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Cadastral Mapping of Forestlands in Greece:
Current and Future Challenges
Moschos Vogiatzis
Abstract
The Hellenic Cadastre Program (HCP) of Greece aims at
developing a modern cadastral system for the first time in
the Hellenic history. This paper is focused on the issues
related to cadastral forestlands digital mapping, an indispensable part of HCP. Mapping the forestlands is a challenge
of multiple disciplines. It includes photogrammetry, photointerpretation, Geographic Information Systems (GIS), and a
clear understanding of the current institutional and legislative setting. The process requires both historical and current
information pertaining to land-cover in order to identify
forestland changes over time. Historical and current digital
orthoimagery is generated through photogrammetric operations. Forestlands are delineated in a spatiotemporal environment; state property rights in forestlands are allocated
and land ownership is established within the framework of
HCP. This paper demonstrates that the integration of airborne
remote sensing and collateral data with a GIS is an effective
approach for cadastral forest mapping. The produced GIS
databases and large-scale Forest Maps may serve as a data
foundation towards a land register of forests.
Introduction
Forestland mapping, along with ownership, is an unaccomplished task for forestry in Greece. This affects land administration, sustainable resource management, and adequate
planning for a wide range of activities. The catastrophic
wild fires of the last decades, the illegal encroachment on
forestlands, and the degradation of natural resources over
time have made this task extremely difficult.
The need for natural resource conservation along with
urban and environmental planning, requires reliable data.
The HCP provides an opportunity to achieve the above needs
by integrating multiple types of information. Within the HCP,
cadastral forest mapping deals with forestlands boundary
delineation and their associated characterization (forest/nonforest) based on the land-cover characteristics from multitemporal remotely sensed data (Green et al., 1993a). In
addition, it takes in account a plethora of existing data, such
as administrative deeds issued by local Forest Services and
historical cadastral or land distribution diagrams, to document property rights in forest lands.
The project aims at developing multi-date digital forest
maps, at a scale of 1:5 000 depicting forest/non-forestland
status and extent over time to attain the following tasks:
(a) protect forests and forestlands effectively, (b) acquire
precise information on the boundary and geographic extent
of forestlands and ensure state ownership through cadastral
process, and (c) provide digital data sets to the Hellenic
Forest Service for land management and planning.
The project relies on the integration of airborne data
and existing data within a GIS. Conventional aerial photography has long been used in natural resources as a valuable
source of information on land-cover and vegetation mapping
(Welch et al., 2002; Congalton et al., 2002). In this project,
it is used for reasons of spatial resolution and historical
information enforced by law (Green and Hartley, 2000).
Multi-date digital orthophotomaps have been generated at a
fine-grained resolution to serve as a planimetric base for
forest/non-forest land boundary mapping (Duhaime et al.,
1997). Handling and maintenance of large spatial as well as
non-spatial data were used or derived by such large scale
mapping projects has been enabled in a geospatial environment provided by GIS. The major issues of the project are:
(a) the use of historical photography and respective digital
orthoimagery generation, ( b) forestland classification system
suitable for use with aerial photography and sufficient to
meet the project requirements, and (c) implementation of
cadastral forest mapping in relation to Hellenic Cadastre.
In this paper, methods based on analogue photointerpetation, photogrammetry, and GIS will be applied to address
the above issues, and assist in the implementation of this
innovative initiative for cadastral forest mapping.
Institutional Framework
Over time, there have been various definitions of forests in
Greece. The current legal definition of forest and forestland (expanse) is contained in Article 24 of the Constitution, as amended in 2001: “Forest or forest ecosystem
means the organic whole of wild plants with woody trunk,
on the necessary area of soil which, together with the flora
and fauna co-existing there, constitute via their mutual
interdependence and interaction, a particular biocoenose
(forest biocoenose) and a particular natural environment
(forest-derived). A forest expanse exists when the wild
woody vegetation, either high or shrubbery, is sparse.”
Moreover, the Constitution makes special provisions for
the protection of forests and forestlands. Article 24 of the
Constitution prohibits alteration of forests and forest landuse, unless it is enforced by public interest. Public and
private forests and forestlands destroyed by fire or other
causes are obligatorily under reforestation regime, and their
Photogrammetric Engineering & Remote Sensing
Vol. 74, No. 1, January 2008, pp. 39–46.
