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/******************************************************************************
* $Id: gdalproximity.cpp 21167 2010-11-24 15:19:51Z warmerdam $
*
* Project: GDAL
* Purpose: Compute each pixel's proximity to a set of target pixels.
* Author: Frank Warmerdam, warmerdam@pobox.com
*
******************************************************************************
* Copyright (c) 2008, Frank Warmerdam
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
****************************************************************************/
#include "gdal_alg.h"
#include "cpl_conv.h"
#include "cpl_string.h"
CPL_CVSID("$Id: gdalproximity.cpp 21167 2010-11-24 15:19:51Z warmerdam $");
static CPLErr
ProcessProximityLine( GInt32 *panSrcScanline, int *panNearX, int *panNearY,
int bForward, int iLine, int nXSize, double nMaxDist,
float *pafProximity,
int nTargetValues, int *panTargetValues );
/************************************************************************/
/* GDALComputeProximity() */
/************************************************************************/
/**
Compute the proximity of all pixels in the image to a set of pixels in the source image.
This function attempts to compute the proximity of all pixels in
the image to a set of pixels in the source image. The following
options are used to define the behavior of the function. By
default all non-zero pixels in hSrcBand will be considered the
"target", and all proximities will be computed in pixels. Note
that target pixels are set to the value corresponding to a distance
of zero.
The progress function args may be NULL or a valid progress reporting function
such as GDALTermProgress/NULL.
Options:
VALUES=n[,n]*
A list of target pixel values to measure the distance from. If this
option is not provided proximity will be computed from non-zero
pixel values. Currently pixel values are internally processed as
integers.
DISTUNITS=[PIXEL]/GEO
Indicates whether distances will be computed in pixel units or
in georeferenced units. The default is pixel units. This also
determines the interpretation of MAXDIST.
MAXDIST=n
The maximum distance to search. Proximity distances greater than
this value will not be computed. Instead output pixels will be
set to a nodata value.
NODATA=n
The NODATA value to use on the output band for pixels that are
beyond MAXDIST. If not provided, the hProximityBand will be
queried for a nodata value. If one is not found, 65535 will be used.
FIXED_BUF_VAL=n
If this option is set, all pixels within the MAXDIST threadhold are
set to this fixed value instead of to a proximity distance.
*/
CPLErr CPL_STDCALL
GDALComputeProximity( GDALRasterBandH hSrcBand,
GDALRasterBandH hProximityBand,
char **papszOptions,
GDALProgressFunc pfnProgress,
void * pProgressArg )
{
int nXSize, nYSize, i, bFixedBufVal = FALSE;
const char *pszOpt;
double dfMaxDist;
double dfFixedBufVal = 0.0;
VALIDATE_POINTER1( hSrcBand, "GDALComputeProximity", CE_Failure );
VALIDATE_POINTER1( hProximityBand, "GDALComputeProximity", CE_Failure );
if( pfnProgress == NULL )
pfnProgress = GDALDummyProgress;
/* -------------------------------------------------------------------- */
/* Are we using pixels or georeferenced coordinates for distances? */
/* -------------------------------------------------------------------- */
double dfDistMult = 1.0;
pszOpt = CSLFetchNameValue( papszOptions, "DISTUNITS" );
if( pszOpt )
{
if( EQUAL(pszOpt,"GEO") )
{
GDALDatasetH hSrcDS = GDALGetBandDataset( hSrcBand );
if( hSrcDS )
{
double adfGeoTransform[6];
GDALGetGeoTransform( hSrcDS, adfGeoTransform );
if( ABS(adfGeoTransform[1]) != ABS(adfGeoTransform[5]) )
CPLError( CE_Warning, CPLE_AppDefined,
"Pixels not square, distances will be inaccurate." );
dfDistMult = ABS(adfGeoTransform[1]);
}
}
else if( !EQUAL(pszOpt,"PIXEL") )
{
CPLError( CE_Failure, CPLE_AppDefined,
"Unrecognised DISTUNITS value '%s', should be GEO or PIXEL.",
pszOpt );
return CE_Failure;
}
}
/* -------------------------------------------------------------------- */
/* What is our maxdist value? */
/* -------------------------------------------------------------------- */
pszOpt = CSLFetchNameValue( papszOptions, "MAXDIST" );
if( pszOpt )
dfMaxDist = atof(pszOpt) / dfDistMult;
else
dfMaxDist = GDALGetRasterBandXSize(hSrcBand) + GDALGetRasterBandYSize(hSrcBand);
CPLDebug( "GDAL", "MAXDIST=%g, DISTMULT=%g", dfMaxDist, dfDistMult );
/* -------------------------------------------------------------------- */
