Journal of Geographic Information System, 2010, 2, 49-53
doi:10.4236/jgis.2010.21010 Published Online January 2010 (http://www.scirp.org/journal/jgis)
The Design and Realization on Effectively Fire
Tower Planning Based on MapGIS-TDE
Wenyou FAN, Xin MENG, Xiaojing LIU, Niaoniao HU
1Faculty of Information Engineering, China University of Geosciences, Wuhan, China
2Research Center for GIS software and Application Engineering, Ministry of Education
Abstract: Fire-tower is effectively applied in forest fire prevention and commanding system, especially in
fire monitor and position. After explaining the significance of scientific planning of fire-tower, this paper
analyzes GIS`s functions in building forest fire prevention system. This paper uses case study method, which
designs a model, fire tower planning and analysis, based on MapGIS platfor m. After that, it directs us how to
realize these functions based on MapGIS-TDE which is a 3D platform belonged to MapGIS. This paper gives
us scientific ways to fire tower planning in forest fire system which promotes informationization of forest fire
prevention management.
Keywords: MapGIS-TD E, f orest fire p reve ntion , 3D , f ire tower planning, vis ual analy s is
1. Introduction
Forest fire prevention has already become a global ques-
tion. Countries around the world put plenty of money in
researching forest fire prevention technology to reduce
loss in fire accident. Fire tower, cruise aircraft and satel-
lite monitoring are three ways to monitor forest fire, but
fire tower is the major tool for forest fire prevention in
china so far.
Fire tower `s primary target is to find and report fire in
time. To avoid blind spots in monitoring and provide
more accurate fire information in limited time, scientific
planning fire tower become very important. On the other
hand, it will save a great deal of money if we can scien-
tifically plan fire tower and maximize the actual per-
formance of fire tower.
2. System Introduction
Location principle is primary for fire tower planning and
analysis. Under the designed principle and powerful GIS
spatial analysis capabilities, the fire tower can realize
visual analysis functions, which will be explained in
three layers specifically.
One is support layer which includes entire operational
environment and core technologies. Fire tower`s visual
analysis function mainly based on 3D information which
is different from many others functions in forest fire
prevention system. Fire tower visual analysis will lose
effectiveness even without 3D information. We can con-
clude that 3D visual technology is the key.
The second layer is logic layer. When we build an ap-
plication system, we have to make sure that technology
is appropriate to actual work flow.
The third layer is interaction layer which is used by
customers. When we designed this layer, we need to
consider customer`s habits.
3. System Design
3.1. General Program
By fully considering these three layers, this paper pro-
posed the overall design program, including data, model,
and function shown as in Figure1,
Figure 1. General structure

W. Y. FAN ET AL.
50
Fire tower planning required at least two type data:
first is digital elevation model (DEM) in planning area;
the second type is specialized drawing and 3D model of
fire tower.
Planning analysis model defined as an algorithm is to
realize planning analysis function. We must consider two
professional concepts based on purely geographic and
spatial analysis: one concept is effective planning scope.
We need to define analysis area, for a municipal forest
fire prevention system are based on the city`s terrain map.
Second is effective resolution range. The pyrotechnic
devices which installed in fire tower such as (camera and
supporting software) just like human eyes, which only
can view a limited distance. Fire town can not monitor
things beyond the distance which is the inevitable factor.
System functions design is based on data and model,
combining with actual work flow.
3.2. Design Application Functions
There are two core parts in fire tower planning analysis:
one is analysis, which calculated and showed varies of
visible and invisible result and also the visible scope. The
other is access which is to give quantitative suggestions
for multi-location selection and layout program.
Based on the cores, we can realize system functions
from four following aspects:
1) A nal y si s of singl e vi si ble p oi nt
Single-point analysis is based on single observation
tower, which research visible situation of any point wi-
thin effective planning area. There are two results from
that analysis: visible or invisible. Fire tower and target
point will be connected and the results will be displayed
in connected lines.
2) Simplify analysis of visible area
Visible area analysis also uses single fire tower as ana-
lyzing objective researching coverage of single fire tower
within the effective scope. The analyzing results which
included visible and invisible areas are distinguished by
different colors, so we can compare with scopes of two
kinds of areas very intuitively and qualitatively.
