into one of the four classes, which may result in selecting a class that does not

represent well the actual situation.

Example of a a posterioriposteriori classificationclassification. The classes fit better the actual situation

in the field (the area inside the blue rectangle) but the area described is only

a portion of the total.

Underlying Principle

Conceptual Basis

cover

height

100%

50%

10%

>50m 30m >5m1 2 3 4 ...

97 98 99 100

leaf type

leaf phenologyevergreen deciduousmixed

broadleaved(very large)

broadleaved(very small)

aphyllous

needleleaved

natural vegetationnatural vegetation1 2 3 4 ...

25specific

geographicarea

Example of description of a land cover using two different

underlying principles.

The outcome depends on the underlying principle

adopted.

Current a priori classifications in relation to flexibility

Conceptual Basis

high level of standardization

lowflexibility

incr

easi

ng n

umbe

r of c

lass

es

understandable list of class names

enormous list ofclass names with

unclear or too narrowclass boundary

limited number ofgeneric classes

limited number ofgeneric classes

adequate numberof detailed classes

high flexibility

low level of standardization

By increasing the number of classes in an a priori system, flexibility will increase.

Class boundary definitions are based on very slight differences; this will decrease the level of standardization.

Class boundary definitions will be clear and classes will contain aggregated land cover types. However, it has low flexibility.

Flexibility that will allow the accommodation of any occurring land cover.

New approach to classification -1-Increasing flexibility while maintaining mapabilitymapabilityThe classification should be flexible in the sense that it should address the potential for the classification system to describe enough classes to cope with the real world.

At the same time flexibility should adhere to strict class boundary definitions that are unambiguous and clear.

Basic principle

A land cover class is defined by the combination of a set of independent diagnostic attributes, the so-called classifiersclassifiers, that are arranged to assure a high degree of mapabilitymapability, i.e., geographical accuracy.

Conceptual Basis

New approach to classification -2-Issues impeding application of the new approach

Land cover deals with a heterogeneous set of classes. Therefore one single set of classifiers cannot be used to describe all features.

The set of classifiers is tailored to each major land cover feature in order to create meaningful combinations of classifiers.

Furthermore, with the aim of achieving a logical and functional hierarchical arrangement of classifiers, certain design criteriadesign criteriahave been applied.

Conceptual Basis

The initial Dichotomous Phase Dichotomous Phase of LCCS

Conceptual Basis

The subsequent ModularModular--Hierarchical PhaseHierarchical Phase of LCCS

Conceptual Basis

The sets of classifiers tailored to the major land cover and hierarchically arranged according to mapability (classifiers presented in dark blue).

The ModularModular--Hierarchical PhaseHierarchical Phase of two major land cover types in detail

Conceptual Basis

The set of land cover classifierstailored to the major land cover and hierarchically arranged according to mapability.

The environmental attributes that influence the land cover.

The specific technical attributes.

A11. Cultivated and Managed Terrestrial Areas

A12. Natural and Semi-Natural Terrestrial Vegetation

Concept for creation of a land cover classStepwise selection of classifiers that will generate:

• a string of codes, the so-called Boolean FormulaBoolean Formula;

• a Standard Class NameStandard Class Name; and

• a unique Numerical CodeNumerical Code.

Conceptual Basis

Example “Natural and Semi-Natural Terrestrial Vegetation (A12)”Example “Natural and Semi-Natural Terrestrial Vegetation (A12)”Example “Natural and Semi-Natural Terrestrial Vegetation (A12)” :

Classifiers Used:Classifiers Used:Classifiers Used: Boolean Formula:Boolean Formula:Boolean Formula: Standard Class Name:Standard Class Name:Standard Class Name: Code:Code:Code:Code:Life Form & Cover A3A10 Closed Forest 20005Height A3A10B2 High Closed Forest 20006 Spatial Distribution A3A10B2C1 Continuous Closed Forest 20007Leaf Type A3A10B2C1D1 Broadleaved Closed Forest 20095Leaf Phenology A3A10B2C1D1E2 Broadleaved Deciduous Forest 200972nd Layer: LF, C, H A3A10B2C1D1E2F2F5F7G2 Multi-Layered Broadleaved

Deciduous Forest 206283rd Layer: LF, C, H A3A10B2C1D1E2F2F5F7G2 Multi-Layered Broadleaved Deciduous

F2F5F10G2 Forest With Emergents 20630

With each classifier option selected, the string of codes grows, the class name

changes and so does the code.

Conceptual Basis

How to create Land Cover Classes in LCCS? -1-

The same is true for LCCS, the user has to find the correct combination of classifiers to describe a certain land cover feature.

As with using a language, all the concepts exist. The problem is to find the right combination of words to describe things.

No preNo pre--defined list exists. The user has to create defined list exists. The user has to create --one by oneone by one--each single class needed. This involves a process of passing froeach single class needed. This involves a process of passing from m

the userthe user’’s idea of the class, to the creation of the s idea of the class, to the creation of the representation of this idea using a meaningful sequence of representation of this idea using a meaningful sequence of

classifiers that are able to precisely illustrate this idea of tclassifiers that are able to precisely illustrate this idea of the he specific land cover feature.specific land cover feature.

