[求助]如何实现由线生成面？？

我想请教大伙一个问题，当我用一条线将一个多边形切割后（比如被分成两分），那么我如何只让它显示一个被切割后的多边形？

你可以看看本版面的那个多边形切割的贴

让斑竹见笑了，那个贴子我是看过的。我的意思是说，我先是用线画（比如在矩形区域画），那么它在边界处要与之相闭合，这时我能不能将由线和边界所组成的闭合区域存储为一个Shape文件呢？

我理解你的意思还是：用线分割一个面，那个分割程序基本能实现，，关于你说的存储为另一个shape文件，能啊，定义一个数据集来保存你的对象，保存为一个shp文件就行。

楼上的兄弟，你所指的“对所有交叉线进行切割，生成一个完全没有交叉的线段集
”是怎么回事呀？那该怎么处理那个交叉点呢？
兄弟懂得不是很多，请见谅！

kentcoon所说，个人感觉过于复杂，在mo中不必那么复杂吧？wavvylia用你说的意思是否类似多边形切割？用一个多边形去剪裁一个图层？

也不尽然，我是用等值线生成等值面的，线我倒是能画出来，可下面我就不知道该怎么做了，有个朋友倒是给我提供了一个算法，但是用PB写的，看了几遍，没看懂，不知那个兄弟给帮忙看一下？

附上代码：（注：此代码源自一个姓李的网友。）

1.初始化：
oleobject lycur
oleobject bandrec,bandline,contourrec

dcshp = Create OleObject
lycur = Create oleobject

dcshp.ConnectTONewObject("MapObjects2.DataConnection")

shppath = "D:\my work\polyline2polygon\air"
dcshp.Database = shppath
If not dcshp.Connect then
MessageBox ("错误信息","图形数据库连接失败,请检查")
return
end if

lycur.connecttonewobject("mapobjects2.maplayer")
lycur.GeoDataset = dcshp.FindGeoDataset("band")
ole_map.Object.Layers.Add(lycur)
bandrec = lycur.records
bandline = bandrec.fields.item("shape").value

lycur.connecttonewobject("mapobjects2.maplayer")
lycur.GeoDataset = dcshp.FindGeoDataset("air_point")
ole_map.Object.Layers.Add(lycur)

contourrec = lycur.records
string  theid, therq

therq = "990101"
double thevalue
do until(contourrec.eof)
jcpoint[UpperBound(jcpoint) + 1] = contourrec.fields.item("shape").value.x
jcpoint[UpperBound(jcpoint) + 1] = contourrec.fields.item("shape").value.y
theid = contourrec.fields.item("id").value
SELECT jc.tsp  
     INTO :thevalue  
     FROM jc  
   WHERE ( jc.p_code = :theid ) AND  
         ( jc.str_date = :therq )   ;
// messagebox("",string(thevalue))
jcpoint[UpperBound(jcpoint) + 1] = thevalue
jccount ++
contourrec.movenext()
loop
bandpoint[1] = bandline.extent.left
bandpoint[2] = bandline.extent.bottom
bandpoint[3] = bandline.extent.right
bandpoint[4] = bandline.extent.top


2.生成等值线：
//messagebox("",string(ole_map.object.layers.count()))
if(ole_map.object.layers.count() > 2) then
ole_map.object.layers.remove(0)
end if

string  outputfname = "contours"
string file_name
file_name= shppath + "\" + outputfname
double thewgjl,thexs

contourstep = 0.01
issqrt = -2
thewgjl = 4000
thexs = 0.5

string strref
strref = string(bandpoint[1]) + "," + string(bandpoint[2]) + "," + string(bandpoint[3]) + "," + string(bandpoint[4]) + ","
strref = strref + string(issqrt) + "," + string(thewgjl) + "," + string(contourstep) + "," + string(thexs) + "," + file_name + "," + string(jccount)
int i
for i = 1 to upperbound(jcpoint)
strref = strref + "," + string(jcpoint)
next
strref = strref + ","
//messagebox("",strref)
GetContours(strref) //调用计算等值线的dll


oleobject lycur
lycur = create oleobject
lycur.connecttonewobject("mapobjects2.maplayer")
lycur.GeoDataset = dcshp.FindGeoDataset(outputfname)
ole_map.Object.Layers.Add(lycur)
ole_map.object.refresh()