/* Verify the source and destination are compatible. */
/* -------------------------------------------------------------------- */
nXSize = GDALGetRasterBandXSize( hSrcBand );
nYSize = GDALGetRasterBandYSize( hSrcBand );
if( nXSize != GDALGetRasterBandXSize( hProximityBand )
|| nYSize != GDALGetRasterBandYSize( hProximityBand ))
{
CPLError( CE_Failure, CPLE_AppDefined,
"Source and proximity bands are not the same size." );
return CE_Failure;
}
/* -------------------------------------------------------------------- */
/* Get output NODATA value. */
/* -------------------------------------------------------------------- */
float fNoDataValue;
pszOpt = CSLFetchNameValue( papszOptions, "NODATA" );
if( pszOpt != NULL )
fNoDataValue = (float) atof(pszOpt);
else
{
int bSuccess;
fNoDataValue = (float) GDALGetRasterNoDataValue( hProximityBand, &bSuccess );
if( !bSuccess )
fNoDataValue = 65535.0;
}
/* -------------------------------------------------------------------- */
/* Is there a fixed value we wish to force the buffer area to? */
/* -------------------------------------------------------------------- */
pszOpt = CSLFetchNameValue( papszOptions, "FIXED_BUF_VAL" );
if( pszOpt )
{
dfFixedBufVal = atof(pszOpt);
bFixedBufVal = TRUE;
}
/* -------------------------------------------------------------------- */
/* Get the target value(s). */
/* -------------------------------------------------------------------- */
int *panTargetValues = NULL;
int nTargetValues = 0;
pszOpt = CSLFetchNameValue( papszOptions, "VALUES" );
if( pszOpt != NULL )
{
char **papszValuesTokens;
papszValuesTokens = CSLTokenizeStringComplex( pszOpt, ",", FALSE,FALSE);
nTargetValues = CSLCount(papszValuesTokens);
panTargetValues = (int *) CPLCalloc(sizeof(int),nTargetValues);
for( i = 0; i < nTargetValues; i++ )
panTargetValues[i] = atoi(papszValuesTokens[i]);
CSLDestroy( papszValuesTokens );
}
/* -------------------------------------------------------------------- */
/* Initialize progress counter. */
/* -------------------------------------------------------------------- */
if( !pfnProgress( 0.0, "", pProgressArg ) )
{
CPLError( CE_Failure, CPLE_UserInterrupt, "User terminated" );
CPLFree(panTargetValues);
return CE_Failure;
}
/* -------------------------------------------------------------------- */
/* We need a signed type for the working proximity values kept */
/* on disk. If our proximity band is not signed, then create a */
/* temporary file for this purpose. */
/* -------------------------------------------------------------------- */
GDALRasterBandH hWorkProximityBand = hProximityBand;
GDALDatasetH hWorkProximityDS = NULL;
GDALDataType eProxType = GDALGetRasterDataType( hProximityBand );
int *panNearX = NULL, *panNearY = NULL;
float *pafProximity = NULL;
GInt32 *panSrcScanline = NULL;
int iLine;
CPLErr eErr = CE_None;
if( eProxType == GDT_Byte
|| eProxType == GDT_UInt16
|| eProxType == GDT_UInt32 )
{
GDALDriverH hDriver = GDALGetDriverByName("GTiff");
if (hDriver == NULL)
{
CPLError(CE_Failure, CPLE_AppDefined,
"GDALComputeProximity needs GTiff driver");
eErr = CE_Failure;
goto end;
}
CPLString osTmpFile = CPLGenerateTempFilename( "proximity" );
hWorkProximityDS =
GDALCreate( hDriver, osTmpFile,
nXSize, nYSize, 1, GDT_Float32, NULL );
if (hWorkProximityDS == NULL)
{
eErr = CE_Failure;
goto end;
}
hWorkProximityBand = GDALGetRasterBand( hWorkProximityDS, 1 );
}
/* -------------------------------------------------------------------- */
/* Allocate buffer for two scanlines of distances as floats */
/* (the current and last line). */
/* -------------------------------------------------------------------- */
pafProximity = (float *) VSIMalloc2(sizeof(float), nXSize);
panNearX = (int *) VSIMalloc2(sizeof(int), nXSize);
panNearY = (int *) VSIMalloc2(sizeof(int), nXSize);
panSrcScanline = (GInt32 *) VSIMalloc2(sizeof(GInt32), nXSize);
if( pafProximity== NULL
|| panNearX == NULL
|| panNearY == NULL
|| panSrcScanline == NULL)
{
CPLError( CE_Failure, CPLE_OutOfMemory,
"Out of memory allocating working buffers.");
eErr = CE_Failure;
goto end;
}
/* -------------------------------------------------------------------- */
/* Loop from top to bottom of the image. */
/* -------------------------------------------------------------------- */
for( i = 0; i < nXSize; i++ )
panNearX[i] = panNearY[i] = -1;
for( iLine = 0; eErr == CE_None && iLine < nYSize; iLine++ )
{
// Read for target values.
