Glacial and periglacial data integration in a GIs: methodology used in the Serra da Estrela, Portugal

Geological Quarterly, 2000,44 (1): 27-3 1

Glacial and periglaeial data integration in a

GIs:

methodology used

in the Serra da Estrcla, Portugal

Gonqalo Teles WEE4

Vieira 0 . T. (2000)

-

Crlaciaf and pcriglaciol data integration in a GIS: mcthodalogy used in the Serra da Estreta, Portugd. Geol. Quart., 44 (1): 27-3 1.

The methodology applied in the research in Serra da Estrela (Potttlgal} is to integrate glacial and pcriglacial gcomorphological data in a Geographical Information System and a Database Management System. The main objective of thc procedure is to make use of low cost software for geospatial data integration, statistical analysis and production of geomorphoEogicd mag. The digital storage format provides the means for fast access and easy tmnsportation of Ule data during field cnmpaigns. I t is also a very useful way to store the geomorphologicui data, so it can be used in the future by other researchers working in the area

GonpIa Teles Yreim, Centm de Estrrdas Geogr&cm, Unhvrsidade de Lisboa, Faculdade & L e m , CiAde Universitnriu, 160IF214

L~sboa, Por~ugol; e-maib [email protected] (received: August 12, 1999; accepted: September 27,1999). Key words: PortugaI, Serra dn Esttela, glacinl geomorpholagy, GIs, DBMS.

MTRODUCTION mapping, sedimenhlogical study ofthe d~posits and dating, led to a new lihe of research conducted by investigators from the Physical Geography and Environmental Research Group ofthe

The Serra da Estrela (1,993 m as.1.) is a granitic mountain Centro de Estudos Geogdficos (University of Lisbon), whicli

located in the Iberian Cordillera Central (Fig. I). It is a started in 1995.

significant ma

in

the framework of Quaternary science, as it It became clear very early that the data collection generated

presents the best preserved glacial and periglacial landscape of signscant amounts of information that would rapidly become Portugal.

ne

geographical position of the mountain at 40"20'N difficult to manage. It was decided to store the data in digital md

1 5 ,

and low altihlde make it an important format in order to promote an easy access to information,

site for palaeogeographical reconsmction in

the

western availability for statistical analysis, visualisation, printing, etc, European framework. Despite the absence of direct absolute Furthermore, the use o f CD-ROM for data storage should allow

datings, glacial deposits and landfms are attributed to the Last high mobility for the whole database (e,g, during fieldwork Glacial Maximum (Daveaq 1 97 1 ; Ferreira, I 998; Vieira and campaigns)-

Ferreira, 1998). 'I%e more significant periglacial evidences are Taking into account the financial limitations for the research

attributed to the same period, but mom recent periglacial events and the lack of personnel it was decided that the software should

seem to have occurred (Vieira, 1 998). Above ca. 1,750 m a.s.l., be affordable

and

relatively simple to use. Therefore, for the

marginal cryogenic processes are active today and play a role in construction and analysis of the cartographic database we use

the morphogenesis. the raster Geographical Information System

IL

WlS CJntegmted

General aspects ofthe glaciation of h e Serra da Estrcla were Land and Water Infomation System) and for the final outputs

fmt pointed out by Lautensach in 1932. In the late 60"s S . the design package Microstation 95 is employed. The alphanu- Daveau defined with a good accuracy the glaciation limits and meric data are stored in a relationaI data basr: management sys-

their chamcteristics (see Daveau, 1971). But until the mid-90's tern (cf. IAEA, 1993). The data transfer between the three pack- research on glacial and perigIacia1

problems

of the Serra da ages is relatively simple but not direct. In the future we intend to

Estrela had almost: stopped The need for better knowledge of compile the data in CD-ROM using a current Internet bmwser glaciation, especially rearding detailed geomorphological

as

a viewer (Fig. 2).

28 Gonqalo Teles Vieira

I

The examples presented in this paper relate to the geomorphoIogical research carried out in the ZGzere catchment (ca. 62 km2), chosen as the first area to be studied in the Serra da

'

Eslxela.

CARTOGRAPHIC DATABASE

The

cartographic database incorporates the spatiaI informa- tion and includes point, line and area (polygon and raster) data

and attribute tables (Fig. 33,

The

GI5

software that is used al- lows the djrect digitising (via digitising tablet or on-screen, us- ing a pointing device) of cartographic data (Budde e& al., 1997; Van Wesren and Parifteh, 1997; Van Westen et a/., 1997). The

data sources are published maps, aerial photographs, orthophotographic maps and field maps. Georeferenced points also can be entered into the database (e.g. txpostrres of deposits or

GPS

reference marks), Point, line and polygon data are linked to attribute tables. 11ese types of layers can only

be

used di- rectly for visualisation purposes; for analytical purposes a raster

transformation needs to be performed.