3) Optimizing analysis of visible area
It introduces fire tower resolution range factor from
“Simplify analysis of visible area”. All the area beyond
the scope will be invisible and th e result will be closer to
the fact.
4) Layout program statistic and assessment
It analyzes multi fire tower. In addition to consider
single fire tower, it also considers the overlapped area of
the visible area, and finally quantitatively evaluates the
solutions.
4. Realization of Major Functions
According to scheme of fire tower planning and analysis,
the system adopts MapGIS K9 as basic platform and
MapGISK9-TDE as 3D platform which mainly uses C/S
model. The following are simple function realization
ideas.
4.1. Single Point visual Analysis
It has two steps:
1) get distinguishable distance of fire tower
In order to enhance system`s portability ability, system
will take distinguishable distance as fire tower attribute.
We can automatically obtain its attribute information
when we choose analyzed objective.
Because fire tower is stored in 3D model, and its at-
tribute query interface is slightly different with the gen-
eral3D elements:
long flg = Get3DFeatuLayer(m_pGdataBase, "fire tower",
Temp3DLayerInfo){}
This interface includes three parameters: m_pGdata-
Base represents the geodatabase pointer in current opera-
tion; the “fire tower” string constants are the names of
the 3D layers defined by database; Temp3DLayerInfo the
3D element layer information input after pointer visiting
designed layer, which includes distinguishable distance
information.
2) judge fire tower visibility
From the technology point of view, fire tower visibil-
ity can be abstracted as inter-perspective analyses of two
points. The call interface can be defined as,
Vis iable Be-
tweenTwoDot(start3Dot,end3Dot,visiableDist)
{
//get the straight-line distance, if it beyond the
distinguishable distance, then “invisible”
long distance = GetDistanceBe-
tweenTwoDot(tart3Dot,end3Dot);
if(distance > visiableDist ){
return false;
}
//inter-perspective analyses of two points
bool flg = VisiableAnalyByT-
woDot(start3Dot,end3Dot);
}
The effective picture of single point visible analysis is
shown in Figure 2:
Figure 2. Single point visible analysis effective p icture

W. Y. FAN ET AL.
51
4.2. Simplify Analysis of Visual Area
Simplify analysis of visual area has three steps,
1) get effective analyzed scope
There are several methods for effective analyzed scope
setting. Subjectively, manually set forest geological
scope; objectively, take the pre-selected location as circle
and observations distance as radius, since this method is
interfered by lots of factors, which will not be the key
point of this paper.
Obtain a valid analytical range is to read the predeter-
mined range results, and pass to the following up process
module. The interface is as follows:
Polygon polygon = GetAnalyRange1(RegDo tArr){}
The interface only has one parameter that is the boun-
dary string coordinates in effective range. After setting
the scope, the boundary string coordinates can be stored
in any visiting database table by string splicing or point
by point record method. RegDotArr is defined as 3D
coordinates object C3DotArr in MAPGIS-TDE. After
convert the string coordinates to interfaces by definition,
we can return to polygon region object which consistent
with the effective analyzing scope.
2) fire tower visible area analysis
In fire tower visible area analysis, the effective scope
analysis obtained in the previous step will be transferred
to the following interface,
bool flg = VisibleAnalysysByPolygon(m_pGdataBase,3d
Dot, polygon, visiableId,invisiableId)
m_pGdataBase also represents geodatabase pointer in
current operation. 3dDot is a 3D point object, which is
used to indicate the location of fire tower. After that, the
analyzed results will be stored in geodatabase in raster
image. visiableId and invisiableId are the output image
identification.
3) Visualized visible area analyzed result
After analysis, the resu lts ne ed to be disp layed for u ser
identify. The interface is designed as follows,
bool flg = ShowVisibleAnalysysRlt(m_pGdataBase, visi-
ableId, invisiableId){}
VisiableId and InvisiableId are the analyzed resulting im-
ages stored in geographic database. This method is to add
image into 3D scene through geodatabase pointer and
image ID.
4.3. Optimize V isible Area Analysis
The realization method is quite the same with the above.
It only adds one process in effective analysis scope.