3.等值线2范围面的函数：
contourstep = contourstep * 1000

oleobject lycur

lycur = Create oleobject

oleObject bandrec,contourrec,beforerec,thisrec
oleObject bandline,contourline,theline,contourpolygon,closepolygon[]
double contourvalue,closevalue[]
integer pointcount
contourpolygon = create oleobject
contourpolygon.connecttonewobject("mapobjects2.polygon")

bandrec = ole_map.object.layers.item("band").records
bandline = bandrec.fields.item("shape").value

contourrec = ole_map.object.layers.item("contours").records

lycur.connecttonewobject("mapobjects2.maplayer")
lycur.GeoDataset = dcshp.FindGeoDataset("contours_polygon")
//ole_map.Object.Layers.Add(lycur)
oleobject pgrec
pgrec = lycur.records

if(not pgrec.eof) then
pgrec.edit()
do until(pgrec.eof)
pgrec.delete()
pgrec.movenext()
loop
end if
//先将开曲线端点围绕边界按逆时针排列

oleobject thepoint[],theline[]
double thevalue[]
integer thetimes[],thebian[],anotherindex[],j,i = 1
contourrec.movefirst()
do until(contourrec.eof)
contourline = contourrec.fields.item("shape").value
contourvalue = contourrec.fields.item("valu").value
pointcount = contourline.parts.item(0).count()
if(contourline.parts.item(0).item(0).x = contourline.parts.item(0).item(pointcount - 1).x and &
      contourline.parts.item(0).item(0).y = contourline.parts.item(0).item(pointcount - 1).y) then //如果封闭
contourpolygon.connecttonewobject("mapobjects2.polygon")
contourpolygon.parts.add(contourline.parts.item(0))
pgrec.addnew()
pgrec.fields.item("shape").value = contourpolygon
pgrec.fields.item("value").value = contourvalue
pgrec.fields.item("flag").value = 1
pgrec.update()
closepolygon[UpperBound(closepolygon) + 1] = contourpolygon
closevalue[UpperBound(closevalue) + 1] = contourvalue
contourrec.movenext()
continue
end if
thepoint = contourline.parts.item(0).item(0)
theline = contourline
thevalue = contourvalue
anotherindex = i + 1

thepoint[i + 1] = contourline.parts.item(0).item(pointcount - 1)
theline[i + 1] = contourline
thevalue[i + 1] = contourvalue
anotherindex[i + 1] = i

i = i + 2
contourrec.movenext()
loop
for i = 1 to UpperBound(thepoint)
thetimes = 0
if(abs(thepoint.y - bandline.extent.bottom)<1) then
thebian = 10
elseif(abs(thepoint.x - bandline.extent.right)<1) then
thebian = 20
elseif(abs(thepoint.y - bandline.extent.top)<1) then
thebian = 30
elseif(abs(thepoint.x - bandline.extent.left)<1) then
thebian = 40
end if
next
//messagebox("ok","ok1")

oleobject pband1,pband2,pband3,pband4
pband1 =create oleobject
pband2 =create oleobject
pband3 =create oleobject
pband4 =create oleobject

i = UpperBound(thepoint)

i++
pband1.connecttonewobject("mapobjects2.point")
pband1.x = bandline.extent.left
pband1.y = bandline.extent.bottom
thepoint = pband1
theline = bandline
thevalue = 0
anotherindex = 0
thebian = 5
thetimes = 1

i++
pband2.connecttonewobject("mapobjects2.point")
pband2.x = bandline.extent.right
pband2.y = bandline.extent.bottom
thepoint = pband2
theline = bandline
thevalue = 0
anotherindex = 0
thebian = 15
thetimes = 1

i++
pband3.connecttonewobject("mapobjects2.point")
pband3.x = bandline.extent.right
pband3.y = bandline.extent.top
thepoint = pband3
theline = bandline
thevalue = 0
anotherindex = 0
thebian = 25
thetimes = 1

i++
pband4.connecttonewobject("mapobjects2.point")
pband4.x = bandline.extent.left
pband4.y = bandline.extent.top
thepoint = pband4
theline = bandline
thevalue = 0
anotherindex = 0
thebian = 35
thetimes = 1
//messagebox("ok","ok2")
oleobject templine,temppoint
integer tempbian,tempanotherindex,temptimes
double  tempvalue
boolean change = false

for i = 1 to UpperBound(thepoint)
for j = i + 1 to UpperBound(thepoint)
if(thebian[j] > thebian) then
change = false
elseif(thebian[j] < thebian) then
change = true
elseif(thebian = 10 and thepoint[j].x < thepoint.x) then
change = true
elseif(thebian = 20 and thepoint[j].y < thepoint.y) then
change = true
elseif(thebian = 30 and thepoint[j].x > thepoint.x) then
change = true
elseif(thebian = 40 and thepoint[j].y > thepoint.y) then
change = true
else
change = false
end if