The geomorphoIogica1 data layers constructed in the GIs are to be exported to Microstation 95 and will be used For the

production of detaiIed geornorphological maps of the study

areas.

THE DlGFTAL ELEVATlON MODEL AND DERIVATIVE LAYERS I

The

Zkere

catchment Digital Elevation

Model

(DEM)

was

constructed from a 10 rn contour interval topographic map rasterized using 10 rn pixels. This size allows the detailed loca-

tion of the fentures in the field and a good spatial resolution for

the DEM. Fig. 1. Location of the Serrn da Estrcja in Pottug~l

D a t a b e M a n a g m t

Information System System

-

Ribliographical rcse=mh

-

Colle~tiog pre-cxisting m a p

-

Awinl photo inlerpmtion

-

Sedimentologicol analysis

I

Dnta a d y s i s

I I

S t m g d A r e h i ~ i y

I I

Compufer Aidcd Drawing

I

-

Reeonaissancc ofthe terrain

-

Dcbiled geommpholog~cal mopping -1dentificalion and sludy d t h e m&e s%psurcs -Photos ond obaemtions

-

Dmriptivc I Visualfsation based

-

Duailtd gmmorpholo~igicol

-

Quantilieatian I Morphamerrienl -Statistical

Glacial and perigIacial data integration in a GIs 29

Digital Elovation Modd

-

TopoPPfic

M P

-

_{D ~ n e ~ O T k} IL.LCssnd&+.

.m

Geologid map -w . . GeoIom-.r'-

--

b r n

Field survey _{. ~ i o l d k v s y path8}

,

photDgnphs

t + m

Pig. 3. CMogmphic datab1~3c of h e Zhere catEhmeot

I n gempatid analysis, theDEUis

we ofthemast

hpmt From the

DEM

it

is

pmsibIe h3genemte slope we

and

'

layers,

as

it

is

ibe ~ F W for the ~~n

of

ofher topographic q a c t maps

and

with

trigmmelrical

formulae applied

using

derivative Iayers (e.g

slope md wpe@ that

are important iterations, to calculate ashmiow map for a chosen d&

and

hour

w h b h h

a gemtatistical

approach

to geomorphologicaI (Vieira, 1999)

and

therefore potential radiation maps

mdysis (Fig. 4).

(Feficisimo, 1994;

Meijerhk et d ,1994; Vie& 1999)

pig.

4).

Slope

Angle Aspect

4

Digital Elevatiw

Modd

Potential Radiation (21 Dec)

Potential Insolation (21 Dec)

30 Goado Teles Vieha

Fig. 5. Display of the Dighi Elevation Model o f the Ztzcrc valley with shaded rcticf as draw file

Tfie Zeztre dcbrnent in markd in yellow, the main m i l = ridges in red and !he dnts reprepent h e exposum of Quaternary deposits

These

are especial& sigdlcant

in tbe

study of

@ial

and periglacial geommphoIogy.

The

DEM can also be used for generation of

cross-sections

and 3-D

vhaIisaeion

of

lhe landscape, ifnecessary, using also

raster drapes {e,g. geology or

location

ofthemoraines -Fig.

5).

Hydrography. Layers with the

hydrograpbicd

Wmx include the drainage network

and

the

Iakes

and dams.

They

were Wtised from the 1:25,000 topogmphc map. The lakes in

the Serra

da

W acorrespond to

old

glacier basins and are

relict glacial forms. A

unique

identEcation was given to

each

of

them, d they are linked to a table used

for

stmage of

refated

informdun.

The

&&age network layer sems for perfodng morphometrical analysis, and useful information can be retrieved from it enabling the

bc-

of

valley floors and

calcuIations derived h m k t parameter.

GeoIogy.

The

geology

layerrwas digitised h m the 1:50,000 g w l o g i ~ l map of the area

q d

represents the substratum.

Surface deposits were digitised in a s e p m t e hyer and were

mapped diredy

in

the

field.

The

geology

layer

is originaUy a

polygon layer connected to a

table

where the main

chwacteristics

of

the geological formations are incIuded. Whenever

an

analysis is to

be

done,

a raster layer with the

chosen

lifiological m u t e must

be

produced (e.g, texture,

lithologid

type).

Geomorphology.

The

constnrction

of

the

laye13

on

the

geomqhologicaI variables is one ofthe main objectives of the

study that is being carried

out

in the ZEzere valley. The data are

in

fact

a result of the

research

inthe area and therefore their inte- gration

proceeds

as new Eeld data become available.

The

~0morphoIogid layers include the swlicial deposits

and

the

landforms layer. They were constructed using field

obsmations

and

aerial

photo

hlqretation and their purpose

is

to serve

both

for visudisation

and geostatistical

analysis.

Exposures of deposits are represented in a point map with unique identifiers for

each

deposit and linked

to

a table that

allows

logging their geographical and

sedimentoIogica1

characteristics. The unique identifier allows fast access to

fhe

dphagumeric database

of

the deposits, which includes

photographs

and

sketches

of

the

exposum.