KTIMATOLOGIO S.A. (Hellenic Cadastre), Regional Center
of Thessaloniki, 4 Aggelaki, 54621 Thessaloniki, Greece
([email protected]).
PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING
0099-1112/08/7401–0039/$3.00/0
© 2008 American Society for Photogrammetry
and Remote Sensing
January 2008
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disposal for other purposes is prohibited (paragraph 3,
article 117). Expropriation of forests and forestlands owned
by private or public bodies is permitted only in cases
benefiting the State, but their designation as forests shall be
retained unaltered (paragraph 4, article 117).
These constitutional provisions and related forest law
regulations at least theoretically secure forest protection
from excessive interventions of owners and third persons as
well as from natural factors. However, human interventions
are still allowed in forests and forestlands under certain
legislative terms.
Forests and forestlands have not yet been mapped in a
systematic and scientific way. They cover about 6,505,499 ha,
that is, 49.3 percent of the total country area (National
Inventory of Forests, 1992). According to the Greek Ministry
of Rural Development and Food (2005), privately owned
forests cover about an area of 199,870 ha. Municipalities,
charitable foundations and monasteries own forest areas of
422,698 ha. The Hellenic Forest Service administers the rest
of lands as public lands including grasslands. Grasslands
are dominated by specific non-woody vegetation (low
formations of shrubs, phryganas) with canopy cover less
than 15 percent, located in lowlands or hills with elevation
up to 200 m (Ministerial Circular No. 159140/1077, 1980),
and they are mainly spread over Greek islands and the
coastal zone. On the mainland, they may be found in
transition zones between forestland and rural areas. It is
estimated that these lands cover approximately 1,600,000 ha
(WWF Hellas, 1999).
State ownership of forestlands and grasslands has been
legally recognized by a series of Royal Decrees since 1833.
The State retains its property rights in these lands ever
since, unless private use of these lands can be documented
for 30 consecutively years until 1915 or during the Ottoman
occupation of Greece, however, it has never been able to
develop a land register of forests and secure its property
rights. Instead, the administration in Greece favors the
practice of the circumstantial confirmation of whether
certain disputed areas are forests or non-forests, a process,
which deprived forests of protection (Decleris, 2000).
The efforts for cadastral mapping of forests and forestlands in Greece started in 1976 (Government Gazette No. A-6,
1976). That ambitious project, known as “Forest Cadastre”
resulted in the production of forest cadastral maps but
covered only an area of 320,212 ha across Greece. It was
initiated by the Hellenic Forest Service and has been long
used for land administration.
In 1996, KTIMATOLOGIO SA (KT) and Hellenic Mapping
and Cadastre Organization (HEMCO), the leading state agencies
responsible for the development of national cadastre in
Greece, contracted with private companies or joint corporations to implement cadastral mapping in 341 municipalities
across Greece (Potsiou et al., 2001). Contract areas range from
672 to 39,000 ha (Figure 1). Cadastre development comprises
of all the land properties, and therefore forestland cadastral
mapping is necessary for a successful cadastre establishment
(Zentelis and Dimopoulou, 2001).
The success of the cadastral forest mapping depends on
the close cooperation between KT and the Hellenic Forest
Service, which is responsible for the review of forest maps
in terms of boundary position and land characterization
(forest/non-forest) accuracy. Final forestland boundaries and
land status are determined through special procedures of
Law No. 2664/1998, which include wide public notification
for forest map content, appeal collection, and processing
(Government Gazette No. A-275, 1998). The final Forest
Map includes all forestlands to which provisions of the
forest legislation are applied and are valid. It is officially
authorized and declared to be final by the Regional General
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January 2008
Figure 1. The current Hellenic Cadastre Program.
A color version of this figure is available at the ASPRs
website: www.asprs.org.
Secretary. Therefore, it has full probative validity to every
administrative or judicial authority.
Property rights in forestlands are determined through the
institutional procedures of the HCP, where state and third
party property rights declarations are collected and processed
resulting in cadastral diagram development and registration
of property rights. The program is based on the principle of
publicity to ensure transparency and public faith.
