GDAL工具箱详解之gdalinfo.exe
GDAL自带的工具包含了众多的功能,可以看做是利用该开源库进行的典型开发案例。本节主要介绍其中基本的一项工具——gdalinfo.exe。
- 该工具箱位于GDAL文件夹下的apps文件夹中,属于命令行可执行程序。
目录
使用方法
GDAL帮助文件中栅格工具箱里关于gdalinfo.exe的描述如下:
gdalinfo [--help-general] [-json] [-mm] [-stats] [-hist] [-nogcp] [-nomd]
[-norat] [-noct] [-nofl] [-checksum] [-proj4]
[-listmdd] [-mdd domain|`all`]*
[-sd subdataset] [-oo NAME=VALUE]* datasetname
项目 | 作用 |
---|---|
–help | 显示帮助 |
-general | 常规项目 |
-json | 标记是否以json形式输出 |
-mm | 标记是否强制计算每波段的MAX及MIN |
-stats | 标记读取图像统计信息(如果没有将从图像中计算) |
-hist | 标记报告所有波段的直方图信息 |
-nogcp | 标记不显示图像包含的地面控制点 |
-nomd | 标记不显示元数据 |
-norat | 标记不显示栅格属性表 |
-noct | 标记不显示色彩表 |
-checksum | 强制计算波段的校验码 |
-listmdd | 列出数据集可获得的所有元数据 |
-mdd domain | 获取特定所属的元数据 |
-nofl | 只显示文件列表中的第一个文件 |
-sd subdataset | 如果数据集包含了子集,该项用于指定要获取的子项。 |
-proj4 | 以PROJ4字符串形式显示图像的地理坐标系 |
-oo NAME=VALUE | 打开选项(以“选项名=选项值”进行设定) |
常规项目的内容
在命令行界面转到可执行程序目录,输入如下命令:
(Path of gdalinfo.exe)gdalinfo --help-general
得到输出
Generic GDAL utility command options:
--version: report version of GDAL in use.
--license: report GDAL license info.
--formats: report all configured format drivers.
--format [format]: details of one format.
--optfile filename: expand an option file into the argument list.
--config key value: set system configuration option.
--debug [on/off/value]: set debug level.
--pause: wait for user input, time to attach debugger
--locale [locale]: install locale for debugging (i.e. en_US.UTF-8)
--help-general: report detailed help on general options.
典例
下面是使用该程序的一个典型例子:
(Path of gdalinfo.exe)>gdalinfo -proj4 -stats ~\exmaple.tif
得到输出为:
Driver: GTiff/GeoTIFF
Files: E:\exmaple.tif
Size is 200, 400
Coordinate System is:
GEOGCS["WGS 84",
DATUM["WGS_1984",
SPHEROID["WGS 84",6378137,298.257223563,
AUTHORITY["EPSG","7030"]],
AUTHORITY["EPSG","6326"]],
PRIMEM["Greenwich",0],
UNIT["degree",0.0174532925199433],
AUTHORITY["EPSG","4326"]]
PROJ.4 string is:
'+proj=longlat +datum=WGS84 +no_defs '
Origin = (116.438654182485010,40.154364985586007)
Pixel Size = (0.000018000000000,-0.000018000000000)
Metadata:
AREA_OR_POINT=Area
Image Structure Metadata:
INTERLEAVE=PIXEL
Corner Coordinates:
Upper Left ( 116.4386542, 40.1543650)
Lower Left ( 116.4386542, 40.1471650)
Upper Right ( 116.4422542, 40.1543650)
Lower Right ( 116.4422542, 40.1471650)
Center ( 116.4404542, 40.1507650)
Band 1 Block=200x5 Type=UInt16, ColorInterp=Gray
Minimum=0.000, Maximum=0.000, Mean=0.000, StdDev=0.000
Metadata:
STATISTICS_MAXIMUM=0
STATISTICS_MEAN=0
STATISTICS_MINIMUM=0
STATISTICS_STDDEV=0
Band 2 Block=200x5 Type=UInt16, ColorInterp=Undefined
Minimum=0.000, Maximum=0.000, Mean=0.000, StdDev=0.000
Metadata:
STATISTICS_MAXIMUM=0
STATISTICS_MEAN=0
STATISTICS_MINIMUM=0
STATISTICS_STDDEV=0
Band 3 Block=200x5 Type=UInt16, ColorInterp=Undefined
Minimum=0.000, Maximum=0.000, Mean=0.000, StdDev=0.000
Metadata:
STATISTICS_MAXIMUM=0
STATISTICS_MEAN=0
STATISTICS_MINIMUM=0
STATISTICS_STDDEV=0
Band 4 Block=200x5 Type=UInt16, ColorInterp=Undefined
Minimum=0.000, Maximum=0.000, Mean=0.000, StdDev=0.000
Metadata:
STATISTICS_MAXIMUM=0
STATISTICS_MEAN=0
STATISTICS_MINIMUM=0
STATISTICS_STDDEV=0
这里使用的例子数据是一份实验数据,实际上带有信息的图像的统计信息不会全为0。
源码分析
那么gdalinfo是如何工作的呢,虽然有帮助的提示,我们还有很多选项不知道如何设定,比如:–oo中的NAME=VALUE存在哪些项目和可选项呢?这些选项的默认参数又是什么呢?下面我们就从源码角度来分析该应用程序是如何工作的。
源码及分析
int main( int argc, char ** argv )
{
EarlySetConfigOptions(argc, argv);//预设置
GDALAllRegister();//注册所有驱动
argc = GDALGeneralCmdLineProcessor( argc, &argv, 0 );//命令行参数处理
if( argc < 1 )//如果参数小于1,程序退出
exit( -argc );
for( int i = 0; argv != NULL && argv[i] != NULL; i++ )//参数匹配
{
if( EQUAL(argv[i], "--utility_version") )
{//打印工具版本
printf("%s was compiled against GDAL %s and is running against GDAL %s\n",
argv[0], GDAL_RELEASE_NAME, GDALVersionInfo("RELEASE_NAME"));
CSLDestroy( argv );
return 0;
}
else if( EQUAL(argv[i],"--help") )
{//打印帮助,并退出
Usage();
}
}
argv = CSLAddString(argv, "-stdout");//设置标准输出
GDALInfoOptionsForBinary* psOptionsForBinary = GDALInfoOptionsForBinaryNew();//初始化二值化选项
GDALInfoOptions *psOptions
= GDALInfoOptionsNew(argv + 1, psOptionsForBinary);//**根据字符串数组初始化要显示的信息选项**
if( psOptions == NULL )//如果选项初始化失败,退出
Usage();
if( psOptionsForBinary->pszFilename == NULL )//如果没有指定资源文件,退出
Usage("No datasource specified.");
/* -------------------------------------------------------------------- */
/* 打开数据集. */
/* -------------------------------------------------------------------- */
#ifdef __AFL_HAVE_MANUAL_CONTROL
//**配合下面**
int iIter = 0;
while (__AFL_LOOP(1000)) {
iIter ++;
#endif
GDALDatasetH hDataset
= GDALOpenEx( psOptionsForBinary->pszFilename, GDAL_OF_READONLY | GDAL_OF_RASTER | GDAL_OF_VERBOSE_ERROR, NULL,
(const char* const* )psOptionsForBinary->papszOpenOptions, NULL );//打开数据集
if( hDataset == NULL )
{
#ifdef __AFL_HAVE_MANUAL_CONTROL
continue;
#else
fprintf( stderr,
"gdalinfo failed - unable to open '%s'.\n",
psOptionsForBinary->pszFilename );
/* -------------------------------------------------------------------- */
/* 如果参数是一个VSI文件, 就打印其内容。 */
/* -------------------------------------------------------------------- */
if ( STARTS_WITH(psOptionsForBinary->pszFilename, "/vsizip/") ||
