of multiple data layers varying in their structure, level of
accuracy and spatial consistency. The framework may be
composed by communication system, building areas,
land-use, administration borders and hydrography. For
the needs of Cracow project those layers were extracted
from existing topographic maps (1:25000 and 1:50000)
which are most common data source of vector data for
GIS. Features of interest were extracted using digitizer
tablets. For modernisation of these data up-to-date
Landsat TM imagery and 1:10000 maps was used.
Terrain relief is presented by digital terrain model (DTM).
Digital raster structure is used for DTM Storage.
Compilation of this structure was performed by software
for creation of DTM using cartographic data. Topographic
maps at 1: 50 000 scale presented in so-called „65 map
projection system” were used for the digitising procedure.
In cases where too little density of contour line occurred
(at build-up areas) the greater scale maps (1 : 25 000
and 1 : 5 000) were used. (Pyka, Sitek, 1993).
The whole tested area (1600 km?) was divided into 100
parts each equal 4 x 4 km in agreement with the maps
cartographic grid. The interior of each grid cell must be
filled out in uniformly by height points with density not
lesser then 80 for flat ground and 208 for mountainous
country. Altogether 43 thousand of points were digitised
with mean density 26 points/km? (minimum density 5
points/km? and maximum density 60 points/km?).
The Summagraphic || and Drawing Board |l Calcomp
digitizers as well as DIGITIZE software supporting the
IDRISI 3.0 data format was used for compilation of 100
files. This files was transferred into ASCII files setting up
data base (dBase Ill) with array: Nr, X, Y,Z.
The interpolation of DTM Cracow region was executed by
SURFER and SCOP software packages. Finally this data
was transferred to IDRISI format.
At first the DTM was compiled with 50 m interpolated
point interval grid in both directions, but as a final was
generated model with grid - nodes equal 30 m. This kind
of digital raster structure corresponds with pixel size of
TM LANDSAT scanner and better render course of
discontinuity lines.
Thematic data is directly or indirectly connected with
terrain surface (Fig.2). To the first one belongs data from
pedology, geology, hydrogeology, hydrography, land use
and the like. The indirect thematic data is helpful to
environmental pollution analysis and refer to
meteorological, demographic, the state of populations
health and the like information.
For the project needs the thematic information was
extracted from various maps or the lists, tables and other
registers which came from the reports, analysis etc.
Paper maps were converted into digital form using the
specialised program-TOSCA that supports the IDRISI
(Version 4.0) data format.
Soil - agriculture map 1 : 100 000 consist of 19 soil types
layers and 16 classes of land use. Hydrogeologic data
has collect from 1:50 000 and 1:25 000 maps of
underground water storage reservoirs. Seventeen layers
were selected. Geologic information was extracted from 9
sheets detailed geologic maps 1:50 000 separating
lithologic and stratigraphic data. All this information
creates the spatial and attribute database.
The attribute database was completed additionally by
meteorological and demographic information. The
meteorological data was composed in 2 tables. One
presenting the description of measuring stations ang the
other (for each station) containing following information:
data of measurements direction of wind power, fog
precipitation, ^ temperature, atmospheric ^ pressure
Demographic data is placed in one table showing area of
territorial division, population general, in age productive,
after productive and before productive.
Environmental pollution elements were incorporated also
into attribute database (Fig.2) but database format js
more complicated than for thematic database. The
emission of contamination is located into two kinds of
description tables. One table contains the following data:
identifier of the work place, name of the factory, address
and coordinates of emission point. The other table,
separate for each year shows emission data in the
following fields: identifier of work place, dust emission,
sulfur dioxide emission, nitrogen dioxide emission,
carbon monoxide emission, hydrocarbons emission,
other pollution emission total gases emission, production
of solid wastes, waste management, yearly waste
storage, the sum of waste accumulation.
Raster Vector map Data bases
map digitizing of sources and
scanning supported by other systems
IDRISI program
|
Conversion to
vector format
Aerial photos scan
digitization
Digital satellite
images
Parameters of
various type
computer files
v v
Basic Geographic
Database
Spatial |Attributes
Î
Gound and survey
measurements
Nan
Digital photogram
-metric input
Environmental
pollution measu-
rements and
monitoring
Contour line and
hight points
digitization
v v
Database of chosen GIS
Rasters Vectors Attributes
ANALYSIS IN GIS
Fig.2. Diagram of creation and supply the basic database
620
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B7. Vienna 1996