Conceptual Basis

How to create Land Cover classes in LCCS? -2-

Basic concept of a land cover class(the idea)the idea)

Use of LCCS method(the language)(the language)

Elaboration of the conceptin the codifiedLCCS language

(the concept expression)(the concept expression)

Trees A3Closed A10

Height 14-7m B6Needeleaved D2

Evergreen E1

=A3+A10+B6+D2+E1

trees

closedopen

shrubsherbaceous

sparse

evergreenbroadleaved?

??

Conceptual Basis

LCCS is a concise language, it uses the minimum set of classifiers to characterize a land cover feature.

WHY? For three main reasons:

1. there is a difference between the processes of classifying and describing a feature;

2. use of the minimum set of classifiers necessary reduces interpretative errors and facilitates homogeneity in interpretation; and

3. characterization of a land cover feature with a minimum set of classifiers will reduce and simplify field verification.

Conceptual Basis

For Example:If an elephant needs to be described, all the possible features may be used:

Big earsTusks

Trunk

Big feetGrey skin

Higher than 2.5 m

If an elephant needs to be classified, only a few elements should be used, i.e., those that allow a clear identification:

TusksTrunk

All other attributes of the elephant can be linked in the database to these two distinctive features.

Concepts for Primarily Vegetated Areas -1-When observing plant communities and considering their growth forms, two factors are fundamental:

• Physiognomy, the overall appearance of the vegetation; and

• Vegetation Structure, which is defined as “the spatial the spatial distribution pattern of growth forms in a plant community distribution pattern of growth forms in a plant community ”(Küchler and Zonneveld, 1988). The structure describes the individual layers, usually characterized by height and density of the respective growth forms.

Conceptual Basis

Tree layer

Tree layer

Shrubs heigh

t

Concepts for Primarily Vegetated Areas: -2-

Natural and Semi-Natural Vegetation (A12 and A24)

Conceptual Basis

The Life FormLife Form of a plant is defined by its physiognomic aspect (e.g., Trees, Shrubs, Herbaceous, etc.).

Two criteria need to be considered to determine DominanceDominance:

the primary criterion is (1) the uppermost canopy layer with the secondary criterion that (2) the dominant Life Form has a Cover either Closed or Open.The dominant Life Form in this example is Open Trees.

The dominant Life Form in this example is Closed Trees.

Concepts for Primarily Vegetated Areas: -3-

Natural and Semi-Natural Vegetation (A12 and A24)

Conceptual Basis

The dominant Life Form in this example is Closed Shrub because the cover of the trees is sparse.

The dominant Life Form in this example is Closed Herbaceousbecause the cover of the trees is sparse.

The dominant Life Form in this example is Open Shrubs.

The dominant Life Form in this example is Sparse Herbaceous.

Determine, for each of the four examples, the dominant Life Form. Select Closed, Open or Sparse in combination with either Trees, Shrubs or Herbaceous.

Concepts for Primarily Vegetated Areas: -4-Natural and Semi-Natural Vegetation (A12 and A24)Vegetation is grouped into so-called Structural DomainsStructural Domains, which are determined by the presence of characterizing key life forms and their respective cover:• Closed Trees (Forests): dominated by closed trees (shrubs or herbaceous may be present).• Open Trees (Woodlands): dominated by Open Trees (shrubs or herbaceous may be present).• Closed Shrubs: dominated by Closed Shrubs (trees can be present but only with sparse cover; herbaceous may be present).• Open Shrubs (Shrubland): dominated by Open Shrubs(trees can be present, but only with sparse cover; herbaceous may be present).• Grasslands: dominated by Closed or Open Herbaceous, Graminoids or Forbs (trees and/or shrubs may be present but only with sparse cover, e.g., Tree or Shrub Savanna).• Sparse Vegetation: dominated by Sparse life forms.• Lichens/Mosses: dominated by Closed or Open Lichens/Mosses (other life forms absent).

Conceptual Basis

Conceptual Basis

Concepts for Primarily Vegetated Areas: -4-(Semi)Natural Vegetation - Structural Domains overview

HER

BA

CEO

US

TREE

S

SHR

UB

S

X

OPEN(SHRUBLAND)

CLOSED (FOREST)

OPEN(WOODLAND)

CLOSED (THICKET)

CLOSED TO OPENCLOSED TO OPENGRASSLAND(SAVANNAS)

DEPENDING ON THEDOMINANT LIFE FORM

SHR

UB

STR

EES

Explanation of symbols :

SHRUBS

TREES

HERBACEOUS

SPARSE TO ABSENT

CLOSED

OPEN

CLOSED TO ABSENT

SPARSE TO ABSENT

CLOSED TO OPEN

CLOSED TO ABSENT

SPARSE TO ABSENT

CLOSED

OPEN

SPA

RSE

VEG

.H

ERB

AC

EOU

S

MAIN LAYER

Environmental and Specific Technical Attributes

Conceptual Basis

Environmental Attributes: these are attributes that are not inherent features of land cover but may influence land cover (e.g., landform, lithology, soils, climate, altitude, erosion, etc.).

