Viewshed Analysis and Intersite Visibility of Iron Age Castros in

Viewshed Analysis and Intersite Visibility of Iron Age Castros in Northern Portugal
Jordan Bowers
GEO 386G
Fall 2014
Table of Contents
Introduction ......................................................................................................................................1
Data Acquisition and Modification..................................................................................................2
Digital Elevation Model .......................................................................................................2
Creation of the Geodatabase ................................................................................................2
Study Area Vector Layer .....................................................................................................2
Political Geography of Northern Portugal ...........................................................................3
Hydrogeography of Northern Portugal ................................................................................3
Name and location of Castros ..............................................................................................4
Viewshed Analysis...........................................................................................................................4
Intersite Visibility Analysis .............................................................................................................5
Conclusions ......................................................................................................................................6
Map 1: Castros and Municipalities of Northern Portugal ...............................................................8
Map 2: Viewshed from Cividade de Bagunte .................................................................................9
Map 3: Viewshed and Visible Sites from Cividade de Bagunte ...................................................10
Map 4: High Certainty Intersite Visibility Network of Northern Portugal ...................................11
Map 5: Intersite Visibility Network in Northeastern Portugal......................................................12
Table 1: Castros of Northern Portugal by Number of Sites Visible ..............................................13
Works Cited ...................................................................................................................................16
i
Introduction
The Castro Culture is a culture group from Northern Portugal and Galicia that inhabited the
region from circa 1000 BCE, at the beginning of the Iron Age, until assimilation into the Roman
Empire in the first century CE. The archaeological record is dominated by fortified, hilltop
settlements known as castros. Castros are differentiated in size with three different designations:
Castro, Cividade, and Citania. Cividade and Citania are reserved for the largest castros,
which may cover 25 hectares or more, although these designations are largely up to the
interpretation of the excavators. The core area of the Castro Culture was along the Ave River
and its tributaries in Northern Portugal, but castros have been excavated from the Douro River
to the northern coastline of Galicia. My research in the region is currently over the connection
between visibility and power. I look at the role visibility plays at two levels: at the local
level, particularly with regards to Cividade de Bagunte, and at the regional level covering
the entire area of the Castro Culture. Broader questions I seek to answer are how did a site’s
location permit and secure control over the site’s surrounding landscape and how did a
dominant site’s geographic position relate to other smaller castros within its viewshed?
My dissertation research draws upon the theoretical approaches of both landscape archaeology
and settlement archaeology to create a more accurate understanding of the relationships between
humans, sites, and landscapes. To study the patterns of settlement and use of landscape as an
entangled system unlocks the realities of past boundaries from modern Western perceptions
(Bruck and Goodman, 2003). To consider the concept of boundaries from modern and
prehistoric viewpoints it is imperative to study the taskscape, the nonstatic physical and social
changes that occur in a landscape over time through human labor, which plays a role in the
development of the landscape and one’s interpretations of it (Ingold, 1993). My research focuses
on sites as taskscapes and how the inhabitants of each site utilized the landscape. I am attempting
to understand the ways in which expressions of power and control affect the way the inhabitants
of the site mentally viewed, constructed, and navigated their physical space.
I am applying GIS software as a heuristic tool to understand the processes and conceptions of the
landscape as perceived by an individual (cf. Llobera, 1996). Viewshed analysis and intersite
visibility analysis were necessary for this project in order to begin answering questions about
how visibility plays a role in the expression of power and dominance. In their study of Inca sites,
Kosiba and Bauer have shown that political and social configurations can be expressed by the
location of sites within the physical landscape, particularly by controlling aspects of visibility
(2013). It has been noted that the existence of a visibility network among sites may play a role in
how a site and its inhabitants recreate their environment in response to limitations caused by
natural features, such as ridges (Christopherson and Guertin, 1996). The visibility network
between castros in Portugal has previously been studied (Dinis, 1993), however his study was
limited to a dataset if only 25 castros along the Lower Ave River Valley. My study expands on
the Dinis’s work and includes another 92 castros. I expect to find in this study that Cividades and
Citanias have the largest viewsheds and largest number of sites visible.