The issues related to forestland ownership have not
been resolved for years, due to administration weakness to
delineate and protect state property, and thus resulting in
a complicated legal framework. Still the legal framework
regarding forestland ownership is confused in areas unique
worldwide, such as, Ionian Islands, Cyclades, and Crete, and
should be clarified.
Forest boundaries and land status have not been institutionally authorized through final Forest Map development,
which resulted in numerous problems, such as state versus
private disputes over forestland and property rights registration; proper cadastre development prerequisites the final
Forest Map. Thus, state property rights in forestlands and
grasslands will be provided early enough, and control of
property rights legitimacy will be facilitated. In this way, the
respective disputes on all forestlands and grasslands will be
minimized and cadastre implementation will be accelerated.
Materials and Methods
Digital Orthoimagery
The use of digital orthophotography has been used as basic
source of information. National programs (Teselle et al.,
1994 and 2001; Winkler, 2001; Mas et al., 2002) have been
applied worldwide to obtain country coverage for multiple
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reasons, e.g., environmental monitoring, mapping, and
update of existing maps. In HCP, digital orthophotos are used
as the standard planimetric base for cadastral data survey
and forestland mapping. The instrumentation, hardware,
and software used in either recent or historical orthophoto
generation vary depending on systems used by contractors.
Current black and white aerial photography (1:15 000
scale) in 23 cm 23 cm format acquired by HEMCO across
each contract area was used as the primary data source for
cadastral mapping. The respective film diapositives were
scanned using high quality scanners (e.g., Z/I Imaging
PhotoScan® and Leica DSW) to produce digital photos of
less than 21.2 m pixel size (1,200 dpi resolution). All
necessary measurements for interior and exterior orientation
were carried out in photogrammetric stations (analytical
or digital) using traditional photogrammetric techniques.
Bundle block adjustments were employed to control blocks
of variable number of scanned photos in each contract area.
A geodetic network was established in each contract area
based on the State trigonometric network. Ground control
points (GCPs) were collected uniformly across each contract
area utilizing Global Positioning Systems (GPS) techniques.
Digital terrain models (DTMs) were generated by collecting
points (manually or automatically) in a regular grid arrangement with a grid distance equal to 40 m. Additionally, these
DTMs were reinforced by other morphological data, such as
breaklines and spot elevations. The DTMs in conjunction
with the scanned images and orientation parameters were
then used to generate orthophotos with a ground (pixel)
sample distance (GSD) of 0.5 m. Orthophoto image accuracy
is reported in ground distance and is less than 2 m, which
meets the final map scale accuracy standards (HEMCO, 1997).
A current orthoimage tile has a file size of 50 megabytes.
Historical aerial photography is a unique record of
historical information used for diverse purposes worldwide
(Luman et al., 1997, Raumann et al., 2004). The first aerial
photography coverage of Greece was acquired by the U.S. Air
Force in 1945. It was taken by reconnaissance cameras and
consequently lacks fiducial marks and camera calibration data.
Historical aerial photographs of 1945, and diapositive transparency reproductions were obtained from HEMCO through
license of the Hellenic Military Geographical Service, which
maintains a repository of 13,200 negatives, in the form of
individual frames.
Diapositives were scanned at 1,700 dpi at 8-bit grayscale
using high quality photogrammetric scanners at the contractors’ sites. These scanning rates were determined, through
experimentation, as optimum to reveal high feature detail on
historical imagery. In areas where 1945 aerial photography
does not exist, we used aerial photography from 1960.
Photogrammetric techniques for processing historical photography taken by non-metric cameras have been already
developed (Walstra et al., 2004). To obtain interior orientation parameters, the staff of Directorate of Forest Mapping,
Ministry of Agriculture used laboratory methods for camera
calibration (Wolf and Dewitt, 2000). They establish virtual
fiducial marks on specific points along the edges of each
diapositive using a point transfer device. Image coordinates
of fiducial marks are measured using a monocomparator and
transformed to photo coordinates. The interior orientation
accuracy ranges from 4 m to 30 m.
Historical orthophoto generation employs the recent DTM
that is edited where significant changes have been occurred
on the Earth’s surface, such as mines or construction sites.
At least ten tie points were selected in each stereomodel.
