idl中的几何运算

1、IDL中的几何图形数学运算几何形状，分为点、线、多边形（面）、体几类，利用IDL对这些形状的几何运算，大致分下面几个部分。1、点集运算点与点之间求距离： DISTANCE_MEASUREIDL自带）2、线相关计算点到直线的距离 PNT_LINE （IDL自带）或 CalDistancePtoL计算两直线的交点 CAL2LINESINTERSECTPOINT.pro线段与坐标轴的夹角（数学坐标系）3、多边形相关（面）求多边形面积：poly_area、（IDLanROI）-> ComputeGeometry, area = result （

2、IDL 自带） 求多边形周长：（IDLanROI）-> ComputeGeometry, PERIMETER = result IDL 自带）点坐标是否在多边形范围内：（IDLanROI）->ContainsPoints （IDL自带）三点求通过该系列三个点的圆心坐标和圆半径；CIR_3PNT（IDL自带）多边形与曲面交集： MESH_CLIP（IDL自带）两个多边形合并：MESH_MERGE（IDL自带）多边形是否空间闭合：MESH_ISSOLID（ IDL自带）多边形包含的三角形个数：MESH_NUMTRIANGLES IDL自带）复杂多边形正确显示：IDLgrTessella

3、tor （IDL自带）求两个平面的夹角 四面体与平面相交：TETRA_CLIR IDL自带）4、体相关体数据任意方向切面：EXTRACT_SLICEIDL自带）重点推荐MESH_OBJ可以创建三角形、矩形、圆锥、圆柱、任意多边形旋转等。;Mesh_Obj,2, Vertex_List, Polygon_List, $;调用格式;Mesh_Obj, Type, Vertex_List, Polygon_List , $;Arrayl , Array2 , /CLOSED , /DEGREES , $;P1, P2, P3, P4, P5 = value;Typ

4、e = 6创建旋转后模型的点坐标及连接关系;Vertex_List创建后的点坐标集;Polygon_List旋转模型的点连接关系;Array1创建旋转模型的起始数据集;Array2 'Type为6'时不支持;/Closed旋转后模型闭合;/DEGREES旋转的输入参数为角度，默认是弧度;P1 旋转后的边数;P2 -旋转的中心点;P3 -旋转的方向0,0,1;P4 -旋转起始角度;P5 -旋转结束角度附源码：附源码: ; 仝叁计算两个点的距离Write By DYQ可用distance_measure函数替代 function CalDistance, pointl, point

5、2 compile_opt idl2 Return,SQRT(point10-point20)A2+(point11-point21)A2+(point12-point 22)a2) end; 仝叁 Write By ZML 计算点到直线的距离 s = SQRT(p*(p-a)*(p-b)*(p-c)p = (a+b+c)/2 Modified By DYQ function CalDistancePtoLine, point0,linePos1,linePos2a = CalDistance(point0,linePos1) b =CalDistance(point0,linePos2);S

6、QRT(point0-linePos20)A2+(point1- linePos21)A2)c =CalDistance(linePos1,linePos2);SQRT(linePos20-linePos10)A2+(line Pos21-linePos11)A2)p = (a+b+c)*0.5s = SQRT(p*(p-a)*(p-b)*(p-c)Return, s*2/c end ; ;求集合的并集 copy From DAVID's Code a aJFUNCTION SETUNION, a, b；COMPILE_OPT StrictArrIF N_ELEMENTS(a) EQ

7、0 THEN RETURN, b;A union NULL = aIF N_ELEMENTS(b) EQ 0 THEN RETURN, a;B union NULL = bRETURN,WHERE(HISTOGRAM(a,bOMin = omin) + omin ; Return combined set END ； ;去除2维数组中重复的元素;2010年3月25日;Write By DYQ;FUNCTION UNIQARRAY, inArray ;num = N_ELEMENTS(inArray0,*)xArray = REFORM(inArray0,*) yArray = REFORM(i

8、nArray1,*);xUniq = UNIQ(xArray(SORT(xArray) yUniq = UNIQ(yArray(SORT(yArray) ;RETURN, inArray*,SETUNION(xUniq,yUniq)END ;计算两个点的距离，XY水平面;2008-4-28;Write By DYQ;其实可以用DISTANCE_MEASURER,没办法，写好了才发现IDL自带 o( n_n )o;FUNCTION CALDISTANCE, pointl, point2pointl = point1*1.point2 = point2*1.RETURN, SQRT(point10

9、-point20)A2+(point11-point21)A2) END ;计算点到直线的距离Write By DYQ其实可以用PNT_LINE函数，没办法，写好了才发现IDL自带o(A_n)o FUNCTION CALDISTANCEPTOLINE, point0,linePos1,linePos2a = CALDISTANCE(point0,linePos1) b =CALDISTANCE(point0,linePos2);SQRT(point0-linePos20)A2+(point1- linePos21)A2)c =CALDISTANCE(linePos1,linePos2);SQR

