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Geomorphological mappingGeomorphological mapping
CaseCase studiesstudies inin coastal environmentcoastal environment
(beaches(beaches/rock/rock cliffscliffs))
1)1)^ Main objectives ofMain objectives of geomorphological mapsgeomorphological maps
2)2)^ Data toData to mapmap
3)3) RulesRules ofof mappingmapping
4)4) General methodologyGeneral methodology
5)5) PracticalPractical exercice ofexercice of geomorphological mappinggeomorphological mapping
Contents ofContents of the presentation Contents of the presentationthe presentation
Contents ofContents of thethe presentationpresentation
Geomorphological maps
= the most appropriate and synthetic ways of showing the spatial distribution of :
-landforms,
-surface and near-surface deposits
-processes that act on landforms
-the time of the action of these processes
- Main objectives of1) Main objectives of geomorphological maps 1) Main objectives of geomorphological mapsgeomorphological maps
= Important products of investigations made by geomorphologists on the territories
= Usefullness to (Ahnert, 1998, Gustavsson et al., 2006 , Griffiths & Abraham, 2008) :
-professionnals dealing with the landscape and landforms
-engineers
-urban planners
-soils, forests scientists
-land conservationnists
-risks managers
-etc.
Î better analysis and understanding of landscape development
contain information on the morphology, genesis and age of landforms.
take into account the topography and the geological structure
can be enriched in attributes including slope, aspect, soils, climate and
vegetation
try to explain the landforms genesis
Geomorphological maps (^) = Geological maps
ButBut detailled geomorphological mapsdetailled geomorphological maps areare frequently consideredfrequently considered as a timeas a time--
consuming and costly activityconsuming and costly activity ……
Geomorphological maps
……EvenEven ifif the accuracy and speed of mapping is continuously beingthe accuracy and speed of mapping is continuously being
improved by the availability of more sophisticated equipment, inimproved by the availability of more sophisticated equipment, in
particular, GPSparticular, GPS
- Main objectives of1) Main objectives of geomorphological maps 1) Main objectives of geomorphological mapsgeomorphological maps
The quality that any map shouldThe quality that any map should havehave is the easy readabilityis the easy readability ofof
relevant informationrelevant information
3)3) Rules 3) Rules of mappingRules ofof mappingmapping
All the rules of mapping must, of course, be respected
A precise title (where, when, what ?)
For easy orientation in the field, it is advantageous if the geomorphological map is
based upon a geo-referenced topographic map or orthophotograph that shows
selected infrastructure and also gives contour lines.
The legend must be clearly structured and logical to facilitate the overview
(there is a need of classification of each data before drawing the map)
The number of symbols must be kept low for easy use
One geomorphological fact to map = one symbol
A structured legend (themes, sub-themes, etc.)
A graphic scale (rather than numerical)
The orientation (the North and/or geographical coordinates)
The references of data
The author of the map as well as the date of realisation
Geomorphological
map of France
Brest
3)3) Rules 3) Rules of mappingRules ofof mappingmapping Brest
Geomorphological
map of France
Brest
3)3) Rules 3) Rules of mappingRules ofof mappingmapping
A detailled and precise map… but also a work of art
3)3) Rules 3) Rules of mappingRules ofof mappingmapping
A structurated legend…
3)3) Rules3) Rules of mappingRules ofof mappingmapping
Adaptation of the legend when chronology is the most important fact to better
understand the morphology… (river terraces)
3)3) Rules 3) Rules of mappingRules ofof mappingmapping
Chronology of the landforms
Landforms related to river
terraces
Change of the colours to
indicate the period
Other main information:
granulometry and composition
of the terrace deposits
Adaptation of the legend when chronology is the most important fact to better
understand the morphology… (river terraces)
3)3) Rules3) Rules of mappingRules ofof mappingmapping
Other example : Ouessant island (western Brittany) Î lithology and tectonic
Ouessant
3)3) Rules 3) Rules of mappingRules ofof mappingmapping
Other example : Ouessant island (western Brittany) 1/25 000
4)4) Methodology4) MethodologyMethodology
1 st^ step = Conception of the legend of the map based on field observations and remote sensing of aerial photos
-Classification of morphological features into
themes, sub-themes, etc.
-Present-day geomorphological processes
-Lithology
-Topographical data to map
-etc.