if(change) then
temppoint = thepoint
templine = theline
tempbian = thebian
tempanotherindex = anotherindex
tempvalue = thevalue
temptimes = thetimes

thepoint = thepoint[j]
thepoint[j] = temppoint
thebian = thebian[j]
thebian[j] = tempbian

if(anotherindex <> j) then
theline = theline[j]
thetimes = thetimes[j]
anotherindex = anotherindex[j]
thevalue = thevalue[j]
if(anotherindex > 0) then anotherindex[anotherindex] = i

theline[j] = templine
thetimes[j] = temptimes
anotherindex[j] = tempanotherindex
thevalue[j] = tempvalue
if(anotherindex[j] > 0) then anotherindex[anotherindex[j]] = j
end if
end if
next
next

integer index
oleobject mypoints
mypoints = create oleobject
mypoints.connecttonewobject("mapobjects2.points")
//messagebox("ok","ok3")
double minvalue,maxvalue
integer inum
for i = 1 to UpperBound(thepoint)
if(thetimes > 1) then continue
minvalue=1000000
maxvalue=-1000000
index = i
mypoints.connecttonewobject("mapobjects2.points")
mypoints.add(thepoint[index])
thetimes[index] = thetimes[index] + 1
do while(true)
if(index = UpperBound(thepoint)) then
index = 1
else
index++
end if
if(index = i) then exit
mypoints.add(thepoint[index])
thetimes[index] = thetimes[index] + 1
if(anotherindex[index] = 0) then continue
pointcount = theline[index].parts.item[0].count()
if(theline[index].parts.item[0].item[0].x = thepoint[index].x and &
                             theline[index].parts.item[0].item[0].y = thepoint[index].y) then
for inum = 0 to (pointcount - 1) step 1
mypoints.add(theline[index].parts.item[0].item[inum])
next
else
for inum = (pointcount - 1) to 0 step -1
mypoints.add(theline[index].parts.item[0].item[inum])
next
end if
if(thevalue[index] < minvalue) then minvalue = thevalue[index]
if(thevalue[index] > maxvalue) then maxvalue = thevalue[index]

index = anotherindex[index]
if(index = i) then exit
thetimes[index] = thetimes[index] + 1
loop
contourpolygon.connecttonewobject("mapobjects2.polygon")
contourpolygon.parts.add(mypoints)
pgrec.addnew()
pgrec.fields.item("shape").value = contourpolygon
pgrec.fields.item("value").value = minvalue
if(minvalue = maxvalue) then
pgrec.fields.item("flag").value = 1               //表示还需处理的
else
pgrec.fields.item("flag").value = 0
end if
pgrec.update()
closepolygon[UpperBound(closepolygon) + 1] = contourpolygon
// closevalue[UpperBound(closevalue) + 1] = contourvalue
next
pgrec.stopediting()


oleobject lyjg
lyjg = create oleobject
lyjg.connecttonewobject("mapobjects2.maplayer")
lyjg.GeoDataset = dcshp.FindGeoDataset("contours_jg")
ole_map.Object.Layers.Add(lyjg)
oleobject jgrec,befrec,aftrec
jgrec = lyjg.records

integer theflag

if(not jgrec.eof) then
jgrec.edit()
do until(jgrec.eof)
jgrec.delete()
jgrec.movenext()
loop
end if
oleobject initpolygon
oleobject cutpolygon
oleobject jgpolygon
//double themin = 1000000
//pgrec.movefirst()
//do until(pgrec.eof)
// if(themin > pgrec.fields.item("value").value) then
// themin =  pgrec.fields.item("value").value
//pgrec.movenext
//loop
oleobject mypolygon[]
integer myflag[]
double mycontour[]

pgrec.movefirst()
do until(pgrec.eof)
initpolygon = pgrec.fields.item("shape").value
minvalue = pgrec.fields.item("value").value

theflag = pgrec.fields.item("flag").value
// if(theflag =0) then
// jgrec.addnew()
// jgrec.fields.item("shape").value = initpolygon
// jgrec.fields.item("minvalue").value = minvalue
// jgrec.fields.item("range").value = string(minvalue) + "--"  +string(minvalue + contourstep)
// jgrec.update()
//
// pgrec.movenext()
// continue
// end if

mypolygon[UpperBound(mypolygon) + 1] = initpolygon
mycontour[UpperBound(mycontour) + 1] = minvalue
myflag[UpperBound(myflag) +  1] = theflag

