Jun Chen1,2

1Chief Scientist, National Geomatics Center

2President, ISPRS 25 May, 2016 , Rotterdam, The Netherlands

“Sensors”, GSW 2016

Contents

Methodology

Outlook

Background

Organization

Validation of Land Cover Maps

Documentation of the accuracy of land cover maps allows users to evaluate the utility of these maps for their particular applications

Image pre-processing

classification Verification

LC product Validation

1 2 3

GlobeLand30 - the World’s first 30m Earth Land Cover Map

Chen , et.al., 2014, China: Open access to Earth land-cover map, Nature, 514:434, 23

Oct. 2014

www.globeland30.org

POK based Operational Mapping

5

Chen et.al., 2015. Global Land Cover Mapping at 30m Resolution: a POK-based Operational Approach，

ISPRS Journal of Photogramme try and Remote Sensing , 103 (2015): 7-27

Per-class

extraction

Water

Wetland

Snow & Ice

Artificial cover

Cropland

Forest

Shrubland

Grassland

Barren land

Tundra

Pixel-based classification

Spectral

features

30m imagery NDVI time-series Reference data

Textural

features

Multi-temporal

information

Object-based identification

Multi-scale

segmentation

Automatic

labeling

Object-based

result

Supervised classifiers/Decision trees

Knowledge-based verification

Knowledge

integration

platform

Manual

interaction &

verification

Quality control

and product

integration

Global land cover mapping at 30m resolution

Pixel-based classification

Object-based Identification

Knowledge-based verification

Per-class extraction

Geographical Distribution of Users

111 countries and 6000 users

Geographical Distribution of Users

Download Frequency

90

88

87

85

82 84 86 88 90 92

Hybrid map

GlobeLand30

Hansen's TC

JAXA forest map

Overall accuracy,%

Preliminary Validation of GlobeLand30

Sample points

accuracy

Investigators and

sources

Full class 154,070 83% 5 Chinese institutions

Water ,N. Europe

91% (Prof. Y-F Ban)

GIM, Dec.,

2014

Forest IIASA

Report

Validation at individual countries

Country (Investigator)

Areas Accur. Sources

Germany (Dr. J. J. Arsanjan)

Whole Germeny (CORINE, UA, OSM, and ATKIS)

92% Int. J Digital Earth, 2016(on line)

Greece (Dr. Ioannis Manakos)

Thessaly Region

91% Land, 2015, 4,1-18

Iran (Dr. J. J. Arsanjan)

6 study sites

77.9% Habitat International ,2016,1-7

Italy (Prof Maria Broveli)

8 areas >80% Remote Sensing, 2015(7), 2107-2122

Towards a Comprehensive Validation

Separate and independent accuracy assessments of some 30-m products being made

A comprehensive validation of multiple 30-m GLC maps would allow comparative assessments of uncertainty among different maps

Output from an GEO/ISPRS Workshop (6-7 June 2015, Shanghai)

The workshop "Trust in Spatial Data and Validation of GLC

Products" discussed the issues related to the validation of

30m GLC products with suggestions:

this international validation activity be led by GEO and

ISPRS, co-organized by some other organs (i.e., UN-

GGIM,…).

all the existing 30m GLC products (including GlobeLand30)

be validated with the same approach.

be conducted from Aug. 2015 to the end of 2016.

Contents

Methodology

Outlook

Background

Organization

Major tasks

• Develop advanced tools for facilitating

the validation processes

• Formulate a technical specification suitable for the validation of

30-m GLC data , including the sampling design, response design and analysis protocols