10、T(linePos20-linePos10)A2+(linePos21-linePos11)A2)p = (a+b+c)*0.5s = SQRT(p*(p-a)*(p-b)*(p-c)RETURN, s*2/cEND;计算两直线的交点2008-9-27Write By DYQ输入P1:直线1的起点坐标-P2:直线1的终点坐标P1S:直线2的起点坐标-P2S:直线2的终y点坐标相交则返回交点，不相交则返回-1Modified By DYQ2008-10-29 - 增加了 p1、p2及P1S P2s重合的判断Example:直线：-1,-1,1,1；直线：1,0,0,1;point = Cal2l

11、inesintersectpoint(-1,-1,1,1,1,0,0,1)FUNCTION CAL2LINESINTERSECTPOINT, P1,P2,P1S,P2s；COMPILE_OPT IDL2；如果线1点重合了IF ARRAY_EQUAL(P1, P2) THEN BEGINIF ARRAY_EQUAL(P1S, P2S ) THEN BEGINIF P1 EQ P2 THEN RETURN,P1RETURN, -1ENDIF ELSE BEGINIF CALDISTANCEPTOLINE(P1,P1S,P2S) EQ 0 THEN RETURN, P1 RETURN,-1ENDEL

12、SE；线1的点不重合ENDIF ELSE BEGINIF ARRAY_EQUAL(P1S ,P2S) THEN BEGINRETURN, P1SENDIF ELSE BEGIN;如果第一条直线垂直x轴IF (P10-P20) EQ 0 THEN BEGINipX = p10;第二条也垂直IF (P1S0-P2S0) EQ 0 THEN BEGIN;不相交RETURN, -1 ENDIF ELSE BEGIN;k2 = FLOAT(P1S1-P2S1)/(P1S0-P2S0)b2 =FLOAT(P1S0*P2s1-P2s0*P1S1)/(P1S0-P2s0) ;ipY = k2*ipX+b2RE

13、TURN,ipX,ipY ENDELSE;第二条直线垂直X轴ENDIF ELSE IF (P1S0-P2S0) EQ 0 THEN BEGINipX = p2s0;k1 = FLOAT(P11-P21)/(P10-P20)b1 = FLOAT(P10*P21-P20*P11)/(P10-P20)ipY = k1*ipX+b1RETURN,ipX,ipY;都不垂直ENDIF ELSE BEGINk1 = FLOAT(P11-P21)/(P10-P20)bl = FLOAT(P10*P21-P20*P11)/(P10-P20) ；k2 = FLOAT(P1S1-P2S1)/(P1S0-P2S0)b

14、2 = FLOAT(P1S0*P2s1-P2s0*P1S1)/(P1S0-P2s0)；如果都垂直Y轴IF (K2 EQ 0) AND(K1 EQ 0) THEN RETURN,-1ipX = (b2-b1)/(k1-k2)ipY = (k1*b2-k2*b1)/(k1-k2)RETURN,ipX,ipYENDELSEENDELSEENDELSE；END；;计算平面上直线是否与多边形相交，有交点可返回;2010年3月25日;Write By DYQ ;调用格式 result = CalLineInPolygon(linePoints, polyPoints);LinePoints:两个点的二维坐

15、标2,2,否则返回-1;PolyPoints:多边形点的二维坐标2,n,否则返回-1;FUNCTION CALLINEINPOLYGON, linePoints, polyPoints COMPILE_OPT idl2 ;IF ARRAY_EQUAL(SIZE(inPoints,/dimension), 2,2) THEN RETURN,-1 ;点个数pointNum = (SIZE(polyPoints,/dimension)1;相交标识 sign = -1 ipoints = 0,0 ;循环求解 FOR i=0, pointNum -1 DO BEGIN ;point = CAL2LINE

16、SINTERSECTPOINT(linePoints*,0, $ linePoints*,1, polyPoints*,i,polyPoints*,(i+1) MODpointNum)IF N_ELEMENTS(point) GT 1 THEN BEGIN ipoints = iPoints,REFORM(point) sign = 1ENDIFENDFOR；IF sign EQ -1 THEN RETURN, sign $ELSE result = UNIQARRAY(iPoints*,1:N_ELEMENTS(iPoints0,*)-1) ；判断交点是否在多边形内；oROI = OBJ_N

17、EW('IDLanROI', polyPoints)conArr = 0,0FOR i=0, N_ELEMENTS(result)/2-1 DO BEGIN ；psign= oROI->CONTAINSPOINTS(result*,i);有在多边形内的点IF psign NE 0 THEN BEGIN conArr = conArr, result*,iENDIFENDFOROBJ_DESTROY,oROI；IF N_ELEMENTS(conArr)/2 EQ 1 THEN RETURN, -1 ELSERETURN,conArr*,1:N_ELEMENTS(conArr

18、)/2-1ENDJ J;根据经过两点线段与坐标轴的夹角(弧度) ;Point1 到 point2 线段;Write By DYQ;2007-10-27;FUNCTION Cal2pointsangle ,point1,point2 ;point1 = FLOAT(point1)point2 = FLOAT(point2) ;dx = point20- point10dy = point21- point11IF dx EQ 0 THEN BEGIN ; x 轴IF dy GT 0 THEN result = !PI/2 ELSE $ result = 3*!PI/2ENDIF ELSE BEGINIF dy EQ 0 THEN BEGIN ;x 轴I