Quality Control Data

Pedometric mapping

bridging the gaps between conventional

and pedometric approaches

SAMPLING - The chapter demonstrates how allocation of points in (b)

(a) N

the feature space influences the efficiency of prediction. It

suggests how to represent spatial multivariate soil forming

N

environment; how to optimise sampling design for environmental API

DEM

correlation and which sampling strategies should be used for a

SLOPE

general soil survey purposes.

EDOMETRIC PROFC

PLANC

PRE-PROCESSING - In this chapter, systematic methods for LAND USE

reduction of errors (artefacts and outliers) in digital terrain

MAPPING CTI

parameters are suggested. These methods ensure more natural (c)

SINS

and more complete representation of the terrain morphology, AP

which then also reflects on the success of spatial prediction.

bridging the gaps between conventional

bridging

AP_STD

and pedometric approaches

NDVI N

PHOTO-INTERPRETATION - This chapter suggests a semi-automated

method for extrapolating photo-interpretation from a limited number 2.5 km

0

of study sub-areas to the whole area. The intention was to enhance

Fig. 3. Multi-source predictors: (a) auxiliary predictors terrain

and not to replace the mapper s knowledge and expertise.

parameters and remote sensing data; (b) aerial photo-interpreta-

tion map (API) and land use map and (c) location of the 59 soil

INTERPOLATION - This chapter considers the development of a

profile observations. DEM elevation; SLOPE slope gradient in

flexible statistical framework for spatial prediction that should be

%; PROFC profile curvature; PLANC plan curvature; CTI

able to adopt both continuous and categorical soil variables. It

wetness index; SINS slope insolation; AP intensity of the

suggests methods for dealing with non-normality of input data

aerial photo; AP_STD standard deviation of the AP map and

and multicollinearity of predictors.

NDVI map derived from the Landsat 7 image.

VISUALISATION - In this chapter, an algorithm is suggested to

(a )

T. Hengl SMU1 - CM_ce (67%), RG_ce (33%)

visualize multiple memberships and to analyse geographical and SMU2 - CM_ce (50%), RG_ce (28%), CL_s (22%)

thematic confusion. Multiple memberships are visualized using the SMU3 - CM_gc (83%), GL_ce (17%)

Hue-Saturation-Intensity model and GIS calculations on colours. SMU4 - KS_cs (100%)

SMU5 - KS_cs (100%)

SMU6 - RG_ce (100%)

ORGANIZATION - This chapter collates methods from previous

The technological and theoretical advances in SMU7 - CM_ce (82%), GL_ce (9%), CL_s (9%)

chapters and describes organizational structure of a hybrid grid-

the last 20 years have lead to a number of new SMU8 - CM_ce (55%), KS_cs (27%), RG_ce (18%)

SMU9 - CM_gc (50%), GL_ce (50%)

based soil information system (SIS). It shows how to select a suitable

methodological improvements in the field of

grid size, how to aggregate and disaggregate soil information and

soil mapping. Most of these belong to the (b ) d)

what are the advantages and disadvantages of a grid-based SIS. The

domain of the new emerging discipline CL_s

prediction maps were produced using both photo-interpretation and

pedometrics. Pedometric mapping is generally CM_ce

auxiliary maps, which ensures both continuous and crisp transitions.

characterised as a quantitative, (geo)statistical CM_gc

production of soil geoinformation, also referred GL_ce

QUALITY CONTROL - In this chapter, systematic steps are KS_cs

to as the predictive or digital soil mapping.