• Organize collaborative validation and report to

GEO plenary

• Mobilize GEO members and participating organizations,

including Integrating all available validation resources and expertise

The Existing Verification Technology

The Top-level Designing of Global Land Cover products

in 30 m Verification

Estimation of Sample Size· Two-ranking sampling· Multiple stratified

sampling

Layout of Sample· Regular grid· Landscape index

· Spatial correlation

Integration of Resources· Semantic mapping· Scale conversion

· Phase integration

Online Check· Interactive

interpretation

· Credibility

Accuracy Assessment· Confusion matrix· Area-weighted overall

accuracy

· Kappa

Technical Specification· Sampling scheme· Sample check· Accuracy assessment

· Online geo-tagging

Global Overall Accuracy

Assessment

Regional Verification

R&D and Testing Online Verification System

Major Methodology

Identify or develop suitable methods for 5 key items

Conceptual design

Develop online tools

Formulate a technical specification (guidelines）

A Landscape-Index Based sampling approach

More reasonable sample densities and sample sizes derived using the LSI approach

Country rLSI Sample size Sample density

SRS

Mauritania 2978 29 Spain 1461 29

Bangladesh 426 29

SWS Mauritania 1910 19

Spain 2115 42 Bangladesh 460 31

LSI Mauritania 1.29 1579 15

Spain 2.68 1627 32 Bangladesh 3.46 617 42

Countries with different spatial heterogeneities

SWS-Shannon index-based cluster sampling

SRS-stratified random sampling

On line Validation System

Collaborative Validation

Region based validation

Global Validation

Continent Based validation

Feature based validation

Country based validation

Coordination

Technical Specification Validation support tools

Sample plan

· Sample plan for region

· Sample plan for country

· Sample plan for continent

· Sample plan for feature

Validation Resources

· GLC products· HR images· Aerial photographs· Geo-tagged pictures· Geo-wiki/DCP· In-situ measures

Assessment

· Assessment report for region

· Assessment report for country

· Assessment report for continent

· Assessment report for feature

· Global assessment report

Sampling

· Collaborative collection of samples from world

· Distribution of samples to world

Contents

Methodology

Outlook

Background

Organization

Key Players

NGCC

GOFC/GOLD

IIASA

Tongji Uni.

KTH

CO-DATA

ISPRS

…

Collaborative Validation

Initiativing Validation

A GEO-led Validation

Establish a GEO-led collaborative framework for the validation of GLC data products

Complete the validation (assessment) of all available multiple 30-m GLC maps

40 countries and PO joined

25个GEO members and 15个others（UN-GGIM、CO-DATA）

序号 国家/组织 序号 国家/组织 序号 国家/组织

1 Bulgaria 14 UAE 27 Mongolia

2 Canada 15 Zimbabwe 28 Thailand

3 China 16 Sweden 29 EU- JRC

4 Czech Republic 17 Rwanda 30 FAO

5 Ecuador 18 Uganda 31 ISPRS

6 Laos 19 Indonesia 32 IIASA

7 Greece 20 Brazil 33 CODATA

8 Italy 21 Mexico 34 GOFC-GOLD

9 Japan 22 Argentina 35 PAIGH

10 Portugal 23 Shirilanka 36 RCMRD

11 Romania 24 Tanzania 37 UNGGIM

12 South Africa 25 Columbia 38 UNESCAP

13 Ukraine 26 Jordan 39 ECA

Countries Participated

Workshop on Validation of GLC Datasets June 28 – 30, Tongji University, Shanghai

http://celiang.tongji.edu.cn/GLCVal2016/Home.html

, Generic approaches for validation of land cover datasets Validation schemes for GLC datasets at various spatial resolutions Allocation of global samples in the case of heterogeneity and

correlation Accuracy assessment in remote sensing-derived GLC datasets Development of online tools for validation of GLC datasets Identification of scientific/technological/application challenges related

to GLC validation Trust and degree of trust in validation of global land cover datasets Others

A Special Issue on ISPRS J Geoinformation

http://celiang.tongji.edu.cn/GLCVal2016/Home.html

present the new concepts and outputs of GLC datasets

validation, including algorithms and models of validation

schemes, sample collection and accuracy assessment, as well as

on-line validation and tagging tools.

not limited to the GEO led international validation campaign..

Validation on Global Land Cover Datasets

Contents

Methodology

Outlook

Background

Organization

Outlook

Establish a GEO-led collaborative framework for the validation of GLC data products

Report both the validation results and the collaborative validation framework to GEO community

Lead to a coordinated regular validation practices

Thanks

Thank your attention！

www.globeLand30.org

chenjun@nsdi.gov.cn