1
Data Acquisition and Modification
The data required for this project included:
•
•
•
•
•
Digital Elevation Model for Northern Portugal
Shapefile for the delineation of the study area
Political geography of Northern Portugal, including an outline of the districts and country
and name and locations of municipalities
Hydrogreography of Northern Portugal
Names and locations of castros
Digital Elevation Model
The DEM used for the project came
from publicly available ASTER data. I
set the projection to WGS 1984 UTM
Zone 29N, as this is the same
coordinate system and projection we
use for our field research in the region.
I used the ProjectRaster tool from the
toolbox to apply the projection to the
DEM. This allowed to me to create a
hillshade and to take into account the
curvature of the earth in the viewshed
analysis. Figure 1 shows the DEM
with a stretched color ramp, dark
green showing the lowest elevations
and brown the highest. The DEM
included data for elevations at 0
meters or lower, which was necessary
for creating a vector polygon for the
Atlantic Ocean later on.
Figure 1: DEM from ASTER data
Creation of the Geodatabase
Following the importation of the DEM, it was necessary to create a geodatabase to keep all the
data organized. I created three feature datasets, one each for political geography,
hydrogeography, and the castros. I also created a feature class that would be used to delineate the
study area.
Study Area Vector Layer
After adding the DEM to ArcGIS, I created a polygon within the ‘study area’ feature class that
included all of Portugal north of the Douro River, some areas of Spain, and the Atlantic Ocean. I
then used this layer as a mask to clip the DEM to the study area. This polygon was also used as
a mask to clip all of the other data imported in order to ensure that shapefiles would not
extend outside of the study area.
2
Political Geography of Northern Portugal
For the Political Geography feature class, I imported the administrative regions and country
outline downloaded from DIVA-GIS. I found a shapefile for all municipalities in Portugal from
MapCruzin.com. I edited this shapefile in order to only show the largest towns within the
districts in Northern
Portugal
and
corrected
many
errors caused by
special characters in
the names. Figure 2
shows the modified
shapefiles for the
political geography
of
northern
Portugal, The thick,
gray
outline
represents
the
outline of Portugal,
the thinner lines are
the borders for the
districts, and the
points are for the
municipalities.
Figure 2: Modified shapefiles of the political geography of Northern Portugal
Hydrogeography of Northern Portugal
From the DEM, I created a raster of
the Atlantic from all elevations which
were less than or equal to zero, which
was then converted into a vector layer. I
then edited the Atlantic Ocean vector
to clean up some of the irregularities
that remained from the DEM, then
used the Dissolve tool to further clean
up the layer. I then imported shapefiles
for the rivers and lakes in Portugal
that I downloaded from DIVA-GIS.
These shapefiles were overly simplified
and when zoomed in did not match up
with the valleys in the DEM. I used
LandSat
imagery
to
edit
these
shapefiles to create more accurate lines for
the rivers and polygons for the lakes.
Figure 3: Shapefile showing the Atlantic Ocean and the modified rivers
and lakes
3
Name and Locations of Castros
To find the longitude and latitude for the castros in Portugal and Galicia, I used two main
sources, “Ordenamento do Territorio do Baixo Ave no I Millenio A.C.” by Antonio Pereira Dinis
and Megalithic.co.uk. Dinis gives the names and locations for 25 castros along the Lower Ave
River Valley, although he does not state which datum he is using for his coordinates. However,
when projected using the WGS84 datum, these sites appear to fall in the correct location, so it is
probable that this is the datum he used. To get data for other castros within Portugal,
Megalthic.co.uk contained names and coordinates for many other sites, however I am unsure of
the accuracy of the coordinates given for each site. A spreadsheet (see Table 1, p. X) containing
the listing of sites and their coordinates was imported using the ‘Import XY Data’ function and
were then added to the feature dataset ‘castros’. The collection of these data allowed me to create
a map of castros in Northern Portugal in relation to the political and physical geography of the
region (see Map 1, p. 8).