-Choice of the symbols and colors or black and
white to apply
For example, refer to:
4)4) Methodology 4) MethodologyMethodology
L’Île-Tudy Combrit
A « simplified» way to build the legend of a geomorphological map…
4)4) Methodology 4) MethodologyMethodology
Black and white example
Erosional Erosional
landformslandforms
LandformsLandforms duedue
toto
accumulationaccumulation
ContinentalContinental CoastalCoastal SubSub--marinemarine AnthropogeneticAnthropogenetic
ProcessesProcesses
TopometricTopometric datadata
A « simplified » way to build the legend of a geomorphological map…
4)4) Methodology 4) MethodologyMethodology
4)4) Methodology4) MethodologyMethodology
2d step = Conception of the map based on georefenced topographical and geological maps, DTM (if existing) and aerial photos.
3 rd^ step =The base map is then 'ground truthed' in the field. Ground truthing is an important part of the process to validate the map (small scale features can often be missed, and larger scale features can be misinterpreted).
5)5) Practical 5) Practical exercice of geomorphological mappingPractical exercice ofexercice of geomorphological mappinggeomorphological mapping
5)5) Practical5) Practical exercice of geomorphological mappingPractical exercice ofexercice of geomorphological mappinggeomorphological mapping
5)5) Practical5) Practical exercice of geomorphological mappingPractical exercice ofexercice of geomorphological mappinggeomorphological mapping
5)5) Practical 5) Practical exercice of geomorphological mappingPractical exercice ofexercice of geomorphological mappinggeomorphological mapping
5)5) Practical5) Practical exercice of geomorphological mappingPractical exercice ofexercice of geomorphological mappinggeomorphological mapping
1) Identify and list all the facts to map, especially the geomorphological features
2) List the main topics
Etc.
5)5) Practical 5) Practical exercice of geomorphological mappingPractical exercice ofexercice of geomorphological mappinggeomorphological mapping
1) Identify and list all the facts to map, especially the geomorphological features
2) List the main topics
Etc.
3) Choose
the colour
5)5) Practical5) Practical exercice of geomorphological mappingPractical exercice ofexercice of geomorphological mappinggeomorphological mapping
1) Identify and list all the facts to map, especially the geomorphological features
2) List the main topics
Etc.
3) Choose
the colour
4) Separate erosional features from
accumulations
5)5) Practical 5) Practical exercice of geomorphological mappingPractical exercice ofexercice of geomorphological mappinggeomorphological mapping
5)5) Practical5) Practical exercice of geomorphological mappingPractical exercice ofexercice of geomorphological mappinggeomorphological mapping
5)5) Practical 5) Practical exercice of geomorphological mappingPractical exercice ofexercice of geomorphological mappinggeomorphological mapping
Some references :
-Carton, Coratza, Marchetti, 2005, Guidelines for geomorphological sites mapping: examples from Italy. Gémorphologie : relief, processus, environnement , 3, 209-218.
-Demek, J. and C. Embleton (eds) 1978, Guide to Medium-Scale Geomorphological Mapping. Zeitschrift für Geomorphologie Supplement band 68.
-Gustavsson, Kolstrup, Seijmonsbergen, 2006, A new symbol-and-GIS based detailed geomorphological mapping system: Renewal of a scientific discipline for understanding landscape development. Geomorphology , 77, 90–
-Gustavsson, Seijmonsbergen, Kolstrup, 2008, Structure and contents of a new geomorphological GIS database linked to a geomorphological map, with an example from Liden, central Sweden. Geomorphology 95, 335–349.
-Guthrie R.H., 2005, Geomorphology of Vancouver Island: Extended legends to nine thematic maps. Research Report n° RR 02, Ministry of Environment, British Colombia, 27 p.
-Hénaff A., Lageat Y., Costa S.,2006, Geomorphology and shaping processes of chalk shore platforms of the English Channel coasts. Zeitschrift für Geomorphologie , supplement volume 144, p. 61-91.
-Joly F., Glossaire de géomorphologie, base de données sémiologiques pour la cartographie. Collection U, A. Colin, ppp
-King, R.B. 1986, Review of geomorphic description and classification in land resource surveys’ in V. Gardiner (ed.) International Geomorphology Vol. II. (Chichester: John Wiley and Sons,), pp.384–403.
http://geographie2001.free.fr/TDgeo.html#g%C3%A9omorphologie