STARTS_WITH(psOptionsForBinary->pszFilename, "/vsitar/") )
{
char** papszFileList = VSIReadDirRecursive( psOptionsForBinary->pszFilename );
if ( papszFileList )
{
int nCount = CSLCount( papszFileList );
fprintf( stdout,
"Unable to open source `%s' directly.\n"
"The archive contains %d files:\n",
psOptionsForBinary->pszFilename, nCount );
for ( int i = 0; i < nCount; i++ )
{//打印内部文件列表
fprintf( stdout, " %s/%s\n", psOptionsForBinary->pszFilename, papszFileList[i] );
}
CSLDestroy( papszFileList );
}
}
CSLDestroy( argv );//释放参数
GDALInfoOptionsForBinaryFree(psOptionsForBinary);//释放二值化选项
GDALInfoOptionsFree( psOptions );//释放选项占用的内存
GDALDumpOpenDatasets( stderr );//释放打开的数据集
GDALDestroyDriverManager();//释放驱动管理
CPLDumpSharedList( NULL );
exit( 1 );
#endif
}
/* -------------------------------------------------------------------- */
/* 读取特定的文件子数据集. */
/* -------------------------------------------------------------------- */
if ( psOptionsForBinary->nSubdataset > 0 )
{
char **papszSubdatasets = GDALGetMetadata( hDataset, "SUBDATASETS" );
int nSubdatasets = CSLCount( papszSubdatasets );
if ( nSubdatasets > 0 && psOptionsForBinary->nSubdataset <= nSubdatasets )
{
char szKeyName[1024];
char *pszSubdatasetName;
snprintf( szKeyName, sizeof(szKeyName),
"SUBDATASET_%d_NAME", psOptionsForBinary->nSubdataset );
szKeyName[sizeof(szKeyName) - 1] = '\0';
pszSubdatasetName =
CPLStrdup( CSLFetchNameValue( papszSubdatasets, szKeyName ) );
GDALClose( hDataset );//关闭原数据集
hDataset = GDALOpen( pszSubdatasetName, GA_ReadOnly );//打开子数据集
CPLFree( pszSubdatasetName );
}
else
{
fprintf( stderr,
"gdalinfo warning: subdataset %d of %d requested. "
"Reading the main dataset.\n",
psOptionsForBinary->nSubdataset, nSubdatasets );
}
}
char* pszGDALInfoOutput = GDALInfo( hDataset, psOptions );//**核心函数,读取数据集信息**
if( pszGDALInfoOutput )//读取成功则输出
printf( "%s", pszGDALInfoOutput );
CPLFree( pszGDALInfoOutput );//释放输出字符串
GDALClose( hDataset );//关闭数据集
#ifdef __AFL_HAVE_MANUAL_CONTROL
}//**配合上面,组成循环**
#endif
GDALInfoOptionsForBinaryFree(psOptionsForBinary);//释放二值化选项
GDALInfoOptionsFree( psOptions );//释放选项
CSLDestroy( argv );//释放输入参数
GDALDumpOpenDatasets( stderr );//释放打开数据集
GDALDestroyDriverManager();//释放驱动管理
CPLDumpSharedList( NULL );
CPLCleanupTLS();
exit( 0 );
}
流程图
从以上流程图可以看出,本程序的核心函数为GDALInfo(GDALDatasetH hDataset,
const GDALInfoOptions * psOptions )
前面大量的工作用来增强程序对多种输入的适应性和构筑信息选项。
参数初始化
参数初始化函数GDALInfoOptionsForBinaryNew()以及GDALInfoOptionsNew()是如何设置默认选项的呢,我们定位到函数体:
static GDALInfoOptionsForBinary *GDALInfoOptionsForBinaryNew(void)
{
return (GDALInfoOptionsForBinary*) CPLCalloc( 1, sizeof(GDALInfoOptionsForBinary) );
}
很显然,二值化信息选项只是申请了内存并且返回指针。
GDALInfoOptions *GDALInfoOptionsNew(char** papszArgv,
GDALInfoOptionsForBinary* psOptionsForBinary)
{
bool bGotFilename = false;
GDALInfoOptions *psOptions = static_cast<GDALInfoOptions *>(
CPLCalloc( 1, sizeof(GDALInfoOptions) ) );//申请内存
psOptions->eFormat = GDALINFO_FORMAT_TEXT;//默认以文本形式输出
psOptions->bComputeMinMax = FALSE;//默认不计算最大最小值
psOptions->bReportHistograms = FALSE;//默认不报告直方图
psOptions->bReportProj4 = FALSE;//默认不以PROJ4字符报告
psOptions->bStats = FALSE;//默认不统计波段信息
psOptions->bApproxStats = TRUE;//默认开启粗略统计
psOptions->bSample = FALSE;//默认不采样
psOptions->bComputeChecksum = FALSE;//默认不检校
psOptions->bShowGCPs = TRUE;//默认显示控制点
psOptions->bShowMetadata = TRUE;//默认显示主文件元数据
psOptions->bShowRAT = TRUE;//默认显示栅格属性表
psOptions->bShowColorTable = TRUE;//默认显示颜色表
psOptions->bListMDD = FALSE;//默认不显示元数据列表
psOptions->bShowFileList = TRUE;//默认显示文件列表
/* -------------------------------------------------------------------- */
/* 传参. */
/* -------------------------------------------------------------------- */
for( int i = 0; papszArgv != NULL && papszArgv[i] != NULL; i++ )
{
if( EQUAL(papszArgv[i],"-json") )
psOptions->eFormat = GDALINFO_FORMAT_JSON;
else if( EQUAL(papszArgv[i], "-mm") )
psOptions->bComputeMinMax = TRUE;
else if( EQUAL(papszArgv[i], "-hist") )
psOptions->bReportHistograms = TRUE;
else if( EQUAL(papszArgv[i], "-proj4") )
psOptions->bReportProj4 = TRUE;
else if( EQUAL(papszArgv[i], "-stats") )
{
psOptions->bStats = TRUE;
psOptions->bApproxStats = FALSE;
}
else if( EQUAL(papszArgv[i], "-approx_stats") )
{
psOptions->bStats = TRUE;
psOptions->bApproxStats = TRUE;
}
else if( EQUAL(papszArgv[i], "-sample") )
psOptions->bSample = TRUE;
else if( EQUAL(papszArgv[i], "-checksum") )
psOptions->bComputeChecksum = TRUE;
else if( EQUAL(papszArgv[i], "-nogcp") )
psOptions->bShowGCPs = FALSE;
else if( EQUAL(papszArgv[i], "-nomd") )
psOptions->bShowMetadata = FALSE;
else if( EQUAL(papszArgv[i], "-norat") )
psOptions->bShowRAT = FALSE;
else if( EQUAL(papszArgv[i], "-noct") )
psOptions->bShowColorTable = FALSE;
else if( EQUAL(papszArgv[i], "-listmdd") )
psOptions->bListMDD = TRUE;
/* Not documented: used by gdalinfo_bin.cpp only */
else if( EQUAL(papszArgv[i], "-stdout") )
psOptions->bStdoutOutput = true;
else if( EQUAL(papszArgv[i], "-mdd") && papszArgv[i+1] != NULL )
{//设定要获取的属于该文件的元数据
psOptions->papszExtraMDDomains = CSLAddString(
psOptions->papszExtraMDDomains, papszArgv[++i] );
}