In most contracts, a block bundle adjustment was applied
for the spatial orientation of historical scanned aerial photographs. Sources of photo control points were common points,
such as rocks, churches and road intersections, to both
PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING
historical and recent stereo photo pairs. These points were
identified in recent orthophotos and their coordinates were
measured.
Historical orthophoto accuracy depends mostly on the
accuracy of recent orthorectified imagery (Wang and Ellis,
2005). In all contract areas, historical orthophoto accuracy met
the standard accuracy (10 m positional error at 90 percent
confidence) in image co-registration with recent orthoimagery.
Historical orthophoto image GSD is 1.0 m.
The produced digital orthoimages are referred to Hellenic
Geodetic Reference System of 1987 (HGRS87) that is based
on GRS80 reference ellipsoid with a 6,378,137.000 and
1/f 298.257222101. The projection is Transverse Mercator with central meridian o 24°. The distribution of
orthoimage tiles at the scale of 1:5 000 is predefined. Each
orthophoto tile either historical or current encompasses a
geographic area of 12 km2 (4,000 m 3,000 m).
Forest Mapping
In current forest mapping projects and therefore in this
paper, forests, forestlands, and forested areas are considered
as a continuous type of land and referred as “forestlands.”
These lands are dominated by dense or sparse, woody or
shrubby vegetation, including rocks, barren, alpine, or open
lands within these three categories (Government Gazette
No. A-289, 1979).
The process of digital forest mapping aims at the development of forestland database and associated Forest Maps as a
final product. A Forest Map combines the reference background orthoimage with the boundaries of forestlands along
with their characterization. The Forest Map design includes
a series of steps outlined in Figure 2. Forest Map design
prerequisites, historical digital orthophoto generation, and
orthophotomap design, the so-called “1945(1960) Orthophotomap” (Plate 1). The boundaries of lands are delineated on
orthophotos through historical aerial stereoscopic photointerpretation, resulting in three categories of lands: forest lands
denoted by (), grasslands denoted by (X), and non-forestlands
denoted by (A) (Table 1). Historical mapping of these lands is
enforced by Law No. 2664/1998 to fulfill the constitutional
provisions of Article 117.
The boundaries of current forestlands are delineated on
the recent orthophoto dataset based on recent aerial stereoscopic photointerpretation and field visits. Photointerpretation results are validated on the ground by foresters and
against additional data sources, which determine land
status (forest/non-forest) and associated state property
rights. These sources include existing administrative deeds
issued by the local Forest Service over time, available
historical cadastral forest maps produced in 1976, and
historical land distribution diagrams. Deeds refer to legal
forestland status such as: (a) granting of public forestlands
for use or property, (b) reforested lands, (c) forest/nonforest, and (d) grassland. In most cases, they are accompanied by sketches or extracts of topographic maps (scale
of 1:5 000) along with land boundaries and have to be
re-engineered and positioned on recent orthophotos. Historical land distribution diagrams (scales ranging between
1:2 000 and 1:5 000) from the 1930s to 1960s are used to
identify current forestlands that have not been distributed
to citizens for agricultural use. The above data are digitized
and converted to HGRS’87 to comprise additional layers of
information. The respective lands categories are properly
attributed and presented in Forest Maps with a special
symbol designation.
A classification scheme based on a combination of the
current and historical land categories is adopted to provide
the details on land status over time. The scheme resulted in
12 land categories (Table 1).
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Figure 2. Diagram showing the sequential steps
involved in Forest Map development.
In some instances, the position of a forestland boundary
is not precise or where the land-cover characterization is
uncertain on historical orthophotos due to shadows and low
radiometric quality of aerial photos or mixed land-cover
types, respectively. In such cases, information provided by
current land-cover mapping is used as ancillary means of
facilitating historical forest mapping. Ordinarily, time series
of remotely sensed images are utilized to study successive
stages of vegetation cover for its proper classification in the
past, since interpretation of historical aerial photos cannot
be assessed on the ground. This approach was not adopted
because it would require additional time and cost for air
photo reproduction and forestland photointerpetation.