pgrec.movenext()
loop
for i = 1 to UpperBound(mypolygon)
minvalue=1000000
maxvalue=-1000000
if(mycontour < minvalue) then minvalue = mycontour
if(mycontour > maxvalue) then maxvalue = mycontour
jgpolygon = mypolygon
for j = 1 to UpperBound(mypolygon)
if(i = j) then continue
if(isnull(jgpolygon)) then
messagebox("出错提示","TOPO运算有问题,可能是seft_insertect造成!")
// pg1 = mypolygon
// pg2 = mypolygon[j]
// aaa = true
// ole_map.object.trackinglayer.refresh(true)
jgpolygon = mypolygon
continue
end if

if(abs(abs(mycontour[j] - mycontour) - contourstep) > 0.0000001 and abs(mycontour[j] - mycontour) > 0.000001) then continue
if(myflag = 0 and mycontour[j] - mycontour < -0.0001) then continue //范围在minv--minv+dgj 排除minv-dgj

if(mypolygon.IsPointIn(mypolygon[j].parts.item[0].item[0]) and mypolygon.IsPointIn(mypolygon[j].Centroid)) then

jgpolygon = jgpolygon.Difference(mypolygon[j])
if(mycontour[j] < minvalue) then minvalue = mycontour[j]
if(mycontour[j] > maxvalue) then maxvalue = mycontour[j]
end if
// end if
next
jgrec.addnew()
jgrec.fields.item("shape").value = jgpolygon
jgrec.fields.item("minvalue").value = minvalue
if(minvalue = maxvalue) then
jgrec.fields.item("range").value = "done know"
else
jgrec.fields.item("range").value = string(minvalue) + "--" + string(maxvalue)
end if
jgrec.update()

next

jgrec.stopediting()

oleobject donerec,xjrec,doneshape
double donevalue,xjvalue
do while(true)
donerec = lyjg.SearchExpression("range = ~'done know~'")
if(donerec.eof) then exit
do until(donerec.eof)
donevalue = donerec.fields.item("minvalue").value
doneshape = donerec.fields.item("shape").value
xjrec = lyjg.SearchShape(doneshape,5,"")
if(xjrec.eof) then
donerec.movenext()
continue
elseif(xjrec.count() < 2) then
donerec.movenext()
continue
end if

xjvalue = xjrec.fields.item("minvalue").value
if(abs(donevalue - xjvalue) < 0.1) then  //可能是自己
xjrec.movenext()
xjvalue = xjrec.fields.item("minvalue").value
end if
// messagebox("",string(xjvalue))
// messagebox("",string(donevalue))
donerec.edit()
if(abs(donevalue - xjvalue) < 0.1) then
donerec.fields.item("minvalue").value = donevalue - contourstep
donerec.fields.item("range").value = string(donevalue - contourstep) + "--" + string(donevalue)
else
donerec.fields.item("minvalue").value = donevalue
donerec.fields.item("range").value = string(donevalue) + "--" + string(donevalue + contourstep)
end if
donerec.update()
donerec.movenext()
loop
donerec.stopediting()
loop


//oleobject strsUniqueValues
//strsUniqueValues = create oleobject
//strsUniqueValues.connecttonewobject("mapobjects2.Strings")

jgrec = lyjg.records

jgrec.MoveFirst()
Do until(jgrec.EOF)
//  strsUniqueValues.Add( jgrec.fields.item("minvalue").Value)
  strsUniqueValues[upperbound(strsUniqueValues) + 1] = jgrec.fields.item("minvalue").Value
  jgrec.MoveNext()
Loop
double doutemp
For i = 1 To upperbound(strsUniqueValues)
for j = i + 1 to upperbound(strsUniqueValues)
if(strsUniqueValues > strsUniqueValues[j]) then
doutemp = strsUniqueValues
strsUniqueValues = strsUniqueValues[j]
strsUniqueValues[j] = doutemp
end if
next
next

oleobject vren
vren = create oleobject
vren.connecttonewobject("mapobjects2.valuemaprenderer")
lyjg.Renderer = vren
lyjg.Renderer.SymbolType = 2
lyjg.Renderer.Field = "minvalue"
lyjg.Renderer.ValueCount = upperbound(strsUniqueValues)

integer green,greenstep
greenstep = 100 / upperbound(strsUniqueValues)
For i = 0 To upperbound(strsUniqueValues) - 1
green = 50 + (greenstep * i)
   lyjg.Renderer.Value = strsUniqueValues[i+1]
lyjg.Renderer.Symbol(i).Color = rgb(0,green,0)
lyjg.renderer.symbol(i).outline = false
Next

ole_map.object.refresh()

destroy lycur

有没有VB的代码呀，我看不懂！！

对啊。我也想要VB代码。这个代码看不懂