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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 There  was a 1:5000 scale topographic map of the neighborhood of Arctowski Station and the front of Ecology Glacier (unpublished) made as well.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
(Fig. 2). The project contains following layers:

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  - ArcGIS

 

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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