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Geographic Information System for Arctowski Station
A
Geographical Information System (GIS) of Arctowski Station and
SSSI No. 8 base on topographic surveys carried out during the XXV
Antarctic Expedition (2000/2001) organized by the Department of
Antarctic Biology, Polish Academy of Sciences. The
area presented in the map (Fig. 1 and Pudełko 2002) is a subject of
rapid glacier range changes. This becomes apparent when comparing this
study with the earlier maps (Furmańczyk and Marsz 1980, Battke 1990)
and measurements (Kejna et al.
1998, Battke et al. 2001,
Birkenmajer 2002). The
greatest changes were recorded in
the vicinity of Bastion and close to Ecology Glacier forehead. Bastion
and The Tower were nunataks
some years ago (Battke 1990). The
Site of Special Scientific Interest No.8 (SSSI No.8) was created by the
Antarctic Treaty Consultative Parties in 1979 and it is based on
a Polish proposal.
Diverse avian and mammalian species as well as locally rich vegetation
provide a representative sample of marine Antarctic ecosystem. The
management of the SSSI No 8 aims at protection of bird colonies and seal
breeding grounds against unnecessary and potentially damaging human
activities. The
Geographic Information System used to automate, manipulate, analyze and
display geographic data in digital form. Therefore GIS creation should
be consider as main aim of the survey. The GPS surveys were the main way
of gathering topographical data.
Fig.
1. The draft shows location of GPS survey and range of GIS project. GPS survey and methods of preparing GIS data
Preliminary
study for using kinematical GPS survey for gathering topographic data on
this area was done during the XXIII Antarctic Expedition (summer season
1998/1999). It was the first data which had been stored in the GIS
manner. There was a 1:5000
scale topographic map of the neighborhood of Arctowski Station
and the front of Ecology Glacier (unpublished) made as well. Apart from
the topographic map there was made many thematic drafts concerning 1)
small glacial forms (before front of Ecology, see Fig. 2), 2) range of
plant clusters, 3) penguin colonies. All information has been put into
the GIS project. The
field surveys were carried out using double frequency GPS receivers
Ashtech Z-12. The first one, with a fixed location, served as a base
receiver. The second one, after an introductory 10-minute initialization
(this is required for resolving the carrier phase ambiguity),
was carried into the field to gather information at 15-second interval.
Co-ordinates of points (X,Y, Z) obtained during the field survey were
subsequently calculated using PNAV application. Precision of the
measurements has been estimated as better than 10 cm. Essential
conditions of the correct measurements were: observations of at least 4
satellites by two receivers, and PDOP index below 4.0 (Pudełko 2003). There
were about sixteen thousand points measured during the XXV Antarctic
Expedition (summer season 2000/2001). The measurements were carried out
in such a way to allow the determination of the range of objects
(including creeks, lake borders, ice ranges, ridges, shorelines, etc.)
and to achieve density of the point cover sufficient to interpolate
contour lines. For a few objects, the GPS measurement was impossible to
be obtained because of the loss of contact with 4 satellites (under
cliffs and rocky walls), or because of difficult terrain (glacial
crevasses, ridges). In these cases, the measurement gaps were filled by
analyses of aerial photos
(made by Furmańczyk in 1979) and theodolite measurements. All
data were put to the Geographic Information System for further edition.
Collected GPS data were then processed using ArcView. The
geographical co-ordinates were projected to Transverse Mercator. The
main tasks were extraction the shape of objects and contours
interpolation (10 m interval) from the huge set of points. All the
extracted objects were classified to the vector layers (Shape format –
SHP). Aerial
photos were rectified by Erdas Imagine. Apart from filling the
measurement gaps archival photos were used for evaluation of the changes
of the glaciers range and other geomorphologic forms. The ice border in
1979 was determined and put into the GIS. GIS
project The
system has been designed for ArcView (ESRI product) – the most
popular desktop of GIS. The project use two kinds of spatial data:
vector and raster. Chosen formats
of spatial data guarantee easy export/import between different GIS
applications. Vector
data are stored
in SHP format. The total size of vector data is about 4.2 MB (with dbf)..
There are three kind of vector data: points, lines, polygons 1.
glaciers - polygon layer that describes glacier’s system 2.
dead ice zones - polygon layer, zones have been labeled by their
area 3.
ponds - polygon layer; there are 36 ponds in this layer but some
of them could disappeare in short time as a result of geomorphological
changes, 4.
Adeli colonies - polygon layer that describes range of Adeli
colonies. Each colony has been labeled by its area, 5.
rocks - polygon layer that describes range of rocks which are
impossible to characterize by contours; bigger rocks are labeled by
their names. 6.
contours - layer that contains contour lines with 10 m interval
(labeled to line); range of lines are the same like range of the
1:12,500 scale topographic map, 7.
creeks - line layer, some of creeks are labeled by their names 8.
borders - line layer that describes borders of ice, coast and
SSSI No. 8 9.
elevation points - point layer that describes characteristic for
elevation places (tops, passes) and GPS stations. Each point has been
labeled by its altitude and short description, 10.
marked points - point layer that describes labeled or unlabeled
wooden or steal pools. Each object has been labeled by its number,
elevation and short description, 11.
other objects which could be described as a point - layer that
describes different objects e.g. station’s and refuge’s location,
caves, grave, etc. Each object has been labeled by its name and short
description. Raster
data. Continuous
surfaces and digitalized maps are stored in GeoTiff file format. The
total size of raster data is about 20 MB.
There are two digitalized, rectified maps (1:5,000 and 1:12,500)
and DEM (digital elevation model). DEM was modeled in Arc/Info
with Topogrid method. Its resolution is 10 meters and a range is
the same as range of the 1:12,500 scale topographic map (Pudełko 2002).
Data
base. Most of the
objects are linked to the database. DBF files are related to SHP files
via common name. The users of the project can get names of chosen
objects and other features. Depending on kind of the objects there could
be area, perimeter, altitude etc. These feature were obtained as a
result of GIS analysis. The names used for describing objects in the GIS
project based on the existing topographical maps. Names on Battke
(1980,1990), Furmańczyk and Marsz (1980) and Pudełko’s (2002) maps
were taken from Birkenmajer (1980, 1998), who introduced them in 1977/78
and 1978/79 (see Birkenmajer 1979). During the survey thirteen new names were introduced and one was changed (Pudełko
2003).
Fig
2. GIS for Arctowski Station. Vector data
Free GIS for Arctowski - instant to use If you want to download data send e-mail:
Step 1. Download the project (apr) and shape files (1.39 MB) Step 2. Download the raster, 1:12500 topographic map, (1.55 MB) Step 3. Put both arc-vec.zip and arct.tif.zip to c:\arctowski on your hard disc and unzip Step 4. Start ArctView 3.2 with arct.apr or import arct.apr to ArcGIS
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