The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B4. Beijing 2008 
able of be download from the server. It is not necessary to 
stored raw data and final results, so the requirement of 
workstation is lower than the traditional DPW and is helpful to 
reduce the produce cost. 
3. WORKFLOWS 
Seamless mapping system is a combination of CS mode and 
P2P mode, features and advantages of server and workstation 
are discussed above. The whole workflows of seamless 
mapping system are introduced in the following. Whole 
workflows are illustrated as the figure 7. 
Figure 7. Workflows of seamless mapping system 
The whole workflows begin with the data preparing at the 
server end. In the step, all raw data and metadata must be 
collected and deposited at the server end. All necessary data are 
collected and the next step is to create a project at the server 
end. A project is the process unit of the remained steps in the 
whole workflows. A new block and strips are set up in this step. 
In order to automatic process of data, pre-processing is 
necessary. Pre-processing includes format conversion and 
geometric and radiated processing of images. Data importing is 
also necessary in practice to reuse the data produced in other 
systems. Automatic process includes automatic tie point 
measurement, automatic aerial triangulation, and automatic 
DSM matching and DOM generation. Parallel and distributed 
computation technologies are applied to improve the data 
process efficiency of the whole system. In the hardware respect, 
blade cluster or multiple PC cluster are able to be used in the 
step. Because cartographic map are unable to automatically 
processed by computers at present. Mapping must be dispensed 
to operators and be done by operators by the means of human- 
interactive measuring from stereoscopic stereo image pair. In 
the task planning step, administrator determinates how mapping 
tasks will be split and dispensed. According the number of 
available operators, mapping of a project are be split into many 
smaller mapping tasks and these smaller tasks are dispensed to 
different operators by administrators. 
After mapping tasks are dispensed, operators log in and obtain 
data related to their tasks on their workstations. There is no 
requirement of much specialization knowledge for operators in 
seamless mapping system. For operators, all that for them is just 
stereoscopically measure cartographic map on stereo image 
pairs. During their mapping, online or offline cartographic map 
mosaics are activated automatically by their systems. This step 
involves communications and data exchanges of workstation- 
server and workstation-workstation. When cartographic maps 
are measured over, operators can submit their products to the 
corresponding mapping servers. The mapping tasks of operators 
are just finished half. At the server end, these submitted 
cartographic maps will be dispensed automatically to quality 
checkers according to information of the tasks planning and 
dispensing. The checkers at the workstation end log and obtain 
these cartographic maps and related stereo models from the 
server and estimate these maps. And finally they submit their 
estimation of maps to the server. Operators should modify their 
maps according the estimation made by checkers and then 
submit the products which meet requirement of quality. At this 
stage, it is can be said that for operators the mapping tasks are 
accomplished. 
Once all smaller mapping tasks are accomplished, these 
cartographic maps are stored into cartographic map databases or 
be dispensed and be made use of immediately by other 
departments. 
4. CONCLUSIONS 
Seamless mapping system is a distributed and collaborated 
mapping system. Automatic processes and manual processes are 
separated in mapping workflows. The separation improves the 
computer’s automatic process efficiency. The task dispensing 
and task data obtaining are automatic done, there is no needs for 
operators to know what tasks they are dispensed and from 
where they obtain the related data. So it is easy to use the 
seamless mapping system for operators. Through the 
communications and interoperation among servers and 
workstations the workflows of mapping is more smooth, 
especially automatic map mosaic is helpful for collaborations of 
operators in practice and also improves the efficiency of 
manual collection of cartographic map. In the case of collecting 
map from digital aerial images, seamless switch of different 
stereo model in practice reduces a lot of workloads which must 
be done in the traditional digital photogrammetry workstation. 
The seamless mapping system is being applied to practices and 
is regarded with respect from customers. The figure 8 is a scene 
that operators are collecting cartographic map in seamless 
mapping. The results of practices indicate that the efficiency of 
collecting cartographic map in seamless mapping system 
improves by 10 percents than in the traditional DPW.