1) get effective analysis scope
Optimized analysis of the visible field needs to take
the fire tower distinguish parameter into practice, while
the camera in fire tower can adjust the horizontal and
vertical viewing angle in both directions. The system
design takes the fire tower center as circle and the dis-
tinguish distance as radius to form a circular region, that
is, the fire tower visible range. Then overlap the previous
set area. The intersection regions can be seen as the ef-
fective range of optimized visible field analysis. Shown
as follows:
Polygon polygon = GetAnalyRange2(RegDotArr,3d
Dot,visiableDist)
{
{
//calculate fire tower visible area
Circle circle = GetVisiableRange(3dDot,visiableDist)
//get planned analysis scope
Polygon polygon = GetAnalyRange1(RegDotArr)
//calculate the intersection of visible area and
planning analysis
Polygon polygon = GetCrossingRange(circle, pol-
ygon)
}
2) fire tower visible area analysis
Similar to the simplified visible area analysis of fire
tower, call visible area analysis interface gets gird image
analysis result. The difference is that, system will get
visible area in this area, not only take the left part as in-
visible area. It takes invisible area expands to “planning
analysis scope” and shaded areas are not visible. As
shown in Figure 3.
3) display the analysis results of visible area
The last step analysis result display effect is as follows.
We can see effective picture from figure 4 that the boun-
dary of red outline is circular, and the left blue area is
invisible, not only the blue in the circular are invisible.
Figure 3. determine scope of invisible area
Figure 4. Optimized visible area analysis effect picture

W. Y. FAN ET AL.
52
Figure 5. Determine effective area analysis of multi-fire
towers
4.4. Layout Program Statistical Planning Evalu-
ation
Layout program statistical planning evaluation is to
compare multi layout programs and select optimized
program as the reference for planning construction. First,
we should standardize the rules and design access. In this
system development, we use relative percentage of blind-
area, targeted-area and non-targeted area as the criterion.
Blind-area is defined as area which can not be monitored
by any fire tower. Non-targeted area is defined as area
which can be monitored by only one fire tower. Targeted
area is defined as area which can be monitored by two or
more than two fire towers. High percentage of targeted
area and low percentage of blind-area is the best plan-
ning.
To achieve this function, the system has the following
four -st ep processin g:
1) get effective analysis scope
Effective scope analysis for several fire towers can be
viewed as a collection after superposition of several reg-
ions, which shown as the shaded area in figure 5:
2) multi-fire tower visible area analysis
After determining the standard, we can refer the single
fire tower visible area analysis method to get related vis-
ible and invisible area.
bool flg = VisibleAnalysysByPolygon(m_pGdataBase,
3dDotArr, polygon, visiableId,i nvi si ableId)
In the above-mentioned interface, 3dDotArr represents
all the location of fire tower in layout progra m. Visiable-
Id and invisiableId respectively, are the visible and in-
visible analyzed results image identification. From the
above, we can see that the visible included single-visible
fire tower and several-visible fire tower which are dis-
tinguished by stored colors.
3) statistical area of the three regions
In the layout program statistical evaluation, one of the
most distinctive features is the quantitative evaluation,
not only the direct display of visible condition.
The so-called quantitative evaluation is to determine
the area of the targeted-area, non-targeted area and blind
area. Since analyzed results are stored in raster format,
thus the statistic will take full advantage of raster image
grid characteristics, and determine the overall percen tage
of the three regions by “grid numbers”.
4) display coverage and statistical results of three re-
gions
System will load the images which get from the last
step into the 3D scene, to get the figure 6 as effect pic-
ture. At the same time, the system will display the per-
centage of targeted-area, non-targeted area and blind area
in pie charts.
5. Conclusion
As the development of forestry information, GIS and 3D
visualization have been the main technology applied in
building forestry system. This paper designed and real-
ized the fire tower planning analysis sub-system. This
Figure 6. Layout program statistical evaluation effect picture

W. Y. FAN ET AL.
53
system uses GIS and 3D viewable analysis technologies
as key technologies. It uses MapGIS platform and 3D
platform as developed environment and shows how to
realize the fire tower planning analysis sub-system. This
system not only benefited forest management depart-
ments, for they can scientific planning fire towers, but
assistant setting new fire towers location planning, which
helps to cut the operational cost and improve forestry
management.
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