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ises and 
combination of uses of the data after entry has 
taken place. It does this by maintaining data in 
form of tables which are collection of rows and 
columns. The rows are termed records or tuples 
while the columns within a row are termed the field 
of the tuple. We can combine two or more of these 
tables by grouping them based upon common referen- 
ces for the purpose of updating the database, 
[Stanlay, 1989]. 
The major controversial element in GIS is the link- 
age between geometric data and feature attribute 
data, [Herring, 1989b]. The classical approach is 
to split the two data types which usually creates 
a gap that must be hurdled every time a combined 
spatial edit or query is executed. The other extr- 
eme appraoch is to place all attribute and geomet- 
ric information in the same DBMS. This latter 
appraoch simplifies the GIS system and makes real- 
time topological maintenance. This means that 
topology is always valid and can be changed without 
reconstructing the whole topological attribute 
files. Besides, a single DBMS for attribute and 
geometric information provides a possibility of 
integrated spatial-attribute queries (Ad-hoc query) 
from the DBMS, [Herring, 1989a]. 
In this study, we have used ARC/INFO software pack- 
age which separates the topological attribute 
files (AAT & PAT INFO files) from the graphic 
files, [Morehouse, 1989]. Thus, any topological 
attributes updating can not be interpreted as 
graphic results. Also, although ARC cartographic 
package does allow some attribute manipulation, it 
is not optimized for this task. It does however 
provide very powerful graphic processing capabilit- 
ies which may be extended through its internal 
Macro language (AML or SML). Thus, if we are able 
to perform searches and updating of topological 
attributes behind a powerful graphic cartographic 
interface, we are able to assemble the major 
components of GIS using tools which are familiar 
to us and which can be turned to our particular 
requirements, [Chapman et al., 1989]. 
Various facets connected with digital data acquisi- 
tion, handling and updating are dealt with in 
several literatures, [Nassar et al., 1992].Becuase 
the scope of this paper is limited, the emphasis 
is placed on the most pertinent technical issues 
for updating the captured digital map data usinga 
proposed updating technique from the DBMS. However 
digital data acquisition, handling and the covent- 
ional techniques for updating digital map data 
will be first outlined. 
DIGITAL DATA ACQUISITION, RECOVERY 
AND CLASSIFICATION IN EGYPT 
For testing the proposed updating technique for 
large scale digital map, a map of scale 1:2500 for 
a pilot area called Beni Magdoul village has been 
chosen in Giza city in Egypt. This village has an 
area of approximately 1.5 square kilometers. The 
choice of this area in particular is due to the 
existence of a variety of features such as roads, 
buildings, cultivated lands and irrigation and 
drainage networks. The digital data acquisition, 
handling and updating processes in this study have 
been carried out using ARC/INFO software modules 
and a number of routines in a pac kage developed 
in this study in AML language and called AUDIGMAP. 
ASU, [Hassen, 1992]. The various options and their 
functions available in this package along with 
their integration with ARC/INFO commands and 
modules as achieved in this research are included 
61 
in figure (1). 
The digital data acquisition and handling process- 
es through this study can be summarized as follows: 
- Digitizing the hardcopy map for the chosen pilot 
area using a manual digitizer. 
- Building the topolgical attribute files (AAT & 
PAT INFO files) using the clean command in ARC/ 
INFO software. 
- Handling the encountered digitizing errors using 
the technique shown in figure (1) which involves a 
routine (option 2 in the developed package) to 
detect and correct the overshoot arcs and the und- 
ershoot arcs in the digitized data automatically. 
- Reconstructing the topolgical attribute files 
using the build command in ARC/INFO software. 
- Classifying map entities in terms of their land 
uses or functions automatically using option (3) 
in the developed package. Finally, the digital 
data are recovered from the cartographic and geo- 
metric errors and thus be ready to be updated, 
[Nassar et al., 1992]. 
THE PROPOSED ALTERNATIVE TECHNIQUE VESUS 
COVENTIONAL TECHNIQUES FOR UPDATING DIGITAL DATA 
Without accurate information about the lands and 
waters, and without an up-to-date information of 
country’s lands resources and their boundaries, 
the government and the people are handicapped in 
controlling their own destiny. It is not possible 
to make the best use of the land and natural 
wealth, or to prevent its mis-use, without good-up 
-date factual knowledge of the country and its 
features, [Meyor, 1991]. Digital mapping technol- 
ogy offers the promise for easier and more frequ- 
ent updating which has great potential in practice. 
With digital map technology, continuous mainten- 
ance of data files can take place. In addition, 
the map user can be provided with the most up-to- 
date data available. Thus, it seems rational to 
anticipate that there will be an increasing 
transition from the traditional technique for map 
updating to update the existing digital database, 
[Makarovic, 1982]. 
The updating of digital map has usually tradition- 
ally been performed through one of the following 
approaches, [El-Shiemy, 1990]: 
- A new photo vesus digital map file (figure 2). 
- A new large scale map vesus digital map file 
(figure 3). 
The updating scenario of digital maps within the 
above approaches is based upon updating the 
geometric attribute file (graphic file) and then 
updating the corresponding topological attribute 
records that are stored in the associated database 
files. Nowadays, tremendous improvements have been 
made within these approaches to increase the 
graphic editing capabilities. However, none of 
these approaches tried to make such updating from 
the topological attribute records using the DBMS. 
This may be due to the available traditional 
sources of updating maps such as classical survey- 
ing techniques and areal photography. 
The recent achievements in the field of database 
technology and its current powerful capabilities 
gave reason to reconsider the currently used map 
updating techniques and promote further develop- 
ment to them. This has been motivated by the 
recent sources of updating data in digital form 
such as total station surveys and remotely sensed 
imagery supplemented by the immeasurable capabil- 
ities of digital computers. Therefore, the main 
concern here is to present a non-graphic procedure