遇到奇怪问题，探讨探讨

我的想法是要把栅格文件类型中每个cell的值读出来，现在只能做出有某个值的cell有多少个（如值是５的cell有１０２２个）。但是遇到了奇怪的问题，我这段码对jpg，dem等都有效，不过遇到由ploygon转过来（用feature to raster)的栅格文件就会出现错误，此栅格文件有属性表。错误截图附上，请问是为什么？？大家讨论下！<br>

<P>Sub countnumber()</P>
<P>Dim pMap As IMap<BR>Dim pMxDocument As IMxDocument<BR>Set pMxDocument = ThisDocument<BR>Set pMap = pMxDocument.FocusMap</P>
<P>Dim pRasterlayer As IRasterLayer<BR>Set pRasterlayer = pMap.Layer(0)</P>
<P>Dim pRaster As IRaster<BR>Set pRaster = pRasterlayer.Raster</P>
<P>Dim pRasBC As IRasterBandCollection<BR>Set pRasBC = pRaster</P>
<P>Dim pRasterBand As IRasterBand<BR>Set pRasterBand = pRasBC.Item(0)</P>
<P>' This example shows the usage of the IRawPixels interface to<BR>' Read and write pixels to a raster band that is passed in.<BR>' QI for the IRawPixels interface<BR>Dim pRawPixels As IRawPixels<BR>Set pRawPixels = pRasterBand</P>
<P>' QI for the IRasterProps interface to get height and width<BR>Dim pProps As IRasterProps<BR>Set pProps = pRaster</P>
<P>Dim pPnt As IPnt<BR>Set pPnt = New DblPnt<BR>pPnt.SetCoords pProps.Width, pProps.Height</P>
<P>' Use the RawPixels interface to create a new PixelBlock<BR>Dim pPixelBlock As IPixelBlock<BR>Set pPixelBlock = pRawPixels.CreatePixelBlock(pPnt)<BR>' Create a new point to specify where to begin reading, then read<BR>' Note:the origin is specified in pixel (or image) coordinates<BR>Dim pOrigin As IPnt<BR>Set pOrigin = New DblPnt<BR>pOrigin.SetCoords 0, 0<BR>pRawPixels.Read pOrigin, pPixelBlock</P>
<P>' get the variant SafeArray from the pixelblock<BR>Dim vPixels As Variant<BR>vPixels = pPixelBlock.SafeArray(0)</P>
<P>Dim i As Long, j As Long, sum As Long, value As Double</P>
<P>value = InputBox("请输入元胞的值：", "输入框")</P>
<P>For i = 0 To pProps.Width - 1<BR>For j = 0 To pProps.Height - 1<BR> If vPixels(i, j) = value Then sum = sum + 1<BR> Next<BR>Next</P>
<P>MsgBox "此栅格图层中值为" ; value ; "的元胞有" ; sum ; "个"</P>
<P>End Sub<BR></P>

<img src="images/post/smile/dvbbs/em01.gif" /><img src="images/post/smile/dvbbs/em01.gif" />

<img src="images/post/smile/dvbbs/em08.gif" /><img src="images/post/smile/dvbbs/em03.gif" />

兄弟们有没遇到过这种问题啊？？

我发现有些有属性表的栅格文件也能用，只不过它的pixle type是unsigned integer的，这个unsigned integer是什么意思，有什么办法可以把signed integer的改成unsigned integer的