As soon as boundary delineation and land status are
determined in both time stages, the two digital vector
datasets are integrated in a GIS environment and processed
to provide the digital Forest Map. Prior to spatial analysis,
all line segments are assigned a unique code and symbol
based on the land category they enclose, according to
technical specifications (Government Gazette No. B-1352,
1999). Desktop GIS software (e.g., ArcInfo®, AutoCad® Map,
IRAS-C/Microstation®) is used to spatially overlay the
produced multitemporal vector data superimposed on the
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January 2008
recent georeferenced orthoimage tiles. This simultaneous
analysis of multitemporal data provides a high level of
information regarding the magnitude and nature of a landcover change.
This approach results in differences between the two
mapping phases that occurred due to: (a) real changes at the
land-cover, and (b) boundary shifts due to different geometric accuracy of the two vector data sets. Several sliver
polygons are generated along the edges of current polygons
with variable areas, since a minimum mapping unit (MMU)
area is not yet defined. A MMU area of 0.1 ha is recommended as appropriate to improve classification and simplify edge matching. The geometric shifts are edited following the principle of proximity: if an historical forestland
boundary lies less than 10 m from the current boundary,
then it is moved to the position of the current boundary.
We accept that the current forest boundaries have greater
geometric accuracy than historical ones. Detected changes in
land-cover are recorded and coded according to classification scheme. Sources of error included differentiating
between: (a) olive trees and pine-dominated mixes (Attica
region), (b) olive trees and evergreen broadleaved shrubsdominated mixes (Crete, Ionian Islands), (c) openings within
forested areas, and (d) abandoned fields which have been
naturally forested. A major implementation issue was the
integration of administrative deeds in terms of georeferencing and content, since in many cases their area did not
comply with the photo interpretation results.
The approach results in a preliminary map, the “Recent
Orthophotomap” and the main project output, the “Forest
Map” (Plate 1). The major difference between these two
deliverables refers to their content, that is, the presence
or absence of grasslands which are included in Recent
Orthophotomaps, but not in Forest Maps.
The digital vector data of the above three map types are
delivered in DXF and the exported file format of the GIS
software used in the manipulation and analysis of data,
while the non-spatial data are stored in relational databases.
The basic spatial object in the final database is polygon.
The associated attribute information stored for each polygon
refers to its area, administrative division, land category (past
and current), reference related to images (aerial photography
number and orthoimage tile), and centroid coordinates
(X, Y ). Each polygon is characterized by a 12-digit unique
identifier, which is based on the administrative division of
the country. File naming conventions for each vector or
raster file have been applied to allow for data searching.
The accuracy of the produced Forest Maps was assessed
independently using the life-long experience of local Forest
Services. Forest Maps, plotted at 1:5 000 scale, along with the
associated digital/hardcopy data (aerial photos, orthoimages,
DTMs, databases, etc.), are delivered to local Forest Services for
evaluation of land status characterization (forest/non-forest)
and boundary positional accuracy (Green and Hartley, 2000).
This is accomplished by stereo photointerpretation, field
visits, and validation of existing administrative records (deeds,
historical forest cadastral maps, etc.). According to inspection
results, contractors are obliged to make the respective corrections and re-deliver the Forest Maps.
At this stage, local Forest Services were able to officially
submit the State declaration of property rights in forestlands
to cadastral offices, even though final Forest Maps have not
been produced yet. The lack of final Forest Maps and legal
documentation of private property rights in many areas
across Greece resulted in disputes between state and private
claims over forest and public lands during cadastral processing of property rights. These disputes were resolved by
independent cadastral committees, but caused significant
delay to HCP implementation.
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Plate 1. Main forest mapping deliverables of an area in Prefecture of Imathia: (a) Historical Forest
Orthophotomap (1945), and (b) Forest Map. Maps developed on behalf of KTIMATOLOGIO S.A. by
Isiodos, Ltd and Geoanalysis S.A.