Viewshed Analysis
The viewshed analysis tool in ArcToolbox was applied to each site within the study area. This
tool identifies all cells visible from a particular point on a projected DEM raster and can even
take into account refractivity and earth curvature, which was necessary because the study area
was so large. The viewshed analysis results in a binary raster where 0=not visible and 1=visible.
The tool was unable to run for all
castros within the study area and
return individual results for each site.
This made it necessary to create
individual point feature classes for
every site, after which each site had to
be run through viewshed analysis.
Figure 4 shows an example of how I
used the Viewshed tool for each site.
On the attribute table for each site
point I added the column ‘OFFSETA’
and entered a value of five meters.
This meant that when the viewshed
tool was running it would calculate
the observer point as being five
Figure 4: Example of viewshed tool as applied to each site
meters higher than the elevation of the
cell. I decided to use an offset value in order to see the viewshed as it would be seen from the top
of a wall or watchtower, as opposed to within the actual site where one likely would have not
been able to see outside the site. The result was an individual binary raster for each site showing
which cells on the DEM were visible or not from the theoretical watchtower.
4
For each raster, I changed the
symbology to only display the cells
that are visible and set them to 60%
transparency so that overlap of
viewsheds would be visible. The
overlap is currently not important
for my research, but may be
beneficial in answering later
questions that may come up
regarding areas of shared visibility.
I then gave each raster a unique
color in order to differentiate the
visibility for each site. There is
some possible overlap in colors, as
applying 117 distinct colors is a bit
difficult, but showing and hiding
the various layers can assist in
differentiating viewsheds with
similar colors. Figure 5 shows a
combination of all viewshed
rasters, which gives an overall idea
Figure 5: Viewshed for all castros in Northern Portugal
of the total extent of visible areas
from all sites. Map 2 (p. 9) shows the viewshed for only Cividade de Bagunte, including other
visible sites. A future goal from this research is to calculate the total area visible from each site,
however the DEM will need to be refined before an accurate number can be achieved
Intersite Visibility Analysis
From the results of the viewshed analysis, I created a new line feature class for intersite
visibility. This layer shows lines between sites that mark the visibility between castros. I
categorized the lines into two types based on the certainty of the visibility. The certainty for each
line came from the location of sites in conjunction with the viewshed. When testing for visibility,
if a site fell within the areas marked as visible in the viewshed raster I marked it as having high
certainty. If the site was separated from visible areas, but only by a few cells, I assigned the low
certainty attribute to the line.
Map 3 (p. 10) shows the results of the visibility analysis for only Bagunte in combination with
the viewshed raster. The results of this analysis for a single site mirrors the results of the
viewshed analysis, but only as the viewshed relates to other sites. Combining the lines for
intersite visibility for all sites within the study area a clear network of visibility forms (see Map
4, p. 11). The sites in Northwestern Portugal form one grouping with a high level of connectivity,
as shown in Map5 (p. 12). This grouping is distinct from the sites in Northeastern Portugal,
which show some connectivity, but many of the sites are not visible from each other. It is
possible from this analysis to question the validity of classifying the sites in the eastern portion
of the study area as being part of the Castro Culture, however it is also necessary to include
material culture if a distinction is to be made.
5
Conclusion
It is necessary to expand upon this project in the future. There are a number of issues related to
the data, particularly from the DEM and castros, that could cause results of the analyses to
change. It appears that the DEM includes buildings and foliage in its measurements of elevation.
This means that a stand of trees may block a large section of the viewshed now, whereas this
may not have been the case during the Iron Age. Additionally, many of these sites are
surrounded by tall eucalyptus trees, which would also limit the viewshed from the acropolis of
each site. This was the case at Bagunte, where I had to find the highest elevation and move the
observer point there in order to get a better result from the viewshed analysis. The issues
stemming from the ASTER DEM can be rectified through using other sources of information for
elevation, such as topographic maps or LIDAR data. I will also be performing research during
upcoming field seasons on pollen and phytoliths dating to the Iron Age. The results of this
research should give a better idea of what species of plants, particularly trees, were growing in
the region and at what density. The difference between thick forests and open plains can vastly
change a viewshed, and thus the visibility network between sites, so it will be necessary to take
this into account.