RG_ce

suggested to assess the effective scale, accuracy of soil bound-

aries, accuracy of map legends, thematic purity of mapped

Many new pedometric techniques such as sampling optimisation N

( c)

entities and overlap among the adjacent entities. This assess-

algorithms, new interpolation techniques, fuzzy or continuous soil GL_ce

CM_gc

ment was based on a number of control surveys including control

maps are, however, still not fully applied in soil mapping at smaller,

profile observations and photo-interpretations.

i.e. regional scales. The polygon-based soil maps with crisp

definition of soil classes are still used as the state of the art KS_cs

KNOWLEDGE BANK

RG_ce

methodology. For a long time, the term pedometrics has been used DESCRIBED AND

(pedo-transfer functions,

CLASSIFICATION PARAMETERS

MEASURED SOIL

classification systems - CL_s

VARIABLES - class definitions (centers) soil types or suitability

as a challenge or contradiction of soil taxonomies, i.e. traditional (profile data) CM_ce

classes)

systems. This thesis is an attempt to bridge the gaps between the 0 2.5 km

INTERPOLATION PARAMETERS INTERPOLATE INTERPOLATED CLASSIFY USING

SOIL CATEGORIES

empirical and automated methods and improve the practice of soil SOIL VARIABLES SOIL VARIABLES CONTINUOUS

- regression coefficients (membership maps)

Fig. 4. Comparison of (a) the conventional soil map with

ON FINE GRID (raster maps) CLASSIFICATION

- semivariogram parameters

mapping by designing an integrative pedometric methodology. The compound composition of mapping units, (b) defuzzified (highest)

PREDICTORS:

thesis covers seven research papers/topics. API, ENVIRONMENTAL

membership map from the supervised fuzzy k-means classifica-

VARIABLES, REMOTE

SENSING IMAGES

(raster maps) INFERENCE PARAMETERS

tion with freely selected colours; (c) the continuous soil map with

RETRIEVE

- attribute tables

CLASIFFY

- parameters of the pedo-transfer

QUERY

a circular legend and (d) down-scaled map to 100 m grid. CL_s

functions

TRANSFORM

- suitability factor thresholds

PRE-PROCESSING

SAMPLING

Siltic, Calcisols; CM_ce Calcari-Eutric Cambisols; CM_gc

SOIL

Gleyi-Calcaric Cambisols; GL_ce Calcari-Eutric Gleysols; KS_cs

GEOINFORMATION

(soil types, land

qualities, spatial

Calci-Siltic Kastanozems and RG_ce Calcari-Eutric Regosols.

PHOTO- queries)

INTERPRETATION

?

QUALITY

ac

Fig. 2. S chematic flow of methodological steps used

CONTROL

"A richly illustrated enthusiastic exposition of digital

b

within the hybrid grid-based Soil Information System.

soil mapping... The author suffuses pedometrics in

every syllable... Some of the non-idiomatic uses of

The proposed pedometric mapping methodology can be used to

c

a

enhance the practice of soil mapping making the soil maps more English are very creative.

b

1.00

INTERPOLATION

ORGANIZATION

objective, detailed and more compatible for integration with other The particular strength of this thesis is that it defines

0.00

environmental geo-data. There is no need to use the concept of soil

most or all of the aspects of pedometric mapping

mapping units or use double-crisp soil maps anymore. On the other

VISUALISATION

that require attention... and tackles them!"

hand, instead of abandoning photo-interpretation, soil classification

Fig. 1. S chematic outline of the topics discussed in the

or empirical knowledge on soils, these methods can be successfully

thesis. Note the circular structure, which symbolizes that Alex B. McBratney, University of Sydney

integrated with pedometric techniques.

the soil maps need to be periodically updated.

Hengl, T. 2003. Pedometric mapping: bridging the gaps between

For more information: the conventional and pedometric approaches. PhD thesis,

Wageningen University.

Tomislav Hengl

ITC Dissertation number 101, ITC, P.O. Box 6, 7500 AA Enschede,

AGIS centre

The Netherlands. Parts of the thesis are available on-line via the

Faculty of Agriculture

ITC s library website www.itc.nl/library/

Trg Sv. Trojstva 3,

31000 Osijek, Croatia

E-mail: *****@***.**

Home Page: http://www.pfos.hr/~hengl/

INTERNATIONAL INSTITUTE FOR GEO-INFORMATION SCIENCE AND EARTH OBSERVATION

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