Geoscience Reference
In-Depth Information
Best Pratices for Polygon Generalisation from
medium to small Scale in a GIS Framework
Andriani Skopeliti
Cartography Laboratory, National Technical University of Athens
9 Heroon Polytechniou, Zographos 15780, Athens, Greece
askop@survey.ntua.gr
Abstract
The paper preseQts a best practice apprRach fRr the geQeraOisatiRQ Rf
pROygRQ data iQ a GIS eQvirRQPeQt TwR PaiQ issues are addressed the
tRpRORgicaO iQtegrity betweeQ differeQt thePes with iQterthePe cRQstraiQts
aQd the PaQagePeQt Rf thePes that are stRred iQ the database with duaO
geRPetries such as pROygRQaO uQits aQd their OiQear bRrders The use Rf aQ
auxiOiary dataset that resuOts frRP the appOicatiRQ Rf the Pap RverOay
PethRd vuQiRQw tR a QuPber Rf pROygRQ thePes is iQtrRduced It caQ be
used tR sROve iQcRQsisteQcy prRbOePs Rf the RrigiQaO datasets aQd tR suc
cessfuOOy haQdOe geQeraOisatiRQ by suppOyiQg structuraO NQRwOedge The
PRdeOOiQg Rf pROygRQaO uQits aQd their OiQear bRrders iQ a spatiaO database
is discussed aQd the use Rf tRpRORgicaO reOatiRQships fRr geQeraOisatiRQ is
prRpRsed These best practices have beeQ successfuOOy tested iQ the ruOe
based geQeraOisatiRQ perfRrPed iQ the fraPewRrN Rf the ESDI1 prRgraP iQ
Rrder tR prRduce a paQ - EurRpeaQ sPaOO scaOe dataset frRP PediuP scaOe
RQe
.
1- Introduction
National Mapping and Cartographic Agencies (NMCAs) invest on an
annual basis considerable time and effort to provide updated data at medium
(1:250 000) and small scale (1:1000 000) in order to contribute to a pan-
European dataset handled by Eurogeographics. Since the majority of the
themes such as Administrative Units, Populated Areas etc. are common to
the two spatial datasets, the updating process is repeated. The automatic
derivation of small scale data from medium scale data through generalisa-
tion is a strategic goal for NMCAs. In this way the update activity will be