The list of castros and their coordinates may also have caused some errors in the data. Many of
these coordinates were collected from the internet and the accuracy of them is unknown. Many
of the coordinates were not accurate enough to place a point exactly where the site would be.
Rectification of this would require that each site be visited and its coordinates remeasured. It is
also possible that the list is incomplete. Dinis’s listing only gives coordinates for castros in the
valleys of the Ave and Este Rivers. Additionally, the Megalithic Portal does not appear to have a
complete listing of castros for Portugal and it is possible that many outside of the area discussed
by Dinis were not included in this analysis. Map 1 highlights this discrepancy, as a clear
concentration of sites is evident along the Ave River and only a few appear north toward Spain.
The results of these GIS analyses offer insight into the role that visibility played within the
Castro Culture. There must have been a reason for these societies to settle along hilltops. There is
little to no evidence for war or battles between the castros, but the geographic position of the
settlements in combination with large walls points at the need for the culture to settle in easily
defendable areas. The intersite visibility analysis highlights the connection between almost all of
the settlements commonly identified with the Castro Culture in Portugal. The vast network
would allow information to be exchanged quickly between settlements.
Table 1 lists the castros included in the study area. Columns are included with the number of
sites visible from each location, which is then broken down to the number of sites where the
certainty of visibility is high and low. The results of this backed up my expected results that
Cividades and Citanias would have the greatest number of sites visible. However, there were a
few unexpected results. Monte da Falperra was much higher than expected, with 31 total sites
visible and also had the greatest number visible with high certainty (22). Equally surprising was
the position of Citania de Briteiros. Briteiros is one of the largest and best well documented
castros in Portugal, however the number of sites visible from it was much lower than expected.
Following with the idea that Citanias and Cividades would have the highest number of sites
visible, it is surprising the Citania da Longa had absolutely zero visibility. However, the location
6
of this castro may lend itself to part of a network of Galician castros. It is also possible that
Longa was designated as a Citania due to sociopolitical factors when these sites were first
excavated. A continuation of this project will be necessary to get at the larger questions
regarding visibility, power, and control, but refinement of the data used to draw these inferences
must occur in order to improve the accuracy of the results.
7
Map 1: Castros and Municipalities of Northern Portugal
Pontellas
Baiona Xián
Spain
ho
Mi
42°0'0"N
8°0'0"W
Troña
7°30'0"W
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)
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)
"
)
"
)São Caetano
io
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im
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"
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"
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)
"
)
"
)
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"
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"
)
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"
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"
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"
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"
"
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"
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"
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"
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"
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41°30'0"N
"
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)
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"
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our Resende
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io D
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"
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"
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"
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"
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Alfandega da Fe
"
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)
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Carrazeda de Ansiaes
41°0'0"N
WGS84 UTM Zone 29N
1:750,000
8°30'0"W
¹
"
)
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20
8°0'0"W
30
40
7°30'0"W
50
Kilometers
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)
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"
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Atlantic
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9°0'0"W
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"