else if( EQUAL(papszArgv[i], "-oo") && papszArgv[i+1] != NULL )
{//设定属性
i++;
if( psOptionsForBinary )
{
psOptionsForBinary->papszOpenOptions = CSLAddString(
psOptionsForBinary->papszOpenOptions, papszArgv[i] );
}
}
else if( EQUAL(papszArgv[i], "-nofl") )
psOptions->bShowFileList = FALSE;
else if( EQUAL(papszArgv[i], "-sd") && papszArgv[i+1] != NULL )
{//子数据集
i++;
if( psOptionsForBinary )
{
psOptionsForBinary->nSubdataset = atoi(papszArgv[i]);
}
}
else if( papszArgv[i][0] == '-' )
{//错误选项处理
CPLError(CE_Failure, CPLE_NotSupported,
"Unknown option name '%s'", papszArgv[i]);
GDALInfoOptionsFree(psOptions);
return NULL;
}
else if( !bGotFilename )
{//输入文件名称
bGotFilename = true;
if( psOptionsForBinary )
psOptionsForBinary->pszFilename = CPLStrdup(papszArgv[i]);
}
else
{
CPLError(CE_Failure, CPLE_NotSupported,
"Too many command options '%s'", papszArgv[i]);
GDALInfoOptionsFree(psOptions);
return NULL;
}
}
return psOptions;
}
从上面的源码我们可以得到一些处理命令行程序参数输入的小技巧,如-oo和文件名的指定,也清楚了默认文件打开参数和信息显示选项值。但必须注意的是,这里对于-oo的处理仅是将NMAE=VALUE加入OpenOptions字符串数组中,那么问题就转变成了如何根据这个字符串数组进行有效性判断!
没错,再次将视线转向GDALOpenEx(const char* pszFilename,unsigned int nOpenFlags, const char* const* papszAllowedDrivers, const char* const* papszOpenOptions,const char* const* papszSiblingFiles)函数。注意到帮助里的描述:
* @param papszOpenOptions NULL, or a NULL terminated list of strings with open
* options passed to candidate drivers. An option exists for all drivers,
* OVERVIEW_LEVEL=level, to select a particular overview level of a dataset.
* The level index starts at 0. The level number can be suffixed by "only" to specify that
* only this overview level must be visible, and not sub-levels.
* Open options are validated by default, and a warning is emitted in case the
* option is not recognized. In some scenarios, it might be not desirable (e.g.
* when not knowing which driver will open the file), so the special open option
* VALIDATE_OPEN_OPTIONS can be set to NO to avoid such warnings. Alternatively,
* since GDAL 2.1, an option name can be preceded by the @ character to indicate
* that it may not cause a warning if the driver doesn't declare this option.
经过几步,最后定义到有效性检验函数体:
int GDALValidateOpenOptions( GDALDriverH hDriver,
const char* const* papszOpenOptions)
{
VALIDATE_POINTER1( hDriver, "GDALValidateOpenOptions", FALSE );
const char *pszOptionList =
((GDALDriver *) hDriver)->GetMetadataItem( GDAL_DMD_OPENOPTIONLIST );
CPLString osDriver;
osDriver.Printf("driver %s", ((GDALDriver *) hDriver)->GetDescription());
return GDALValidateOptions( pszOptionList, papszOpenOptions,
"open option",
osDriver);
}
可以看出该打开选项依赖于图像驱动的不同而变化,通过该驱动的GetMetadataItem()方法可以得到驱动所支持的打开选项列表。
这里还存在一个问题,GDAL_DMD_OPENOPTIONLIST
是一个定义项,其值为"DMD_OPENOPTIONLIST"
,然而在内部进行跟踪时别没有发现它是如何获得选项列表的。不过对帮助进行查看我们发现存在
char ** VRTDriver::GetMetadata ( const char * pszDomain = "" )
可以获得驱动的元数据列表,但同样是虚方法,根据具体驱动实现不同。
读取信息主函数
先上源码:
char *GDALInfo( GDALDatasetH hDataset, const GDALInfoOptions *psOptions )
{
if( hDataset == NULL )
return NULL;
GDALInfoOptions* psOptionsToFree = NULL;
if( psOptions == NULL )
{//初始化信息选项
psOptionsToFree = GDALInfoOptionsNew(NULL, NULL);
psOptions = psOptionsToFree;
}
CPLString osStr;
json_object *poJsonObject = NULL, *poBands = NULL, *poMetadata = NULL;
const bool bJson = psOptions->eFormat == GDALINFO_FORMAT_JSON;//先判断后赋值
/* -------------------------------------------------------------------- */
/* 报告通常信息. */
/* -------------------------------------------------------------------- */
GDALDriverH hDriver = GDALGetDatasetDriver( hDataset );//获取驱动
if(bJson)
{
json_object *poDescription = json_object_new_string(GDALGetDescription(hDataset));//获取描述
json_object *poDriverShortName = json_object_new_string(GDALGetDriverShortName(hDriver));//驱动简称
json_object *poDriverLongName = json_object_new_string(GDALGetDriverLongName(hDriver));//驱动全称
poJsonObject = json_object_new_object();
poBands = json_object_new_array();
poMetadata = json_object_new_object();
json_object_object_add(poJsonObject, "description", poDescription);
json_object_object_add(poJsonObject, "driverShortName", poDriverShortName);
json_object_object_add(poJsonObject, "driverLongName", poDriverLongName);
}
else
{
Concat( osStr, psOptions->bStdoutOutput, "Driver: %s/%s\n",
GDALGetDriverShortName( hDriver ),
GDALGetDriverLongName( hDriver ) );
}//这是一个链接输出项目形成输出字符串的函数
char **papszFileList = GDALGetFileList( hDataset );
if( papszFileList == NULL || *papszFileList == NULL )
{
if(bJson)
{
json_object *poFiles = json_object_new_array();
json_object_object_add(poJsonObject, "files", poFiles);//文件列表json
}
else
Concat( osStr, psOptions->bStdoutOutput,
"Files: none associated\n" );
}
else
{
if(bJson)
{
if( psOptions->bShowFileList )
{
json_object *poFiles = json_object_new_array();
for(int i = 0; papszFileList[i] != NULL; i++)
{
json_object *poFile = json_object_new_string(papszFileList[i]);
json_object_array_add(poFiles, poFile);
}
json_object_object_add(poJsonObject, "files", poFiles);
}
}
else
{
Concat(osStr, psOptions->bStdoutOutput, "Files: %s\n", papszFileList[0] );
if( psOptions->bShowFileList )
{
