natical 
lation- 
dling’, MAP REVISION USING DIGITAL ORTHOPHOTOS 
d Con: C. Armenakis and A. M. Regan 
TEMS 
Canada Centre for Topographic Information / Centre canadien d'information topographique 
IS. and Geomatics Canada / Géomatique Canada 
Vill be 615 Booth St. / 615 rue Booth, Ottawa, Ontario, K1A OE9 
tel.: (613) 992-4487, fax.: (613) 947-7948 
"Arten: e-mail: costas.armenakis/anna.regan @ geocan.nrcan.gc.ca 
1s der 
Jniver- ISPRS Commission IV, WG IV/3 
| Scale 
\nnual KEY WORDS: Map revision, Orthoimages, Change detection 
Müßig 
nages, ABSTRACT 
Digi- 
[SPRS As a number of topographic organizations is in the process of completing their spatial databases, most of their 
6. current efforts are directed towards maintaining their databases and maps up to date through an extensive 
ng an revision program. This paper presents the results of the development and implementation of a concept for map 
32. if revision of the 1:50 000 National Topographic Series maps using digital orthophotos, and refers to some 
= potential methodologies to support change detection from multi-temporal orthoimages. 
1: Au- 1. INTRODUCTION 
e Ap- between the two data sets, one has to compare the 
Ly, ed- The National Topographic Series (NTS) of maps contents of the two different databases. The use of 
serve as the fundamental framework for a number homogeneous data from both sources will facilitate | 
carto- of applications from resource development, the comparison operations. This homogeneity | 
- Car- environmental protection and conservation to refers to similar-type of data reduced to a | 
2. transportation, communications, search and common reference. One way to perform this | 
rating rescue operations and sovereignty. Maps have comparison is by viewing both data sets | 
y, in been produced using conventional and digital simultaneously. This is accomplished with the | 
Car- methods and most of the current efforts are superimposition of the existing "old" digital vector | 
1721. directed at maintaining the existing databases and data over digital "new" aerial orthophotography. 
tional maps up to date through an extensive revision The digital orthophotos provide for an accurate 
program. There is a constant effort to improve the orthographic reference (geometrically equivalent 
senta- process and minimized the time to update the to a line map) for the images of the features. The 
topographic database and to produce maps which integration of vector and raster data allows the 
DOT: satisfy the increasing demand for current and operator to view the map vector data as an 
niken, accurate geo-related information. overlay on the image and thus, to detect visually 
orma- . patterns of non-matching elements between the 
This paper presents the results of the development two data sets. 
Fs and implementation of a concept for map revision 
g and of the 1:50 000 National Topographic Series maps The updating operations of existing "old" vector 
using digital orthophotos, and refers to some data from "new" orthoimages require the 
X finie potential methodologies for automating change following steps: 
Map- detection. 
; and - change detection 
.2. METHODOLOGY - photo-interpretation (feature classification) 
liques - collection of new data (feature extraction) 
ls, in Usually, a topographic database represents the - integration of old and new data for populating 
Sym- "previous/old" state of the geographical domain, the database 
tion’, while recent air photography represents the - map production. 
sland, “current/new” state. To identify the differences 
95 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B4. Vienna 1996