mapx的Distance的奇怪问题！(100分)

Z

zangqi

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• 2003-04-15

• #1

VB中
Dim ds Asdo
uble
ds = Map1.Distance(0, 0, 180, 0)
MsgBox "距离=" + Format$(ds, "#.###") + "公里"
DS的值为12436.792
在delphi中，
edit1.Text := floattostr(map1.Distance(0,0,180,0));
值为2.63659674624068E-308
为什么在delphi中算出的值是这样的？如何解决？

 

Z

zangqi

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• 2003-04-15

• #2

up

 

Z

zangqi

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• 2003-04-15

• #3

路过的捧个人场啊！.....

 

C

chinesetree

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• 2003-04-15

• #4

var
earthCircumference:do
uble;
tempCirc: string;
begin

Map1.MapUnit := miUnitMile;
earthCircumference := 2 * Map1.Distance(0, 0, 180, 0);
tempStr := FloatToStr(earthCircumference);
Application.MessageBox(PChar('Earth''s Circumference: ' +
tempCirc + ' miles.'),'Info',0);
end;

 

C

chinesetree

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• 2003-04-15

• #5

Mapx online help

 

L

lphjj

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• 2003-04-15

• #6

up

 

Z

zangqi

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• 2003-04-15

• #7

同样的地图，同样的函数，在VB和DELPHI中算出的结果为什么不一样？（delphi的明显有误E-308）
看了mapx的帮助里面关于Distance method (Map object)的delphi的例子
var
earthCircumference:do
uble;
tempCirc: string;
begin

Map1.MapUnit := miUnitMile;
earthCircumference := 2 * Map1.Distance(0, 0, 180, 0);
tempStr := FloatToStr(earthCircumference);
Application.MessageBox(PChar('Earth''s Circumference: ' +
tempCirc + ' miles.'),'Info',0);
end;


我试了还是不行！

 

峻

峻祁连

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• 2003-04-15

• #8

---------------------------
Earth's Circumference: 24873.584977783 miles.
---------------------------

上面是我在delphi6执行mapX例子的结果，你的结果是多少？

需要注意的是mapunit，单位不同数字肯定是不同的。

 

Z

zangqi

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• 2003-04-16

• #9

Earth's Circumference: 4.82238312685783E-307 miles.
我在D6+mapx4.5的环境下得到的结果！
VB+mapx4.5就正确！
为什么，我快疯了.....

procedure TForm1.Button1Click(Sender: TObject);
var
earthCircumference:do
uble;
tempCirc: string;
begin

Map1.MapUnit := miUnitMile;
earthCircumference := 2 * Map1.Distance(0, 0, 180, 0);
tempCirc := FloatToStr(earthCircumference);
Application.MessageBox(PChar('Earth''s Circumference: ' +
tempCirc + ' miles.'),'Info',0);
edit1.Text := 'Earth''s Circumference: ' + tempCirc + ' miles.'
end;

 

Z

zangqi

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• 2003-04-16

• #10

Earth's Circumference: 4.82238312685783E-307 miles.
我在D6+mapx5.0的环境下换了一台PC得到的结果！

 

Z

zangqi

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• 2003-04-17

• #11

大侠们帮帮忙呀，我还想继续用DELPHI开发呀！

 

Z

zangqi

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• 2003-04-17

• #12

算了，我自己解决了，散分了。