for( int i = 1; papszFileList[i] != NULL; i++ )
Concat(osStr, psOptions->bStdoutOutput, " %s\n", papszFileList[i] );
}
}
}
CSLDestroy( papszFileList );
if(bJson)
{
json_object *poSize = json_object_new_array();
json_object *poSizeX = json_object_new_int(GDALGetRasterXSize(hDataset));
json_object *poSizeY = json_object_new_int(GDALGetRasterYSize(hDataset));
json_object_array_add(poSize, poSizeX);
json_object_array_add(poSize, poSizeY);
json_object_object_add(poJsonObject, "size", poSize);
}
else
Concat(osStr, psOptions->bStdoutOutput, "Size is %d, %d\n", GDALGetRasterXSize( hDataset ),
GDALGetRasterYSize( hDataset ) );//栅格图像大小
/* -------------------------------------------------------------------- */
/* 报告投影信息. */
/* -------------------------------------------------------------------- */
if( GDALGetProjectionRef( hDataset ) != NULL )
{
json_object *poCoordinateSystem = NULL;
if(bJson)
poCoordinateSystem = json_object_new_object();
char *pszProjection
= const_cast<char *>( GDALGetProjectionRef( hDataset ) );
OGRSpatialReferenceH hSRS
= OSRNewSpatialReference(NULL);
if( OSRImportFromWkt( hSRS, &pszProjection ) == CE_None )//尝试转化OGR参考系
{
char *pszPrettyWkt = NULL;
OSRExportToPrettyWkt( hSRS, &pszPrettyWkt, FALSE );
if(bJson)
{
json_object *poWkt = json_object_new_string(pszPrettyWkt);
json_object_object_add(poCoordinateSystem, "wkt", poWkt);
}
else
Concat( osStr, psOptions->bStdoutOutput,
"Coordinate System is:\n%s\n",
pszPrettyWkt );
CPLFree( pszPrettyWkt );
}
else
{
if(bJson)
{
json_object *poWkt = json_object_new_string(GDALGetProjectionRef(hDataset));
json_object_object_add(poCoordinateSystem, "wkt", poWkt);
}
else
Concat( osStr, psOptions->bStdoutOutput,
"Coordinate System is `%s'\n",
GDALGetProjectionRef( hDataset ) );//直接输出
}
if ( psOptions->bReportProj4 )
{
char *pszProj4 = NULL;
OSRExportToProj4( hSRS, &pszProj4 );//转换为PROJ4格式
if(bJson)
{
json_object *proj4 = json_object_new_string(pszProj4);
json_object_object_add(poCoordinateSystem, "proj4", proj4);
}
else
Concat(osStr, psOptions->bStdoutOutput, "PROJ.4 string is:\n\'%s\'\n",pszProj4);
CPLFree( pszProj4 );
}
if(bJson)
json_object_object_add(poJsonObject, "coordinateSystem", poCoordinateSystem);
OSRDestroySpatialReference( hSRS );
}
/* -------------------------------------------------------------------- */
/* 报告地理转换参数. */
/* -------------------------------------------------------------------- */
double adfGeoTransform[6] = {0.0, 0.0, 0.0, 0.0, 0.0, 0.0};
if( GDALGetGeoTransform( hDataset, adfGeoTransform ) == CE_None )//地理转换参数赋值
{
if(bJson)
{
json_object *poGeoTransform = json_object_new_array();
for( int i = 0; i < 6; i++ )
{
json_object *poGeoTransformCoefficient = json_object_new_double_with_precision(adfGeoTransform[i], 16);
json_object_array_add(poGeoTransform, poGeoTransformCoefficient);
}
json_object_object_add(poJsonObject, "geoTransform", poGeoTransform);
}
else
{
if( adfGeoTransform[2] == 0.0 && adfGeoTransform[4] == 0.0 )
{//如果图像未旋转
Concat( osStr, psOptions->bStdoutOutput,
"Origin = (%.15f,%.15f)\n",
adfGeoTransform[0], adfGeoTransform[3] );//左上角像元地理坐标
Concat( osStr, psOptions->bStdoutOutput,
"Pixel Size = (%.15f,%.15f)\n",
adfGeoTransform[1], adfGeoTransform[5] );//像元大小
}
else
Concat( osStr, psOptions->bStdoutOutput, "GeoTransform =\n"
" %.16g, %.16g, %.16g\n"
" %.16g, %.16g, %.16g\n",
adfGeoTransform[0],
adfGeoTransform[1],
adfGeoTransform[2],
adfGeoTransform[3],
adfGeoTransform[4],
adfGeoTransform[5] );//顺序输出
}
}
/* -------------------------------------------------------------------- */
/* 报告地面控制点. */
/* -------------------------------------------------------------------- */
if( psOptions->bShowGCPs && GDALGetGCPCount( hDataset ) > 0 )
{
json_object * const poGCPs = bJson ? json_object_new_object() : NULL;
if (GDALGetGCPProjection(hDataset) != NULL)//获取地面控制点投影
{
json_object *poGCPCoordinateSystem = NULL;
char *pszProjection
= const_cast<char *>( GDALGetGCPProjection( hDataset ) );
OGRSpatialReferenceH hSRS
= OSRNewSpatialReference(NULL);
if( OSRImportFromWkt( hSRS, &pszProjection ) == CE_None )
{
char *pszPrettyWkt = NULL;
OSRExportToPrettyWkt( hSRS, &pszPrettyWkt, FALSE );
if(bJson)
{
json_object *poWkt = json_object_new_string(pszPrettyWkt);
poGCPCoordinateSystem = json_object_new_object();
json_object_object_add(poGCPCoordinateSystem, "wkt", poWkt);
}
else
Concat(osStr, psOptions->bStdoutOutput, "GCP Projection = \n%s\n", pszPrettyWkt );
CPLFree( pszPrettyWkt );
}
else
{
if(bJson)
{
json_object *poWkt = json_object_new_string(GDALGetGCPProjection(hDataset));
poGCPCoordinateSystem = json_object_new_object();
json_object_object_add(poGCPCoordinateSystem, "wkt", poWkt);
}
else
Concat(osStr, psOptions->bStdoutOutput, "GCP Projection = %s\n",
GDALGetGCPProjection( hDataset ) );
}
if(bJson)
json_object_object_add(poGCPs, "coordinateSystem", poGCPCoordinateSystem);
OSRDestroySpatialReference( hSRS );
}
json_object * const poGCPList = bJson ? json_object_new_array() : NULL;
for( int i = 0; i < GDALGetGCPCount(hDataset); i++ )
{
const GDAL_GCP *psGCP = GDALGetGCPs( hDataset ) + i;//地面控制点
if(bJson)
{
json_object *poGCP = json_object_new_object();
