The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B3a. Beijing 2008 
we generate marker layer with subtract “a 
constant value = h” from mask layer, 
now if we do reconstruction operation 
according to marker layer ,then we will 
generate the domes network and then the peak 
points will extracted.this conception is shown in 
figure 4. 
Figure 4. Conception of surface reconstruction 
Where ; 
a) is shown mask layer ( upper layer) and marker 
layer (lower layer). 
b) is reconstructed surface as well as j-stability 
inorder to obtain demes network 
c) is domes network where; 
domes network=mask - reconstructed surface 
(j-stability) 
also there is no concern about a constant value 
selection because with increase or decrease of 
value of it, we achieve more or less peaks. 
3.2. Peaks extraction Algorithm 
The standard algorithm in order to performing 
reconstruction operation is named parallel 
reconstruction algorithm, 
this algorithm is as bellow : 
• Input: mask layer ( such as NDSM) 
• Generate the marker layer , where 
Marker layer = mask layer - a constant 
value (2) 
Reconstruction is performed directly on 
marker layer 
• Allocate work image such as k matrix on 
marker layer 
For every pixel in domain of marker 
layer: 
k(p) = max(J(p)) (3) 
J(p) is refer to community of 8 neighbors 
with the central pixel in marker layer. 
For example if we show neighbors of pixel p 
as bellow: 
1 2 3 
4 p 5 
6 7 8 
We will have: 
J(p)={l,2,3,4,p,5,6,7,8} 
• For every pixel in Domain mask layer: 
- marker layer = min(k(p) ,mask layer) (4) 
• Repeat until marker layer reach to stability 
(In fact no more pixel value in marker layer 
has been changed): 
Thus: this layer is called J stability. 
J stability = reconstructed surface (5) 
• Finally; 
Domes network = mask layer - J stability (6) 
4. Using model and results 
The parallel reconstruction algorithm is 
performance in programming language of 
Avenue in Arc view GIS software because it 
has high capabilities in working with 
network and raster data. Also the other 
capabilities of this software are easily 
extraction of coordinates and obtain height 
of peaks from NDSM. 
All of operations in order to obtain the 
network of domes is consist of two steps: 
- Implementation and performing parallel 
reconstruction algorithm 
- Extraction three dimensional coordinates 
of peaks 
4.1. Implementation and performing 
parallel reconstruction algorithm 
As we said, parallel reconstruction 
algorithm on based mathematical 
morphology was performed by help of 
Avenue programming language in Arcview 
software. 
The result of performing this algorithm lead 
to obtain reconstructed surface ( J-stability) 
and the domes network which has been 
generated with subtraction of this layer from 
mask layer (NDSM). In order to extraction 
of peak points we should extraction the 
centers of domes network as well as peak 
493