eErr = GDALRasterIO( hSrcBand, GF_Read, 0, iLine, nXSize, 1,
panSrcScanline, nXSize, 1, GDT_Int32, 0, 0 );
if( eErr != CE_None )
break;
for( i = 0; i < nXSize; i++ )
pafProximity[i] = -1.0;
// Left to right
ProcessProximityLine( panSrcScanline, panNearX, panNearY,
TRUE, iLine, nXSize, dfMaxDist,
pafProximity, nTargetValues, panTargetValues );
// Right to Left
ProcessProximityLine( panSrcScanline, panNearX, panNearY,
FALSE, iLine, nXSize, dfMaxDist,
pafProximity, nTargetValues, panTargetValues );
// Write out results.
eErr =
GDALRasterIO( hWorkProximityBand, GF_Write, 0, iLine, nXSize, 1,
pafProximity, nXSize, 1, GDT_Float32, 0, 0 );
if( eErr != CE_None )
break;
if( !pfnProgress( 0.5 * (iLine+1) / (double) nYSize,
"", pProgressArg ) )
{
CPLError( CE_Failure, CPLE_UserInterrupt, "User terminated" );
eErr = CE_Failure;
}
}
/* -------------------------------------------------------------------- */
/* Loop from bottom to top of the image. */
/* -------------------------------------------------------------------- */
for( i = 0; i < nXSize; i++ )
panNearX[i] = panNearY[i] = -1;
for( iLine = nYSize-1; eErr == CE_None && iLine >= 0; iLine-- )
{
// Read first pass proximity
eErr =
GDALRasterIO( hWorkProximityBand, GF_Read, 0, iLine, nXSize, 1,
pafProximity, nXSize, 1, GDT_Float32, 0, 0 );
if( eErr != CE_None )
break;
// Read pixel values.
eErr = GDALRasterIO( hSrcBand, GF_Read, 0, iLine, nXSize, 1,
panSrcScanline, nXSize, 1, GDT_Int32, 0, 0 );
if( eErr != CE_None )
break;
// Right to left
ProcessProximityLine( panSrcScanline, panNearX, panNearY,
FALSE, iLine, nXSize, dfMaxDist,
pafProximity, nTargetValues, panTargetValues );
// Left to right
ProcessProximityLine( panSrcScanline, panNearX, panNearY,
TRUE, iLine, nXSize, dfMaxDist,
pafProximity, nTargetValues, panTargetValues );
// Final post processing of distances.
for( i = 0; i < nXSize; i++ )
{
if( pafProximity[i] < 0.0 )
pafProximity[i] = fNoDataValue;
else if( pafProximity[i] > 0.0 )
{
if( bFixedBufVal )
pafProximity[i] = (float) dfFixedBufVal;
else
pafProximity[i] = (float)(pafProximity[i] * dfDistMult);
}
}
// Write out results.