json_object *poId = json_object_new_string(psGCP->pszId);
json_object *poInfo = json_object_new_string(psGCP->pszInfo);
json_object *poPixel = json_object_new_double_with_precision(psGCP->dfGCPPixel, 15);
json_object *poLine = json_object_new_double_with_precision(psGCP->dfGCPLine, 15);
json_object *poX = json_object_new_double_with_precision(psGCP->dfGCPX, 15);
json_object *poY = json_object_new_double_with_precision(psGCP->dfGCPY, 15);
json_object *poZ = json_object_new_double_with_precision(psGCP->dfGCPZ, 15);
json_object_object_add(poGCP, "id", poId);
json_object_object_add(poGCP, "info", poInfo);
json_object_object_add(poGCP, "pixel", poPixel);
json_object_object_add(poGCP, "line", poLine);
json_object_object_add(poGCP, "x", poX);
json_object_object_add(poGCP, "y", poY);
json_object_object_add(poGCP, "z", poZ);
json_object_array_add(poGCPList, poGCP);
}
else
Concat(osStr, psOptions->bStdoutOutput, "GCP[%3d]: Id=%s, Info=%s\n"
" (%.15g,%.15g) -> (%.15g,%.15g,%.15g)\n",
i, psGCP->pszId, psGCP->pszInfo,
psGCP->dfGCPPixel, psGCP->dfGCPLine,
psGCP->dfGCPX, psGCP->dfGCPY, psGCP->dfGCPZ );//控制点信息输出
}
if(bJson)
{
json_object_object_add(poGCPs, "gcpList", poGCPList);
json_object_object_add(poJsonObject, "gcps", poGCPs);
}
}
/* -------------------------------------------------------------------- */
/* 报告数据集元数据. */
/* -------------------------------------------------------------------- */
GDALInfoReportMetadata( psOptions, hDataset, false, bJson, poMetadata, osStr );//元数据信息获取函数(数据集)
if(bJson)
{
if( psOptions->bShowMetadata )
json_object_object_add( poJsonObject, "metadata", poMetadata );
else
json_object_put(poMetadata);
}
/* -------------------------------------------------------------------- */
/* 如果合适,设置经纬度投影转换. */
/* -------------------------------------------------------------------- */
const char *pszProjection = NULL;
if( GDALGetGeoTransform( hDataset, adfGeoTransform ) == CE_None )
pszProjection = GDALGetProjectionRef(hDataset);
OGRCoordinateTransformationH hTransform = NULL;
OGRCoordinateTransformationH hTransformWGS84 = NULL;
if( pszProjection != NULL && strlen(pszProjection) > 0 )
{
OGRSpatialReferenceH hProj, hLatLong = NULL, hLatLongWGS84 = NULL;
hProj = OSRNewSpatialReference( pszProjection );
if( hProj != NULL )
{
hLatLong = OSRCloneGeogCS( hProj );
if(bJson)
{
hLatLongWGS84 = OSRNewSpatialReference( NULL );
OSRSetWellKnownGeogCS( hLatLongWGS84, "WGS84" );
}
}
if( hLatLong != NULL )
{
CPLPushErrorHandler( CPLQuietErrorHandler );
hTransform = OCTNewCoordinateTransformation( hProj, hLatLong );//坐标转换信息
CPLPopErrorHandler();
OSRDestroySpatialReference( hLatLong );
}
if( hLatLongWGS84 != NULL )
{
CPLPushErrorHandler( CPLQuietErrorHandler );
hTransformWGS84 = OCTNewCoordinateTransformation( hProj, hLatLongWGS84 );
CPLPopErrorHandler();
OSRDestroySpatialReference( hLatLongWGS84 );
}
if( hProj != NULL )
OSRDestroySpatialReference( hProj );
}
/* -------------------------------------------------------------------- */
/* 报告边角信息. */
/* -------------------------------------------------------------------- */
if(bJson)
{
json_object *poLinearRing = json_object_new_array();
json_object *poCornerCoordinates = json_object_new_object();
json_object *poWGS84Extent = json_object_new_object();
json_object *poWGS84ExtentType = json_object_new_string("Polygon");
json_object *poWGS84ExtentCoordinates = json_object_new_array();
GDALInfoReportCorner( psOptions, hDataset, hTransform, hTransformWGS84, "upperLeft",
0.0, 0.0, bJson, poCornerCoordinates, poWGS84ExtentCoordinates, osStr );//边角报告函数
GDALInfoReportCorner( psOptions, hDataset, hTransform, hTransformWGS84, "lowerLeft",
0.0, GDALGetRasterYSize(hDataset), bJson, poCornerCoordinates, poWGS84ExtentCoordinates, osStr );
GDALInfoReportCorner( psOptions, hDataset, hTransform, hTransformWGS84, "upperRight",
GDALGetRasterXSize(hDataset), 0.0, bJson, poCornerCoordinates, poWGS84ExtentCoordinates, osStr );
GDALInfoReportCorner( psOptions, hDataset, hTransform, hTransformWGS84, "lowerRight",
GDALGetRasterXSize(hDataset), GDALGetRasterYSize(hDataset),
bJson, poCornerCoordinates, poWGS84ExtentCoordinates, osStr );
GDALInfoReportCorner( psOptions, hDataset, hTransform, hTransformWGS84, "center",
GDALGetRasterXSize(hDataset)/2.0, GDALGetRasterYSize(hDataset)/2.0,
bJson, poCornerCoordinates, poWGS84ExtentCoordinates, osStr );
GDALInfoReportCorner( psOptions, hDataset, hTransform, hTransformWGS84, "upperLeft",
0.0, 0.0, bJson, poCornerCoordinates, poWGS84ExtentCoordinates, osStr );
json_object_object_add( poJsonObject, "cornerCoordinates", poCornerCoordinates );
json_object_object_add( poWGS84Extent, "type", poWGS84ExtentType );
json_object_array_add( poLinearRing, poWGS84ExtentCoordinates );
json_object_object_add( poWGS84Extent, "coordinates", poLinearRing );
json_object_object_add( poJsonObject, "wgs84Extent", poWGS84Extent );
}
else
{
Concat(osStr, psOptions->bStdoutOutput, "Corner Coordinates:\n" );
GDALInfoReportCorner( psOptions, hDataset, hTransform, hTransformWGS84, "Upper Left",
0.0, 0.0, bJson, NULL, NULL, osStr );
