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Fig. 1: Work area of the Research Project SFB 267
The software and hardware environment used for the -
project consists of UNIX workstations linked to a
VAXNMS and a PC pool with the GIS software
ARC/INFO and the digital image processing software
ERDAS/Imagine. These commonly used software
packages guarantee a minimum of data conversion
problems between GIS functions and digital image
processing work. The output media for maps and image
products are an IRIS AO color proofer and an Optronics
color film writer.
Structure of GIS data
The data for the GIS are collected from the different
working groups of the Research Project and additional
topographic information. For that purpose a data catalog
a data catalog which contains data as "raw" files exists.
The data structure is designed according to the main
disciplines. Due to the ARC/INFO concept the data are
organized in a layer structure.
1. Main directory - ANDES
This directory contains a README, the macros and
menus.
The README holds a short description of the structure
and contents of the GIS including information about each
data coverage, grid or tin and its attribute data.
The macros and menus were developed for the usage of
the GIS by different users without special GIS knowledge.
359
The main functions are to bring up an overview menu for
searching and overlaying of data in any order or scale. In
this menu the user cannot edit, damage or corrupt the
data.
For editing, digitizing and converting of data the users get
their own workspace and they manipulate their data with
the help of the appropriate menus. As background
information for editing or digitizing all satellite images
within the GIS can be used. This is very helpful for the
input of the results of geological field work.
2. Working directories
This level is divided into 6 main themes and contains the
following data:
e TOPO: general topographic information, like borders
of countries, coast lines, cities, locations of volcanoes,
salares etc.;
« GEOLOGY: geological data, like the results of field
work, a digital geological map of the Central Andes
(scale 1:1.000.000) and different local geological
maps;
e GEOPHYSICS: geophysical data, like locations of
measurement stations, results of seismic,
magnetotelluric or gravimetric measurements by the
project groups;
« DEM: elevations models from different sources and
with varying resolutions, like grids derived from
digitized maps, DEMs derived. from remote sensing
stereo data and public domain elevation data;
e IMAGES: geocoded satellite data which are kept
permanently on hard disk and their description.
The working directories also contain specially generated
look-up tables, color and symbol sets and legend keys,
which are designed for the the overlaying and mapping
functions used in the overview menu. For example, a
special kind of mapping had to developed for the results
of the magnetotelluric measurements. The induction
arrows that provide the information on the conductivity
Situation have to be rotated and shifted in the rotation
direction.
For data management, like transformation, integration,
organization of attributes, and error handling, the GIS
Specialists obtain the necessary information for their task
from the working groups. The development of special
data analysis methods requires close cooperation
between the GIS specialists and the different scientists.
INTEGRATION OF REMOTE SENSING DATA
Landsat TM as a basic information level
Remote sensing data provide the basic information level
in the Andean GIS. More than 30 Landsat TM scenes
were processed. The georeferencing of the TM scenes
was accomplished by utilizing available maps of different
types and at scales varying from 1:500,000 to 1:50,000.
In addition, GPS measurements in the field were carried
out for additional geometric control.
A georeferenced digital color mosaic of the entire study
area was created from the TM scenes (bands 7, 4 ,1 in
RGB) with a spatial resolution of 50 m based on maps at
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B4. Vienna 1996