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TABLE 1. CADASTRAL FORESTLAND CLASSIFICATION SCHEME
Map
Land Category
FOREST MAP
RECENT ORTHOPHOTOMAP
HISTORICAL FOREST
ORTHOPHOTOMAP
(1945/1960)
Label
Forestlands in historical aerial photos
Grasslands or rocks in historical aerial photos
Non-forestlands in historical aerial photos
Forestlands in historical and recent aerial photos
Non-forestlands in historical aerial photos: Forestlands in
recent aerial photos
Forestlands in historical aerial photos: Non-forestlands in
recent aerial photos
Reforested lands
Forestlands according to administrative deeds
Non-forests lands according to administrative deeds
Groves and parks in urban areas
Forestlands according to archival records of Forest Service
Non-forestlands
Grasslands or rocks in historical and recent aerial photos
Grasslands or rocks in historical aerial photos:
Non-forestlands in recent aerial photos
Grasslands or rocks according to administrative deeds
The volume of geospatial data produced by cadastral
forest mapping can be served as a data foundation for
building the national digital forestland database. The core
data will contain the following basic spatial data collected
under this project: (a) multi-dated digital orthoimages,
including digital aerial photo datasets, ( b) digital vector
feature data for the themes of all land classes, administrative
boundaries, shoreline, and orthoimage tile boundaries,
(c) elevation data such as DTMs and contours to support the
geometric correction of imagery and three-dimensional
perspective views, and (d) geographic names for physical
geographic features, such as cities, mountains, islands, etc.
Data characteristics, such as standardized content,
consistent resolution, spatial reference system, and consistency comply partially with those of the USGS program,
entitled “The National Map” (USGS, 2001). With advances
in technology, this basic spatial data can be completed,
upgraded, and evolved into a national forestland information
system to meet the national needs for effective forestlands
management, environmental protection, and community
and economic development. The initial concept has been
already developed by USGS and other organizations but it
can be refined and adjusted to Greek environment (Kelmelis
et al., 2003).
X
A
A
A
AN
A
A
BI
AA
XX
XA
X
associated boundaries were previously checked and authorized by the local Forest Service. Categories based on the
classification scheme described previously were aggregated
to form the following general land-cover types (Figure 3):
(a) forestland to forestland, (b) forestland to other use,
(c) grassland to grassland, (d) grassland to other use, and
(e) other use.
Monitoring of Forest Land-cover Change
A central premise of the project is the use of a geographic
data framework for providing unbiased estimates of forestland area and changes. Specific answers to these questions
in local scales were not available until recently, due to lack
of data of sufficient reliability as well as temporal and
geographic detail. An analysis was performed using primary
digital datasets provided by a current forest mapping
contract to investigate changes in forest land-cover over
the past 57 years (1945 to 2002). The study area is located
in northern Greece between the city of Thessaloniki and
Mount Chortiatis encompassing an area of 17,527 ha
covering six municipalities (Figure 3). In the central and
northern part, the areas are mountainous and forested. In
the south, they are mostly rural. In recent decades, population has increased leading to considerable development,
mostly for residential use.
ArcGIS® 8.3 software was used to process the multitemporal land-cover datasets and to map the respective landcover types. The accuracy of land-cover classes and their
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January 2008
Figure 3. Forest land-cover change (1945 to 2002).
A color version of this figure is available at the ASPRS
website: www.asprs.org.
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TABLE 2. AREA
Date of Forest
Mapping
(Year)
Area of
All Lands
(ha)
BY
LAND CATEGORY
Forestlands
Grasslands
Other Use
% of All Lands
1945
54.96
0.74
44.30
56.68
0.68
42.64
With increased attention being given to the conservation
of natural resources and the development of Hellenic Cadastre,
it is hoped that new project initiatives will be soon launched
towards a land register of forests. Priority should be given to
new program areas under cadastral development, peri-urban
areas, where the pressure for land development is extremely
high and to environmental sensitive areas, such as national
parks and wetlands.
17,527,05
2002
References
Table 2 depicts the land classes for the two survey
periods as a percent of all lands that are shown in thousands
of hectares. The relatively small increase (2 percent) of
forestlands is probably due to abandonment of farmlands
within the forested mountainous areas in the north. It is
likely that these farmlands have been converted to forest.
It is worth to note that 3.7 percent of forestlands in 1945
converted to other uses over time, while their spatial distribution spans the entire study area resulting in fragmentation
of forest landscape. Grasslands located mostly in southern
areas have been seriously decreased (by 61 percent), due to
loose protection under the current legal system and local
population needs for residential or rural development.