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Meda
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7°0'0"W
41°0'0"N
"
)
Castros
Rivers
Country Border
Municipalities
Lakes
District Border
9
Map 2: Viewshed From Cividade de Bagunte
8°30'0"W
"
)
8°0'0"W
) Coto de Ouro
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"
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"
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"
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"
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"
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"
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"
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a
"
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"
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41°30'0"N
"
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"
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7°30'0"W
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5
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io
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20
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District Border
Km
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Visible Areas
WGS84 UTM Zone 29N
1:325,000
10
Map 3: Viewshed and Visible Sites from Cividade de Bagunte
8°30'0"W
Vila Real
) Alto das Valadas
"
Tras de Cidades Cresto
)
"
)
"
Viana do Castelo
)
"
8°0'0"W
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"
) Roques
"
Sabariz
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Redondo
) Carmona
"
) Castelo do Neiva
"
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"
Braga
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ado
av
) Máximo
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41°30'0"N
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ste
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)
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"
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"
)
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"
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"
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) Facho
"
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"
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"
Rio Viz ela
) Torre Alta
"
) Santa Margarida
"
) Sanfins
"
) Monte Padrão
"
) S. Paio
"
Bagunte
) Sabroso
"
) S. Miguel-o-Anjo
"
) Bóca
"
S. Miguel-O-Anjo
)
"
Cruito
) Alvarelhos
"
Monte Castelo
Falperra
) Briteiros
"
)
"
) S. Bartolomeu
"
) Forca
"
) Boi
"
¹
) Nandunfe
"
Consolação
Pedrais
)
"
) Lages
"
Retorta
)
"
)
"
41°30'0"N
) Santa Maria de Galegos
"
) São Lourenço
"
) Vasoncelos
"
)
"
) Monte dos Picos
"
)
"
ve
) Nossa Senhora da Paz
"
) Monte do Castelo
"
) Eiras Velhas
"
) Monte Castro
"
Porto
)
"
)
"
Torroso
Lakes
) Serra do Muro de Vadoma
"
8°30'0"W
District Border
Visible Areas
0
5
10
High Certainty
20
Km
8°0'0"W
Low Certainity
8°50'0"W
Map 4: High Certainty Intersite Visibility Network of Northern Portugal
8°40'0"W
8°30'0"W
8°20'0"W
8°10'0"W
8°0'0"W
7°50'0"W
7°40'0"W
7°30'0"W
Mi
nh
R
io
) Alvora
"
) Cossourado
"
Pintán
)
"
)Santa Tecla
"
)
"
Coto da Pena
São Martinho
) Coto de Ouro
"
Viana do Castelo
41°50'0"N
) Formigoso
"
) Ancora
"
) Coroa
"
Li
Rio
) Vieito
"
ma
" Alto
)
Tras de Cidades Cresto
Sabariz
) Roques
) "
"
41°40'0"N
"Castelo do
)
) Belinho
"
)
"
)
"
im
Rio L
41°50'0"N
a
) Pedrario
"
) São
"
das Valadas
) São
"
Barbudo
) "
"
)
Redondo
) Carmona
"
Neiva
Monte Castro
Máximo
)
"
)
"
) São Lourenço
"
Ferreiros
)
"
)
"
)
"
Julião
8°50'0"W
)Cabeço
"
)
"
) Lesenho
"
) Monte
"
Velhas
Santiago do Monte
) Vilarendelo
"
) Vilanova
"
) Loivos
"
)
"
) Giestosa
"
) Eiras
"
)
"
do Castelo
) Ribas
"
Vila Real
)
)"
"
)
) "
"
Alto
41°40'0"N
41°30'0"N
) Cerva
"
) Palheiros
"
) Crastoeiro
"
) Populo
"
Bragança
41°20'0"N
Porto
)
"
Torroso
) Serra
"
)
"
R io D
do Muro de Vadoma
) Monte
"
ro
ou
¹
Lama de Ouriço
)Guedes
"
8°40'0"W
WGS84 UTM Zone 29N
8°30'0"W
Scale: 1:550,000
8°20'0"W
Mozinho
" Arados
)
)
"
8°10'0"W
District Border
uro
) Cidadelhe
"
41°10'0"N
Do
Monte Castelo
)
"
Romão
Cavalhelhos
) Nandunfe
"
do Crasto
Braga
Pedrais
) Briteiros
"
)
"
)
"
) Picotos
"
) Sabroso
"
) Lages
"
S. Bartolomeu
)
"
) Forca
"
)
)
"
) Santo Ovidio
"
) Saia "
"
) Bóca
"
)
"
) Alto das Eiras
"
)"
"
)
"
Penices
Terroso
Cruito )
) Santa Tecla
"
)
"
)
"
Casais
) Facho
"
) S. Miguel-o-Anjo
"
)"
"
)
) Bagunte
"
Retorta
Santogões
)
"
)
) Torre Alta
"
) "
"
)
"
) Santa Margarida
"
Santa Marinha
S. João
) Sanfins
"
) Boi
"
)
"
Monte Padrão
) Alvarelhos
"
) S. Paio
"
41°20'0"N
41°10'0"N
) Azere
"
) Cendufe
"
)
"
41°30'0"N
7°20'0"W
)
"
o
)
"
11
Ri o
8°0'0"W
Lakes
0
5
10
7°50'0"W
Rivers
Viseu
20
7°40'0"W
)
"
)
"
Castros
30
7°30'0"W
40 Guarda
Km
7°20'0"W
High Certainty of Visibility
)
"
Map 5: Intersite Visibility Network of Northeastern Portugal
8°50'0"W
8°40'0"W
)
"
41°40'0"N
8°30'0"W
) Roques
"
Sabariz
) Barbudo
"
)
"
Redondo
do Neiva
) Belinho
"
) Nossa
"
) Monte
"
Senhora da Paz
) São
"
) Eiras
"
Castro
) Santa
"
Lourenço
) Sr.