GDALInfoReportCorner( psOptions, hDataset, hTransform, hTransformWGS84, "Lower Left",
0.0, GDALGetRasterYSize(hDataset), bJson, NULL, NULL, osStr );
GDALInfoReportCorner( psOptions, hDataset, hTransform, hTransformWGS84, "Upper Right",
GDALGetRasterXSize(hDataset), 0.0, bJson, NULL, NULL, osStr );
GDALInfoReportCorner( psOptions, hDataset, hTransform, hTransformWGS84, "Lower Right",
GDALGetRasterXSize(hDataset),
GDALGetRasterYSize(hDataset), bJson, NULL, NULL, osStr );
GDALInfoReportCorner( psOptions, hDataset, hTransform, hTransformWGS84, "Center",
GDALGetRasterXSize(hDataset)/2.0,
GDALGetRasterYSize(hDataset)/2.0, bJson, NULL, NULL, osStr );
}
if( hTransform != NULL )
{
OCTDestroyCoordinateTransformation( hTransform );
hTransform = NULL;
}
if( hTransformWGS84 != NULL )
{
OCTDestroyCoordinateTransformation( hTransformWGS84 );
hTransformWGS84 = NULL;
}
/* ==================================================================== */
/* 循环处理波段. */
/* ==================================================================== */
for( int iBand = 0; iBand < GDALGetRasterCount( hDataset ); iBand++ )
{
json_object *poBand = NULL;
json_object *poBandMetadata = NULL;
if(bJson)
{
poBand = json_object_new_object();
poBandMetadata = json_object_new_object();
}
GDALRasterBandH const hBand = GDALGetRasterBand( hDataset, iBand+1 );
//获取波段
if( psOptions->bSample )
{//采样统计判断
vector<float> ofSample(10000, 0);
float * const pafSample = &ofSample[0];
const int nCount =
GDALGetRandomRasterSample( hBand, 10000, pafSample );//采样
if(!bJson)
Concat( osStr, psOptions->bStdoutOutput,
"Got %d samples.\n", nCount );
}
int nBlockXSize = 0;
int nBlockYSize = 0;
GDALGetBlockSize( hBand, &nBlockXSize, &nBlockYSize );//获取波段数据块大小
if(bJson)
{
json_object *poBandNumber = json_object_new_int(iBand+1);
json_object *poBlock = json_object_new_array();
json_object *poType = json_object_new_string(GDALGetDataTypeName(GDALGetRasterDataType(hBand)));//获取数据类型说明
json_object *poColorInterp = json_object_new_string(GDALGetColorInterpretationName(
GDALGetRasterColorInterpretation(hBand)));//获取波段说明
json_object_array_add(poBlock, json_object_new_int(nBlockXSize));
json_object_array_add(poBlock, json_object_new_int(nBlockYSize));
json_object_object_add(poBand, "band", poBandNumber);
json_object_object_add(poBand, "block", poBlock);
json_object_object_add(poBand, "type", poType);
json_object_object_add(poBand, "colorInterpretation", poColorInterp);
}
else
Concat( osStr, psOptions->bStdoutOutput,
"Band %d Block=%dx%d Type=%s, ColorInterp=%s\n",
iBand+1,
nBlockXSize, nBlockYSize,
GDALGetDataTypeName(
GDALGetRasterDataType(hBand)),
GDALGetColorInterpretationName(
GDALGetRasterColorInterpretation(hBand)) );
if( GDALGetDescription( hBand ) != NULL
&& strlen(GDALGetDescription( hBand )) > 0 )
{
if(bJson)
{
json_object *poBandDescription = json_object_new_string(GDALGetDescription(hBand));
json_object_object_add(poBand, "description", poBandDescription);
}
else
Concat( osStr, psOptions->bStdoutOutput, " Description = %s\n",
GDALGetDescription(hBand) );//波段说明
}
{
int bGotMin = FALSE;
int bGotMax = FALSE;
const double dfMin = GDALGetRasterMinimum( hBand, &bGotMin );//获取波段最小值
const double dfMax = GDALGetRasterMaximum( hBand, &bGotMax );//获取波段最大值
if( bGotMin || bGotMax || psOptions->bComputeMinMax )
{
if(!bJson)
Concat(osStr, psOptions->bStdoutOutput, " " );
if( bGotMin )
{
if(bJson)
{
json_object *poMin = json_object_new_double_with_precision(dfMin, 3);
json_object_object_add(poBand, "min", poMin);
}
else
Concat(osStr, psOptions->bStdoutOutput, "Min=%.3f ", dfMin );
}
if( bGotMax )
{
if(bJson)
{
json_object *poMax = json_object_new_double_with_precision(dfMax, 3);
json_object_object_add(poBand, "max", poMax);
}
else
Concat(osStr, psOptions->bStdoutOutput, "Max=%.3f ", dfMax );
}
if( psOptions->bComputeMinMax )
{
CPLErrorReset();
double adfCMinMax[2] = {0.0, 0.0};
GDALComputeRasterMinMax( hBand, FALSE, adfCMinMax );//强制计算波段最大最小值
if (CPLGetLastErrorType() == CE_None)
{
if(bJson)
{
json_object *poComputedMin = json_object_new_double_with_precision(adfCMinMax[0], 3);
json_object *poComputedMax = json_object_new_double_with_precision(adfCMinMax[1], 3);
json_object_object_add(poBand, "computedMin", poComputedMin);
json_object_object_add(poBand, "computedMax", poComputedMax);
}
else
Concat(osStr, psOptions->bStdoutOutput, " Computed Min/Max=%.3f,%.3f",
adfCMinMax[0], adfCMinMax[1] );
}
}
if(!bJson)
Concat(osStr, psOptions->bStdoutOutput, "\n" );
}
}
double dfMinStat = 0.0;
double dfMaxStat = 0.0;
double dfMean = 0.0;
double dfStdDev = 0.0;
CPLErr eErr = GDALGetRasterStatistics( hBand, psOptions->bApproxStats,
psOptions->bStats,
&dfMinStat, &dfMaxStat,
&dfMean, &dfStdDev );//波段统计
if( eErr == CE_None )
{
if(bJson)
{
json_object *poMinimum = json_object_new_double_with_precision(dfMinStat, 3);
json_object *poMaximum = json_object_new_double_with_precision(dfMaxStat, 3);
json_object *poMean = json_object_new_double_with_precision(dfMean, 3);
json_object *poStdDev = json_object_new_double_with_precision(dfStdDev, 3);
json_object_object_add(poBand, "minimum", poMinimum);