Results and Discussion
Multi-temporal Forest Maps at the scale of 1:5 000 were
produced at the desired accuracy across the country for a
total area of 768,851 ha (5.8 percent of country area) at an
average cost of $22.80 USD (16.05€) per hectare (Technical
Chamber of Greece, 2005). This cost also includes historical
orthophoto production and integration of administrative
deeds issued by the Forest Service. We found that forestlands occupy an area of 314,653 ha (40.9 percent of total
area), while grasslands cover 41,979 ha (5.4 percent of total
area). The maps provide spatial and highly accurate information on the area and status of forestlands and will serve
as data foundation that could be extended and enhanced
to fulfill the subsequent information needs for land and
ecosystem management.
Aerial remote sensing is a major source of accurate
baseline information on land-cover significant to cadastre
development. Digital orthophotography has substantial
potential for cadastral mapping of forestlands, due to its
high positional accuracy and historical application. It is a
convenient reference framework for registration with other
data sets needed to construct the forestland GIS database.
The forest land-cover change analysis confirmed the
general belief in Greek forest society that forest areas increased
slightly in mountainous areas but not in low altitude areas.
The opposite trend of grassland conversion to other uses
suggests rapid actions for their effective protection. Undoubtedly, more research is needed to study land-cover/land-use
change at different scales in Greece.
The final Forest Map is an indispensable tool for the
effective protection of our natural heritage, an institutional
and administrative instrument for land management and a
foundation towards a land register of forests. Its successful
implementation will allow the Hellenic Forest Service to
concentrate on its mission needs and avoid expending
resources to confirm of whether certain disputed areas
are forests or non-forests. Within the HCP, the Forest
Service is able to defend state property rights in these
lands against third party property claims through Forest
Map development.
PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING
Congalton, R., K. Birch, R. Jones, and J. Schriever, 2002. Evaluating
remotely sensed techniques for mapping riparian vegetation,
Computers and Electronics in Agriculture, 37:113–126.
Decleris, M., 2000. The Law of Sustainable Development: General
Principles, Office for Official Publications of the European
Communities, ISBN 92–828–9287–5, European Commission,
Luxemburg, 145 p.
Duhaime, R.J., P.V. August, and W.R. Wright, 1997. Automated
vegetation mapping using digital orthophotography, Photogrammetric Engineering & Remote Sensing, 63(11):1295–1302.
Government Gazette No. A-6, 1976. About Registration, Property
Records and Delineation of Forest Lands and Protection of State
Forest Lands, Law No. 246, 12 January, Ministry of Agriculture,
Athens, Greece.
Government Gazette No. A-289, 1979. On the Protection of Forests
and Forestal Areas, Law No. 998, 29 December, Ministry of
Agriculture, Athens, Greece.
Government Gazette No. A-275, 1998. National Cadastre and Other
Provisions, Law No. 2664, 03 December, Ministry of Environment, Physical Planning and Public Works, Athens, Greece
(available in English).
Government Gazette No. B-1352, 1999. Technical Specifications for
Forest Map Design, General Directorate of Forests, Ministry of
Agriculture, 01 January, Athens, Greece (available in English).
Green, D.R., R. Cummins, R. Wright, and J. Miles, 1993a. A methodology for acquiring information on vegetation succession from
remotely sensed imagery, Landscape Ecology and Geographic
Information Systems (R. Haines-Young, D.R. Green, and S.H.
Cousins, editors), Taylor and Francis, London, pp. 111–128.
Green, R.D., and S. Hartley, 2000. Integrating photointerpretation
and GIS for vegetation mapping: Some issues of error, Vegetation Mapping: From Patch to Planet (R. Alexander and
A.C. Millington, editors), John Wiley & Sons, Ltd, pp. 103–134.
HEMCO, 1997. Technical Specifications for Hellenic Cadastre,
Edition No. 8, Hellenic Mapping and Cadastre Organization,
Athens, Greece (available in English).
Kelmelis, A.J., M.L. DeMulder, C.E. Ogrosky, N.J. Van Driel, and
B.J. Ryan, 2003. The National Map – From geography to mapping and back again, Photogrammetric Engineering & Remote
Sensing, 69(10):1109–1118.