"
Maria de Galegos
)Máximo
"
Alto da Cividade
dos Desamparados
)
"
) Ferreiros
"
) Alto
"
do Crasto
) Consolação
"
) Falperra
"
) Picotos
"
) Ermidas
"
Rio
Est
e
)
"
) Alto
"
e
Santa Cristina
)
"
)Penices
"
" Casais
)
)
"
Argifonso ") Bagunte
41°20'0"N
Atlantic
Ocean
) S.
"
¹
8°50'0"W
WGS84 UTM Zone 29N
Scale: 1:250,000
) Santogões
) Retorta "
"
João
)Santa
"
) Facho
"
41°30'0"N
o
Bartolomeu
) Forca
"
Miguel-o-Anjo
) Santo
"
Ovidio
das Eiras
) Vermoim
"
)
"
) Terroso
"
) S.
"
) Bóca
"
S. Miguel-O-Anjo
Cruito
)
"
Av
Ri
) S.
"
) Saia
"
dos Picos
" Pedrais
)
) Sabroso
"
) Lages
"
41°30'0"N
)
"
) Briteiros
"
o
a vado
Monte do Castelo
Velhas
) Vasoncelos
"
) Monte
"
)
"
Ri
C
8°10'0"W
41°40'0"N
) Carmona
"
) Castelo
"
8°20'0"W
)
"
12
) S.
"
) Santa
"
Tecla
Miguel-o-Anjo
Rio Vize l a
) Torre
"
Marinha
Alta
) Santa
"
Margarida
41°20'0"N
) Boi
"
) Monte
"
) Alvarelhos
"
) S.
"
0
Paio
8°40'0"W
District Border
) Sanfins
"
Padrão
Lakes
8°30'0"W
Rivers
5
8°20'0"W
)
"
Castros
10
High Certainty of Visibility
20
Km
8°10'0"W
Low Certainty of Visibility
Table 1: Castros of Northern Portugal by Number of Sites Visible
Site
Latitude
(DD)
Longitude
(DD)
Number of
Sites Visible
High
Certainty
Low
Certainty
Monte da Falperra
41.513889
-8.393333
31
22
9
Cividade de Bagunte
41.385556
-8.654444
24
17
7
Monte da Saia
41.457222
-8.583611
23
13
10
Citania de Sanfins
41.323333
-8.386667
21
17
4
Castro do Facho
41.404444
-8.545833
16
4
12
Castro do Alto das Valadas
41.714142
-8.598734
14
13
1
Castro de S. Miguel-o-Anjo (Ruivães)
41.399722
-8.425000
14
10
4
Castro de Carmona
41.646887
-8.648413
14
7
7
Castro de São Lourenço
41.556111
-8.761667
13
12
1
Castro de Barbudo
41.652677
-8.470149
13
10
3
Castro de Alvarelhos
41.300556
-8.619444
13
9
4
Monte dos Picos
41.568333
-8.332500
13
8
5
Castro de Consolação
41.550278
-8.384444
13
6
7
Castro do Monte Padrão
41.314722
-8.447500
13
6
7
Monte de S. Bartolomeu
41.478056
-8.381667
12
10
2
Cividade de Terroso
41.414167
-8.719722
11
7
4
Castro de Santa Tecla
41.416944
-8.402222
11
6
5
Castro de Lages
41.498333
-8.448056
11
4
7
Alto da Cividade
41.545000
-8.427500
10
9
1
Alto do Crasto
41.554722
-8.365833
10
9
1
Citania de Sabroso
41.512462
-8.341603
10
6
4
Citania de Briteiros
41.527500
-8.316111
10
6
4
Castro Máximo
41.561205
-8.428103
9
8
1
Castro da Serra do Muro de Vadoma
41.199396
-8.390364
9
7
2
Citania de São Julião
41.689418
-8.393889
9
6
3
Eiras Velhas