json_object_object_add(poBand, "maximum", poMaximum);
json_object_object_add(poBand, "mean", poMean);
json_object_object_add(poBand, "stdDev", poStdDev);
}
else
Concat(osStr, psOptions->bStdoutOutput, " Minimum=%.3f, Maximum=%.3f, Mean=%.3f, StdDev=%.3f\n",
dfMinStat, dfMaxStat, dfMean, dfStdDev );
}
if( psOptions->bReportHistograms )
{
int nBucketCount;
GUIntBig *panHistogram = NULL;
if(bJson)
eErr = GDALGetDefaultHistogramEx( hBand, &dfMinStat, &dfMaxStat,
&nBucketCount, &panHistogram,
TRUE, GDALDummyProgress,
NULL );//获得默认直方图
else
eErr = GDALGetDefaultHistogramEx( hBand, &dfMinStat, &dfMaxStat,
&nBucketCount, &panHistogram,
TRUE, GDALTermProgress,
NULL );
if( eErr == CE_None )
{
json_object *poHistogram = NULL, *poBuckets = NULL;
if(bJson)
{
json_object *poCount = json_object_new_int(nBucketCount);
json_object *poMin = json_object_new_double(dfMinStat);
json_object *poMax = json_object_new_double(dfMaxStat);
poBuckets = json_object_new_array();
poHistogram = json_object_new_object();
json_object_object_add(poHistogram, "count", poCount);
json_object_object_add(poHistogram, "min", poMin);
json_object_object_add(poHistogram, "max", poMax);
}
else
Concat(osStr, psOptions->bStdoutOutput, " %d buckets from %g to %g:\n ",
nBucketCount, dfMinStat, dfMaxStat );
for( int iBucket = 0; iBucket < nBucketCount; iBucket++ )
{//循环显示条带信息
if(bJson)
{
json_object *poBucket = json_object_new_int64(panHistogram[iBucket]);
json_object_array_add(poBuckets, poBucket);
}
else
Concat(osStr, psOptions->bStdoutOutput, CPL_FRMT_GUIB " ", panHistogram[iBucket] );
}
if(bJson)
{
json_object_object_add(poHistogram, "buckets", poBuckets);
json_object_object_add(poBand, "histogram", poHistogram);
}
else
Concat(osStr, psOptions->bStdoutOutput, "\n" );
CPLFree( panHistogram );
}
}
if ( psOptions->bComputeChecksum)
{
int nBandChecksum = GDALChecksumImage(hBand, 0, 0,
GDALGetRasterXSize(hDataset),
GDALGetRasterYSize(hDataset));//检校波段
if(bJson)
{
json_object *poChecksum = json_object_new_int(nBandChecksum);
json_object_object_add(poBand, "checksum", poChecksum);
}
else
Concat(osStr, psOptions->bStdoutOutput, " Checksum=%d\n", nBandChecksum );
}
int bGotNodata = FALSE;
const double dfNoData = GDALGetRasterNoDataValue( hBand, &bGotNodata );//无数据处像素值
if( bGotNodata )
{
if (CPLIsNan(dfNoData))
{
if(bJson)
{
json_object *poNoDataValue = json_object_new_string("nan");
json_object_object_add(poBand, "noDataValue", poNoDataValue);
}
else
Concat(osStr, psOptions->bStdoutOutput, " NoData Value=nan\n" );
}
else
{
if(bJson)
{
json_object *poNoDataValue = json_object_new_double_with_precision(dfNoData, 18);
json_object_object_add(poBand, "noDataValue", poNoDataValue);
}
else
Concat(osStr, psOptions->bStdoutOutput, " NoData Value=%.18g\n", dfNoData );
}
}
if( GDALGetOverviewCount(hBand) > 0 )//影像金字塔
{
json_object *poOverviews = NULL;
if(bJson)
poOverviews = json_object_new_array();
else
Concat(osStr, psOptions->bStdoutOutput, " Overviews: " );
for( int iOverview = 0;
iOverview < GDALGetOverviewCount(hBand);//####
iOverview++ )
{
if(!bJson)
if( iOverview != 0 )
Concat(osStr, psOptions->bStdoutOutput, ", " );
GDALRasterBandH hOverview = GDALGetOverview( hBand, iOverview );
if (hOverview != NULL)
{
if(bJson)
{
json_object *poOverviewSize = json_object_new_array();
json_object *poOverviewSizeX = json_object_new_int( GDALGetRasterBandXSize( hOverview) );
json_object *poOverviewSizeY = json_object_new_int( GDALGetRasterBandYSize( hOverview) );
json_object *poOverview = json_object_new_object();
json_object_array_add( poOverviewSize, poOverviewSizeX );
json_object_array_add( poOverviewSize, poOverviewSizeY );
json_object_object_add( poOverview, "size", poOverviewSize );
if(psOptions->bComputeChecksum)
{
int nOverviewChecksum = GDALChecksumImage(hOverview, 0, 0,
GDALGetRasterBandXSize(hOverview),
GDALGetRasterBandYSize(hOverview));
json_object *poOverviewChecksum = json_object_new_int(nOverviewChecksum);
json_object_object_add(poOverview, "checksum", poOverviewChecksum);
}
json_object_array_add(poOverviews, poOverview);
}
else
Concat(osStr, psOptions->bStdoutOutput, "%dx%d",
GDALGetRasterBandXSize( hOverview ),
GDALGetRasterBandYSize( hOverview ) );
const char *pszResampling
= GDALGetMetadataItem( hOverview, "RESAMPLING", "" );//元数据项目
if( pszResampling != NULL && !bJson
&& STARTS_WITH_CI(pszResampling, "AVERAGE_BIT2") )
Concat(osStr, psOptions->bStdoutOutput, "*" );
}
else
if(!bJson)
Concat(osStr, psOptions->bStdoutOutput, "(null)" );
}
if(bJson)
json_object_object_add(poBand, "overviews", poOverviews);
else
Concat(osStr, psOptions->bStdoutOutput, "\n" );
if ( psOptions->bComputeChecksum && !bJson )
{
Concat(osStr, psOptions->bStdoutOutput, " Overviews checksum: " );
for( int iOverview = 0;
iOverview < GDALGetOverviewCount(hBand);
iOverview++ )
{
GDALRasterBandH hOverview;
if( iOverview != 0 )
Concat(osStr, psOptions->bStdoutOutput, ", " );
hOverview = GDALGetOverview( hBand, iOverview );
if (hOverview)
{
Concat(osStr, psOptions->bStdoutOutput, "%d",
GDALChecksumImage(hOverview, 0, 0,
GDALGetRasterBandXSize(hOverview),
