Hmm. I don't follow? The revision would be this:
float GDALSlopeHydroAlg (float* afWin, float fDstNoDataValue, void* pData)
{
// Hydrologic Slope is the max
// local slope btw center cell and adjacent cells
const double radiansToDegrees = 180.0 / M_PI;
GDALSlopeAlgData* psData = (GDALSlopeAlgData*)pData;
double key;
float pafLocalMin = afWin[0];
float pafLocalMax = afWin[0];
for ( int k = 1; k < 9; k++)
{
if (afWin[k] < pafLocalMin)
{
pafLocalMin=afWin[k];
}
if (afWin[k] > pafLocalMax)
{
pafLocalMax=afWin[k];
}
}
key = afWin[4] - pafLocalMin;
if (psData->slopeFormat == 1)
return (float) (atan(sqrt(key) / (2*psData->scale)) *
radiansToDegrees);
else
return (float) (100*(sqrt(key) / (2*psData->scale)));
}
But, clearly I'm not understanding something about the window.
Steve
On Thu, Dec 15, 2011 at 10:05 PM, Joaquim Luis <jl...@ualg.pt> wrote:
>
>
>> float pafLocalMin = afWin[0];
>> float pafLocalMax = afWin[0];
>>
>> for ( int k = 1; k < 9; k++)
>> {
>> if (afWin[k] < pafLocalMin)
>> {
>> pafLocalMin=afWin[k];
>> }
>>
>> if (afWin[k] > pafLocalMax)
>> {
>> pafLocalMax=afWin[k];
>> }
>>
>> }
>>
>>
> key = afWin[4] - pafLocalMin;
>>
>> if (key < 0)
>> {
>> key = afWin[4] - pafLocalMax;
>> }
>>
>>
> Stephen
>
> 'key' can never be negative because pafLocalMin is computed from 'afWin'
> alone. The min val it can have is 0, when the minimum value is the central
> node itself.
>
> Joaquim
>
_______________________________________________
gdal-dev mailing list
gdal-dev@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/gdal-dev