41.585000
-8.342222
8
7
1
Castro de S. Miguel-o-Anjo (Vermil)
41.460000
-8.383889
7
7
0
Pedrais
41.517778
-8.350278
7
7
0
Monte de Vasoncelos
41.575556
-8.376389
7
5
2
Monte da Forca
41.469444
-8.367778
7
5
2
Monte do Castelo
41.585000
-8.097000
7
5
2
Castro do Sr. dos Desamparados
41.541040
-8.735733
7
4
3
Castro de S. João
41.354167
-8.738333
7
3
4
Castro de Monte Castro
41.584000
-8.633000
6
5
1
Castro de Santa Cristina
41.427222
-8.462222
6
4
2
Pau de Bandeira
41.563611
-8.341667
6
3
3
Santa Maria de Galegos
41.568014
-8.570444
6
3
3
13
Castro da Bóca
41.456111
-8.473333
5
5
0
Castro do Boi
41.322500
-8.675000
5
5
0
Castro de Santa Margarida
41.350000
-8.349000
5
5
0
Monte Redondo
41.649722
-8.441667
5
4
1
Castro das Ermidas
41.461111
-8.522222
5
3
2
Alto das Eiras
41.437778
-8.442222
5
3
2
Castro de Vermoim
41.428333
-8.448611
4
4
0
Castro de Monte Mozinho
41.146389
-8.311111
4
4
0
Castro de Sabariz
41.673653
-8.752824
4
3
1
Castro de Vilanova
41.641441
-7.409367
4
3
1
Cividade De Belinho
41.599936
-8.777198
3
3
0
Outeiro dos Picotos
41.514611
-8.742175
3
3
0
Castro do Vieito
41.730650
-8.807161
3
3
0
Castro de Casais
41.394444
-8.661389
3
2
1
Castro do Cruito
41.431944
-8.469722
3
2
1
Castro de Tras de Cidades
41.711000
-8.633000
3
2
1
Castro do Cresto
41.711000
-8.632000
3
2
1
Monte do Castelo do Neiva
41.614674
-8.786571
3
2
1
Castro de Santiago do Monte
41.675352
-7.461708
3
2
1
Castro de Nandunfe
41.551000
-8.086000
3
2
1
Castro da Retorta
41.359167
-8.722500
3
1
2
Castro do Formigoso
41.787000
-8.649000
3
1
2
Torre Alta
41.355833
-8.475833
3
0
3
Castro de Argifonso
41.391111
-8.656667
2
2
0
Castro de S. Miguel-o-Anjo (Calendário)
41.443056
-8.534444
2
2
0
Castro de São Juzenda
41.603373
-7.156612
2
2
0
Castro de Roques
41.676597
-8.725981
2
2
0
Castro de Lesenho
41.658000
-7.738000
2
2
0
Castro de Fiães
40.988686
-8.519084
2
1
1
Castro de Nossa Senhora da Paz
41.571937
-8.775676
2
1
1
Castro de São Brás
41.654886
-7.121099
2
1
1
Castro da Corôa
41.749000
-8.866000
2
1
1
Castro de Ribas
41.584198
-7.399880
2
1
1
Castro de Ferreiros
41.535833
-8.441667
2
0
2
Castro de S. Paio
41.282778
-8.728889
2
0
2
Castro do Coto de Ouro
41.870887
-8.634000
2
0
2
Castro de Vilarendelo
41.663000
-7.326000
2
0
2
Castro do Guedes
41.110502
-8.568018
1
1
0
Castro de Cendufe
41.813531
-8.487176
1
1
0
Cividade de Ancora
41.786493
-8.854031
1
1
0
Castro de Melgaço
41.086000