They can be added to the land cover class as a further characterization of the land cover itself, rather than to add a new data layer.

Specific Technical Attributes: these attributes refer to the technical discipline of the major land cover type.

• Floristic AspectFloristic Aspect for (Semi)Natural Vegetation (A12 and A24)

• Crop TypeCrop Type for Cultivated Areas (A11 and A23)

• SalinitySalinity for Waterbodies (B27 and B28)

LCCS Software ApplicationLCCS Software Application

Classification ModuleClassification Module

Overview of the software application

Classification Module

build up legend

edit classes

create user-defined land cover classes

display legend

save and retrieve

print

export

FIELD DATA MODULEFIELD DATA MODULE

standardized general field data collection

specific field data collection

automatic extraction of land cover class from field

datasaving of field data in

synthetic formprint and export

TRANSLATOR MODULETRANSLATOR MODULEtranslation of external

classifications into LCCS

similarity of external single classes through

LCCS

comparison of twoexternal classifications

through LCCS

comparison of twoLCCS classes

all classifiers and attributesglossary

conditions to create land cover classes

database of all possible classes, including name, code

and descriptionimages and interpretation

database

CLASSIFICATION MODULE

LEGEND MODULELEGEND MODULE

PurposeThe Classification Module allows the user to define land cover classes according to two Phases:

• an initial Dichotomous Phase Dichotomous Phase where the user derives the main land cover type; followed by

• a subsequent ModularModular--Hierarchical PhaseHierarchical Phase where a land cover class is defined by determining one classifier at a time. Selection of classifiers at a high level may have consequences for optionsavailable at lower levels.

At any level within these Phases, a land cover class can be formed comprising its Boolean Formula, numerical code and class name.

Classification Module

The initial Dichotomous Phase Dichotomous Phase of LCCS

Classification Module

Click one option of each pair of buttons.

If the level of information needed or available to determine a land cover class is very limited, the user can select the appropriate choice(s) and a land cover class will be formed that can be stored by clicking the 2nd upper right button.

Or immediately identify to which major land cover type the class will belong by clicking directly on a button with the arrow.

The subsequent ModularModular--Hierarchical PhaseHierarchical Phase of LCCS

Classification ModuleThe so-called Environmental Attributes are presented in purple and are not hierarchically arranged; the Specific Technical Attribute is presented in green.

The sets of classifiers tailored to the major land cover and hierarchically arranged according tomapability (classifiers presented in dark blue).

ModularModular--Hierarchical PhaseHierarchical Phase: classifiers and attributes

• Land Cover Classifiers are hierarchically arranged according to mapability, i.e,. geographical accuracy, at the top levels.• Environmental Attributes are not hierarchically arranged and are shown at the intermediate levels.• Specific Technical Attribute is shown at the bottom.

Classification Module

The hierarchically arranged land cover classifiers over different levels at the top (in dark blue).

Followed by a set of Environmental Attributes (in purple).

The Specific Technical Attribute at the bottom (in green).

I

II

III

IV

I

II

ModularModular--Hierarchical PhaseHierarchical Phase: classifiers in detail

To proceed, click the upper left button (“Life Form and Cover ”in the example below). A new window will open, with a set of options.

Classification Module

The classifier Life Form is the first one to be determined.

I

II

III

IV

ModularModular--Hierarchical PhaseHierarchical Phase: classifiers in detail

Classification Module

Selection of an option of the classifier Life Form is made by clicking the appropriate button.

From the classifier Life Form, the option Trees has been selected.From the

classifier Coverthe option Closed has been selected.

From the classifier Height several options have become automatically disabled.

ModularModular--Hierarchical PhaseHierarchical Phase: attributes in detail -1-The user is free to add appropriate choices of Environmental Environmental AttributesAttributes in any order to the land cover class.

Use of attributes will result in:

• a separate string of codes separated from the classifier and optional modifiers by a hyphen;

• no alteration of the numerical code; and

• no change in the standard name, as these choices follow the standard name and each choice refers back to the attribute itself.

Use of the Specific Technical AttributeSpecific Technical Attribute will further define the land cover class using the related discipline. Use of the attribute has the same results as Environmental Attributes.

Classification Module

ModularModular--Hierarchical PhaseHierarchical Phase: attributes in detail -2-

Classification Module

The Environmental Attributes are listed below the standard Land Cover Class name.

The Environmental Attributes codes are listed separately.

Contact Address

If you have any questions concerning LCCS, please write to the following address:

Chief, Environment and Natural Resources Service (SDRN)Chief, Environment and Natural Resources Service (SDRN)

Sustainable Development DepartmentSustainable Development Department

FAO FAO -- Food and Agriculture Organization of the United NationsFood and Agriculture Organization of the United Nations

Viale delle Terme di CaracallaViale delle Terme di Caracalla

00100 Rome, ITALY00100 Rome, ITALY

THE END