ALPIMNUMERIC

DATABASE

The

alphanumeric

database incIwles the gem-efmnced point data repmentiug the exposures

of

deposits and pictures taken during

field

wmk It

serves

both for archive

and

analysis purposes and can be exported to the GIS package.

The exposures database is an h u s t i v e

record

of

the

exposures

in

Quaternary deposits

and holds

photographs and

other significant sedimentological

and

interpretative

data

(Fig.

6).

The

datq can

be

used

for

statistical analysis and cattographic representation. It is a vrtluable

resource

for future research in the

area and aIso for landscape pImning issues

in the

h e w o k of the Sma

da

EstreIa MaturaI Park, as it allows for rapid W c a t i o n

of

the more

-

si

deposits

and

of

their &m&ristics.

Glacial and pcriglacial data integration in a GIS 31

Deposit exposures data Iayer

Deposit exposures data table

D.id Location TL FA MT Coord. x Coord. y Alt (...)

_--

USI-t US 1 -esp (,..)

. . . ... . . .

... C.S 3Ih3 ... . . . ... .,, . . .

...

Photo database

Ph.id D.id Datc Location Catchment Kcy-words Notcs (...I

. . .

... 5km

,

Fig. 6. Organisntion o f the dcposit exposum data in the GIS and DBMS (please note that the survey ofthe exposures in not yet cornplele)

The photographs database includes all the pictures (and observations on their characteristics) made during field work. The digital fonnat of the data makes ie especialIy easy for bansportatioi~ and therefore to be carried

in

field campaigns. In

this way, it is possible to visualise older photos and notes.

CONCLUSIONS

7l1e integration of the glacial and periglacial data of the Serra da Estrela in a GTS constitutes an excellent way for storage

of the data captured and produced during research projects in

the area. This data is easy to retrieve and use, both for visualisation and analytical procedures.

Expected uses for the database include the support for research conducted by investigators of the Centre de Estudos

Geogr3icos and by students ofthe Deparhncnt of Geography of tlie University oflisbon. A project with thc Natural Park of the

Serm da EstreIa is expected in order to promote the use of the database as a tool for planning purposes, especially in what

concerns to the conservation of the geomoiphological assets of

glacial and periglacial origin.

BUDDE P., BROEKEMA L., DOST R., VAN DUREN I. and EELDERIW

L. (1997)

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ILWIS 2.1 tor Windows, Reference Guide. ILWlS

Department, ITC. Enschedc.

DAVEAU S. (1971) -Laglaciation & l a Serrn daEstrela. Finistcrm Rev.

Partugucsa Geogr., 15 (1 1): 5 4 0 .

FELIC~SIMO A. M. (1 994)

-

mode lo^ Digitales det Terreno. Introduccibn y apl icaciones en la ciencias ambienlales. Penlalfa. Ovicdo. FERREIRA A. R. (1998)-Short note on the dating prohlcms of the glaciaI

and periglncinl events of lhe Serra da Eslrela. in: Glacial and Pcriglaciat Geomorpltology of t l ~ c Serradn Estrela. Guidebook for the field-tr~p (ed.

G. T. Vieira): 24-25. IGU Commission on Ciimate Change and Periglacinl Elmironments, 28-28 August 1998. CEG and Oepartmcntof Geography, University of Lisbon.

lAEA (1993)

-

Guidelines Tor the arganimtioi1 and management o f Earth sciences data on a personal computer, International Atomic E~iergy Agency, Vienna. unpublislied IAEA Tcchnical hcumcnt.

MEIJERTNK A. M. J.. DE BROUWER H. A. M., MANNAERTS C. M. altd

VALENZUELA C. R. (1994)- Introduction to the Use o f Geographic Infarmat~on Systems For Practical Hydrology. JTC Publ., no. 23. Enschede.

VAN WESTBW C. and FARTFTEH J. (1997)

-

ILWIS 2.1 for Windows, Users Guide. ILWIS Department, LTC. E~ischede.

VAN WESTEN C., SALDAYA LOPEZ A,, U R ! ~ CORNWO P. and

CHAVEI.

ARDANZA G. (1997)

-

ILWtS 2.1 for Windows, Applications Guide. I L W S Depnrtrnent, ITC. Eoschedc.

V I E I M G. T. (t998)

-

Periglacinl research in the Sern da Eslrela: an

overview. In: Glacial and PcriglaciaI Gcomorpliology o f the Serrn da Estrela. Guidebook for the iield-trip (ed, G. T. Vieirn): 4G-65. IGU Cornmissio~~ on Climate Change and Periglacial Environments. 26-28

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-

CAlculo do efeito de soinbra corn a Sistema de

lnforrna~Bn Geogrifico lLWIS 2.1. Docul~lentos de Trabalho, 3, CEG.

Lisboa.

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