Luman, D.E., C. Stoher, and L. Hunt, 1997. Digital reproduction of
historical aerial photographic prints for preserving a deteriorating
archive, Photogrammetric Engineering & Remote Sensing,
63(10):1171–1179.
Mas, F.J., A. Velázquez, J.L. Palacio-Prieto, G. Bocco, A. Peralta, and
J. Prado, 2002. Assessing forest resources in Mexico: Wall-to-wall
land use/cover mapping, Photogrammetric Engineering & Remote
Sensing, 68(10):966–968.
Ministerial Circular No. 159140/1077, 1980. Guidelines for the
Practice of Law No. 998/1979, Z’ Directorate for Forest Property,
General Directorate of Forests and Forest Environment, Ministry
of Agriculture, Athens, Greece.
Ministry of Rural Development and Food, 2005. Current status of
Hellenic forestry: Area, distribution and types of forests, URL:
http://www.minagric.gr/greek/2.5.1.1.html (in Greek), Athens,
Greece (last date accessed: 16 October 2007).
National Inventory of Forests, 1992. Results of the First National
Inventory of Forests, Ministry of Agriculture, General Secretary
of Forests & Natural Environment, Directorate of Forest Cadastre,
Athens, Greece, 135 p.
January 2008
45
06-008.qxd
5/12/07
19:21
Page 46
Potsiou, C., M. Volakakis, and P. Doublidis, 2001. Hellenic cadastre:
State of the art experience, proposals and future strategies,
Computers, Environment and Urban Systems, 25:445–476.
Raumann, C.G., M.A. Mathie, D.R. Vitales, and D.K. Adams, 2004.
Development and applications of historical digital orthophotos,
Proceedings of the ASPRS 2004 Annual Conference, 23–28 May,
Denver, Colorado.
Technical Chamber of Greece, 2005. Axes of Strategic and Operational
Planning for National Cadastre Development (in Greek), Hellenic
Association of Rural and Surveying Engineers, January, Athens,
Greece, 120 p.
Teselle, G., J. Plasker, A. Mikuni, and K. Wortman, 1994. A National
Orthophoto Program, Proceedings of GIS/LIS ’94, University of
Maine System Libraries URL: http://libraries.maine.edu/spatial/
contents/proceedings/gislis94.html, (last date accessed:
16 October 2007).
USGS, 2001. The National Map: Topographic Mapping for the
21st Century, U.S. Geological Survey, Reston, Virginia, URL:
http://www.nationalmap.usgs.gov/, (last date accessed:
16 October 2007).
Walstra, J., J.H. Chandler, N. Dixon, and T.A. Dijkstra, 2004. Time
for change – Quantifying landslide evolution using historical
aerial photographs and modern photogrammetric methods,
Proceedings of the XXth ISPRS Congress: Geo-Imagery Bridging
Continents, URL: http://www.isprs.org/istanbul2004/comm4/
comm4.html, (last date accessed: 16 October 2007).
46
January 2008
Wang, H., and E.C. Ellis, 2005. Spatial accuracy of orthorectified
IKONOS imagery and historical aerial photographs across five
sites in China, International Journal of Remote Sensing, May,
26(9):1893–1911.
Welch, R., M. Madden, and T. Jordan, 2002. Photogrammetric and
GIS techniques for the development of vegetation databases of
mountainous areas: Great Smoky Mountains National Park, ISPRS
Journal of Photogrammetry and Remote Sensing, November,
57(1–2):53–68.
Winkler, P., 2004. The national orthophoto program of Hungary
completed under strict quality control, Proceedings of the XXth
ISPRS Congress: Geo-Imagery Bridging Continents, URL:
http://www.isprs.org/istanbul2004/comm4/comm4.html (last
date accessed: 16 October 2007).
Wolf, P.R., and B.A. Dewitt, 2000. Elements of Photogrammetry with
Applications in GIS, McGraw-Hill, Boston, 609 p.
WWF Hellas, 1999. Campaign “Forests for Ever”, Newsletter, February,
WWF Hellas, Athens, Greece.
Zentelis, P., and E. Dimopoulou, 2001. The Hellenic Cadastre in
progress: A preliminary evaluation, Computers, Environment
and Urban Systems, 25:477–491.
(Received 18 January 2006; accepted 21 April 2006; revised:
07 June 2006)
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