ANEW METHOD OF PHOTOGRAPHIC IDENTIFICATION IN FIELD WORK 
— EPSA PHOTOGRAPHIC IDENTIFICATION SYSTEM 
Delin Yang Professor, Tsinghua University,P.R.China 
Commission II, Working Group 1 
KEY WORDS: New Method, Photographic, Identification, Electronic Plate-table System. 
ABSTRCT 
The surveying and mapping of large scale topographic maps by aerial photogrammetric method will be more widely 
utilized in many large and medium cities in China . This paper proposes that the data acquisited by the 
stereocomparator (or analytical plotter) input into EPSA, displaying and mapping in real time. In field work, 
identified the digital map, editting and revising instantly by using EPSA on portable computer. In the office work after 
appropriate editing and modifying, it can be mapped by digital plotter which controlled by EPSA, and stored m 
mapbase or transfer into GIS. This method can raise the accuracy of photogrammetric mapping,and also improves the 
  
efficiency of works. 
EPSA is a system for data acquisting and mapping in real 
time developed by Civil Engineering Department of 
Tsinghua University and Tsinghua Sunway Technical 
Company. It can provide interface with communications 
of various Total Stations, interface with communications 
of digitizers, interface with communications of 
sterocomparators and analytical plotters. The data 
acquistion by the above instrument can be receive directly. 
In the field work, EPSA is installed on a portable 
computerthe screen is used as a plate table display 
topographic map in real time, so it is called EPSA 
(Electronic Plate-table System for Aerial 
Photogrammetric Surveying). 
EPSA is a surveying and mapping system developed in 
Windows operating system with C + + language. It is 
suitable for the surveying and mapping of large scale 
topographic maps, cadastral maps, thematic maps and 
engineering maps. The EPSA can completely replace the 
traditional surveying and mapping method. It will record 
the observed data and display the topographic map with 
the symbols of object in real time. 
1. MAIN FEATURE OF EPSA 
1.1 Surveying and Mapping in Real Time 
The surveying data can be processed in real time and the 
topographical maps can be generated in field 
automatically. The integration of the field and indoor 
operating makes it easier to find mistakes in time. 
1.2 EPSA Established a Set of Topographic Symbol 
Library with National Standards for the Scales 
1:500,1:1000,1:2000 Topographic Map and the 
Coding System. 
The symbol and coding system can be queried and 
displayed at any time during the creation of maps in the 
field. 
1.3 Powerful Graphic Editor 
EPSA adopts the object-oriented design which makes the 
editting of graphic maps simple and convenient,especially 
for site edit. 
1.4 Provide the Function of Photographic 
Indenfication 
For examples: surveying and mapping in real time; 
powerful graphic editor; correction of eaves ; lettering of 
geographical names; populated place names, oronym...; 
calibrating, surveying and mapping of ground altitude. 
408 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B2. Vienna 1996 
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