eErr =
GDALRasterIO( hProximityBand, GF_Write, 0, iLine, nXSize, 1,
pafProximity, nXSize, 1, GDT_Float32, 0, 0 );
if( eErr != CE_None )
break;
if( !pfnProgress( 0.5 + 0.5 * (nYSize-iLine) / (double) nYSize,
"", pProgressArg ) )
{
CPLError( CE_Failure, CPLE_UserInterrupt, "User terminated" );
eErr = CE_Failure;
}
}
/* -------------------------------------------------------------------- */
/* Cleanup */
/* -------------------------------------------------------------------- */
end:
CPLFree( panNearX );
CPLFree( panNearY );
CPLFree( panSrcScanline );
CPLFree( pafProximity );
CPLFree(panTargetValues);
if( hWorkProximityDS != NULL )
{
CPLString osProxFile = GDALGetDescription( hWorkProximityDS );
GDALClose( hWorkProximityDS );
GDALDeleteDataset( GDALGetDriverByName( "GTiff" ), osProxFile );
}
return eErr;
}
/************************************************************************/
/* ProcessProximityLine() */
/************************************************************************/
static CPLErr
ProcessProximityLine( GInt32 *panSrcScanline, int *panNearX, int *panNearY,
int bForward, int iLine, int nXSize, double dfMaxDist,
float *pafProximity,
int nTargetValues, int *panTargetValues )
{
int iStart, iEnd, iStep, iPixel;
if( bForward )
{
iStart = 0;
iEnd = nXSize;
iStep = 1;
}
else
{
iStart = nXSize-1;
iEnd = -1;
iStep = -1;
}
for( iPixel = iStart; iPixel != iEnd; iPixel += iStep )
{
int bIsTarget = FALSE;
/* -------------------------------------------------------------------- */
/* Is the current pixel a target pixel? */
/* -------------------------------------------------------------------- */
if( nTargetValues == 0 )
bIsTarget = (panSrcScanline[iPixel] != 0);
else
{
int i;
for( i = 0; i < nTargetValues; i++ )
{
if( panSrcScanline[iPixel] == panTargetValues[i] )
bIsTarget = TRUE;
}
}
if( bIsTarget )
{
pafProximity[iPixel] = 0.0;
panNearX[iPixel] = iPixel;
panNearY[iPixel] = iLine;
continue;
}
/* -------------------------------------------------------------------- */
/* Are we near(er) to the closest target to the above (below) */
/* pixel? */
/* -------------------------------------------------------------------- */
float fNearDistSq = (float) (MAX(dfMaxDist,nXSize) * MAX(dfMaxDist,nXSize) * 2);
float fDistSq;
if( panNearX[iPixel] != -1 )
{
fDistSq = (float)
((panNearX[iPixel] - iPixel) * (panNearX[iPixel] - iPixel)
+ (panNearY[iPixel] - iLine) * (panNearY[iPixel] - iLine));
if( fDistSq < fNearDistSq )
{
fNearDistSq = fDistSq;
}
else
{
panNearX[iPixel] = -1;
panNearY[iPixel] = -1;
}
}
/* -------------------------------------------------------------------- */
/* Are we near(er) to the closest target to the left (right) */
/* pixel? */
/* -------------------------------------------------------------------- */
int iLast = iPixel-iStep;
if( iPixel != iStart && panNearX[iLast] != -1 )
{
fDistSq = (float)
((panNearX[iLast] - iPixel) * (panNearX[iLast] - iPixel)
+ (panNearY[iLast] - iLine) * (panNearY[iLast] - iLine));
if( fDistSq < fNearDistSq )
{
fNearDistSq = fDistSq;
panNearX[iPixel] = panNearX[iLast];
panNearY[iPixel] = panNearY[iLast];
}
}
/* -------------------------------------------------------------------- */
/* Are we near(er) to the closest target to the topright */
/* (bottom left) pixel? */
/* -------------------------------------------------------------------- */
int iTR = iPixel+iStep;
if( iTR != iEnd && panNearX[iTR] != -1 )
{
fDistSq = (float)
((panNearX[iTR] - iPixel) * (panNearX[iTR] - iPixel)
+ (panNearY[iTR] - iLine) * (panNearY[iTR] - iLine));
if( fDistSq < fNearDistSq )
{
fNearDistSq = fDistSq;
panNearX[iPixel] = panNearX[iTR];
panNearY[iPixel] = panNearY[iTR];
}
}
/* -------------------------------------------------------------------- */
/* Update our proximity value. */
/* -------------------------------------------------------------------- */
if( panNearX[iPixel] != -1
&& fNearDistSq <= dfMaxDist * dfMaxDist
&& (pafProximity[iPixel] < 0
|| fNearDistSq < pafProximity[iPixel] * pafProximity[iPixel]) )
pafProximity[iPixel] = sqrt(fNearDistSq);
}
return CE_None;
}
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