-8.278000
1
1
0
14
Castro de Carvalhelhos
41.694000
-7.705000
1
1
0
Castro de Santagões
41.360556
-8.683611
1
0
1
Castro Romariz
40.946185
-8.460331
1
0
1
Castro de Sacóias
41.863127
-6.690234
1
0
1
Castro de Cirigata
41.670252
-6.724291
1
0
1
Castro de São Martinho
41.879000
-8.652000
1
0
1
Cividade do Cossourado
41.915835
-8.637175
1
0
1
Castro do Populo
41.362000
-7.483000
1
0
1
Castro do Pedrario
41.800000
-7.663000
1
0
1
Castro de Palheiros
41.416667
-7.400278
1
0
1
Castro da Lama de Ouriço
41.709000
-7.346000
1
0
1
Castro do Cabeço dos Mouros
40.952000
-8.103000
1
0
1
Muralha das Portas de Montemuro
40.949000
-8.069000
1
0
1
Castro de Santa Marinha de Ferreiró
41.351944
-8.634444
0
0
0
Castro de Penices
41.415556
-8.607222
0
0
0
Castro de Ovil
40.978889
-8.620833
0
0
0
Castro do Monte Valinhas
40.936389
-8.267500
0
0
0
Castro de Santo Ovídio
41.455800
-8.184072
0
0
0
Castro de Gimonde
41.826000
-6.709000
0
0
0
Castro de Aldeia Nova
41.495000
-6.724000
0
0
0
Castro de Vale de Aguia
41.496000
-6.725000
0
0
0
Castro Vicente
41.379000
-6.840000
0
0
0
Castro de Baldoeiro
41.274000
-7.051000
0
0
0
Cabeço de Alfarela
41.199000
-7.051000
0
0
0
Castelo Velho de Freixo de Numao
41.072387
-7.191814
0
0
0
Castro dos Arados
41.098109
-8.277342
0
0
0
Castro do Monte Castelo
41.200405
-8.678481
0
0
0
Castro de Azere
41.865000
-8.405000
0
0
0
Povoado Castrejo de Alvora
41.940862
-8.451105
0
0
0
Coastro do Coto da Pena
41.868000
-8.835000
0
0
0
Castro de São Caetano
42.040556
-8.443611
0
0
0
Castro de Cabeço (Granja)
41.695000
-7.649000
0
0
0
Castro da Giestosa
41.629000
-7.844000
0
0
0
Castro de Loivos
41.626000
-7.510000
0
0
0
Castro de Cidadelhe
41.178611
-7.844444
0
0
0
Castro de Crastoeiro
41.414680
-7.929450
0
0
0
Castro de São Romão
41.983000
-7.588000
0
0
0
Castro da Cerva
41.459626
-7.804879
0
0
0
Citânia da Longa
41.066000
-7.599000
0
0
0
15
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Christopherson, G and D. Guertin (1996). “Visibility Analysis and Ancient Settlement Strategies
in the Region of Tall al-Umayri, Jordan.” University of Arizona. Web. 2 Dec. 2014.
Dinis, A (1993) “Ordenamento do Territorio do Baixo Ave no 1 Milenio A.C.” (Unpublished
doctoral dissertation). Faculdade de Letras da Universidade do Porto, Portugal.
Ingold, T. (1993) “The Temporality of the Landscape.” World Archaeology 25: 152-174
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16