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DIGITAL PHOTOGRAMMETRIC WORKSTATION FOR TOPOGRAPHIC MAP UPDATION USING IRS-1C 
STEREO IMAGERY 
B Gopala Krishna, B Kartikeyan, KV lyer, Rebanta Mitra, PK Srivastava 
Image Processing and Data Products Group 
Remote Sensing Area 
Space Applications Centre 
Ahmedabad 380 053, INDIA 
ISPRS Commision IV, Working Group IV/3 
KEY WORDS : IRS-1C, Photogrammetric Workstation, Texture Mapping, DEM, Orthoimage, Topographic Map 
Updation 
ABSTRACT 
Panchromatic (PAN) camera onboard Indian Remote Sensing Satellite 1C (IRS-1C) acquires data in stereo mode 
with 5.8m ground resolution. It is expected that, this resolution can be comfortably used to update the topomaps 
with required accuracy for 1:50000 scale. Digital Elevation Models (DEM) can be generated from IRS-1C PAN 
stereo data with sufficient planimetric and height accuracies required for topographic mapping at that scale, 
whereas the thematic information can be derived from the merged products generated by combining IRS-1C PAN 
data with other medium resolution multispectral data sets either from IRS-1C LISS-3 (23m resolution) or from 
SPOT PLA (20m resolution). Keeping all the above points in mind, a digital photogrammetric workstation is being 
developed at Space Applications Centre (ISRO), INDIA, for topographic map updation using IRS-1C data. This 
paper describes in detail, the design concepts, various components of the system and their functionalities. Some 
early results from IRS-1C stereo data are given to show the capability of this data for topographic map updation. 
The map updation system specifications and the status of its development are given at the end. 
1. INTRODUCTION 
With the advent of IRS-1C launch during December 
1995, and its subsequent operationalisation, remote 
sensing user now has panchromatic data in high 
resolution (5.8m) in stereo mode. This is in addtion to 
the already available SPOT 10m PLA data. Earlier 
resolutions from IRS-1A, IRS-1B, LANDSAT TM, and 
SPOT, topomap updation between 1:250000 to 
1:50000 scales were possible, whereas IRS-1C 
panchromatic data resolution promises capability for 
updation of maps with scales 1:50000 and better. 
With the stereo capability of the panchromatic data 
DEMs can be generated with sufficient planimetric 
and height accuracies for topomap updation of the 
above scales. Thematic information required for 
updation can then be derived from the coarse 
resolution multispectral data either from IRS-1C LISS- 
3 or from SPOL MLA, by merging these data sets with 
the high resolution PAN. Though various systems are 
available at various centers in INDIA for Geographic 
Information System (GIS), Image Processing (IP) and 
Stereo data processing , an end-to-end topomap 
updation was not possible with any of these individual 
Systems. Also the data input/output formats are 
different at different Systems. Hence a digital 
photogrammetric workstation is conceptualised and 
being developed at this center for exclusively updating 
the topographic maps using IRS-1C stereo data. 
However plans are being made to use/extend this 
System to utilise the data from other sources i.e. data 
from different satellites having stereo imaging 
capabilities like SPOT or the future missions of IRS 
481 
and SPOT. The system includes GIS, IP and stereo 
processing functions/subsystems in an integrated 
mode. The system uses the texture mapping as the 
basic tool for integrating all the three subsystems. In 
section 2 the map updation methodology is explained 
briefly and in sections 3 and 4 fuctionalities and 
system requirements respectively are described. 
Section 5 gives some early results from IRS-1C 
stereo data. Status of system development and some 
conclusions are also given in this section at the end. 
2. MAP UPDATION METHODOLOGY 
A server client configuration is assumed (Fig. 1), 
where server does most of the database work and 
client performs the required photogrammetric 
functions and data processing. A database 
containing digital map layers are maintained at the 
server. This is used as a base information at server 
node, as an input for map updation. Additional 
information is derived from various sources of data 
from satellite/aerial images and previous maps, if any. 
Hence as and when a request comes for map 
updation, all the existing layers for that map sheet 
will be extracted and sent to the photogrammetric 
client. Additionally other inputs like stereo 
pairs/triplets, Ground Control Points (GCP) from a 
library or from a map digitizer/scanner or from an 
external DEM, are also sent to client. When no map 
layer is available for a given map sheet, it has to be 
first created by scanning the map with the relevant 
information and updating the database with this. This 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B4. Vienna 1996