GDALGetRasterBandYSize(hOverview)));
}
else
{
Concat(osStr, psOptions->bStdoutOutput, "(null)" );
}
}
Concat(osStr, psOptions->bStdoutOutput, "\n" );
}
}
if( GDALHasArbitraryOverviews( hBand ) && !bJson )//判断是否存在预览
{
Concat(osStr, psOptions->bStdoutOutput, " Overviews: arbitrary\n" );
}
const int nMaskFlags = GDALGetMaskFlags( hBand );//获取掩膜标识
if( (nMaskFlags & (GMF_NODATA|GMF_ALL_VALID)) == 0 )
{
GDALRasterBandH hMaskBand = GDALGetMaskBand(hBand) ;//获取掩膜
json_object *poMask = NULL, *poFlags = NULL, *poMaskOverviews = NULL;
if(bJson)
{
poMask = json_object_new_object();
poFlags = json_object_new_array();
}
else
Concat(osStr, psOptions->bStdoutOutput, " Mask Flags: " );
if( nMaskFlags & GMF_PER_DATASET )
{
if(bJson)
{
json_object *poFlag = json_object_new_string( "PER_DATASET" );
json_object_array_add( poFlags, poFlag );
}
else
Concat(osStr, psOptions->bStdoutOutput, "PER_DATASET " );
}
if( nMaskFlags & GMF_ALPHA )
{
if(bJson)
{
json_object *poFlag = json_object_new_string( "ALPHA" );
json_object_array_add( poFlags, poFlag );
}
else
Concat(osStr, psOptions->bStdoutOutput, "ALPHA " );
}
if( nMaskFlags & GMF_NODATA )
{
if(bJson)
{
json_object *poFlag = json_object_new_string( "NODATA" );
json_object_array_add( poFlags, poFlag );
}
else
Concat(osStr, psOptions->bStdoutOutput, "NODATA " );
}
if( nMaskFlags & GMF_ALL_VALID )
{
if(bJson)
{
json_object *poFlag = json_object_new_string( "ALL_VALID" );
json_object_array_add( poFlags, poFlag );
}
else
Concat(osStr, psOptions->bStdoutOutput, "ALL_VALID " );
}
if(bJson)
json_object_object_add( poMask, "flags", poFlags );
else
Concat(osStr, psOptions->bStdoutOutput, "\n" );
if(bJson)
poMaskOverviews = json_object_new_array();
if( hMaskBand != NULL &&
GDALGetOverviewCount(hMaskBand) > 0 )
{//获取掩膜预览
if(!bJson)
Concat(osStr, psOptions->bStdoutOutput, " Overviews of mask band: " );
for( int iOverview = 0;
iOverview < GDALGetOverviewCount(hMaskBand);
iOverview++ )
{
GDALRasterBandH hOverview;
json_object *poMaskOverview = NULL;
json_object *poMaskOverviewSize = NULL;
if(bJson)
{
poMaskOverview = json_object_new_object();
poMaskOverviewSize = json_object_new_array();
}
else
{
if( iOverview != 0 )
Concat(osStr, psOptions->bStdoutOutput, ", " );
}
hOverview = GDALGetOverview( hMaskBand, iOverview );
if(bJson)
{
json_object *poMaskOverviewSizeX =
json_object_new_int(GDALGetRasterBandXSize(hOverview));
json_object *poMaskOverviewSizeY =
json_object_new_int(GDALGetRasterBandYSize(hOverview));
json_object_array_add(poMaskOverviewSize, poMaskOverviewSizeX);
json_object_array_add(poMaskOverviewSize, poMaskOverviewSizeY);
json_object_object_add(poMaskOverview, "size", poMaskOverviewSize);
json_object_array_add(poMaskOverviews, poMaskOverview);
}
else
Concat( osStr, psOptions->bStdoutOutput, "%dx%d",
GDALGetRasterBandXSize( hOverview ),
GDALGetRasterBandYSize( hOverview ) );
}
if(!bJson)
Concat(osStr, psOptions->bStdoutOutput, "\n" );
}
if(bJson)
{
json_object_object_add(poMask, "overviews", poMaskOverviews);
json_object_object_add(poBand, "mask", poMask);
}
}
if( strlen(GDALGetRasterUnitType(hBand)) > 0 )
{
if(bJson)
{
json_object *poUnit = json_object_new_string(GDALGetRasterUnitType(hBand));
json_object_object_add(poBand, "unit", poUnit);
}
else
Concat(osStr, psOptions->bStdoutOutput, " Unit Type: %s\n", GDALGetRasterUnitType(hBand) );//获取栅格单元类型
}
if( GDALGetRasterCategoryNames(hBand) != NULL )
{//获取栅格种类名
char **papszCategories = GDALGetRasterCategoryNames(hBand);
json_object *poCategories = NULL;
if(bJson)
poCategories = json_object_new_array();
else
Concat(osStr, psOptions->bStdoutOutput, " Categories:\n" );
for( int i = 0; papszCategories[i] != NULL; i++ )
{
if(bJson)
{
json_object *poCategoryName = json_object_new_string(papszCategories[i]);
json_object_array_add(poCategories, poCategoryName);
}
else
Concat(osStr, psOptions->bStdoutOutput, " %3d: %s\n", i, papszCategories[i] );
}
if(bJson)
json_object_object_add(poBand, "categories", poCategories);
}
int bSuccess = FALSE;
if( GDALGetRasterScale( hBand, &bSuccess ) != 1.0
|| GDALGetRasterOffset( hBand, &bSuccess ) != 0.0 )//获取栅格比例尺和偏移量
{
if(bJson)
{
json_object *poOffset = json_object_new_double_with_precision(
GDALGetRasterOffset(hBand, &bSuccess), 15);
json_object *poScale = json_object_new_double_with_precision(
GDALGetRasterScale(hBand, &bSuccess), 15);
json_object_object_add(poBand, "offset", poOffset);
json_object_object_add(poBand, "scale", poScale);
}
else
Concat(osStr, psOptions->bStdoutOutput, " Offset: %.15g, Scale:%.15g\n",
GDALGetRasterOffset( hBand, &bSuccess ),
GDALGetRasterScale( hBand, &bSuccess ) );
}
GDALInfoReportMetadata( psOptions, hBand, true, bJson, poBandMetadata, osStr );//报告波段元数据
if(bJson)
{
if (psOptions->bShowMetadata)
json_object_object_add( poBand, "metadata", poBandMetadata );
else
json_object_put(poBandMetadata);
}
GDALColorTableH hTable;
if( GDALGetRasterColorInterpretation(hBand) == GCI_PaletteIndex
&& (hTable = GDALGetRasterColorTable( hBand )) != NULL )//获得颜色索引及色彩表
{
if(!bJson)
Concat( osStr, psOptions->bStdoutOutput,
" Color Table (%s with %d entries)\n",
GDALGetPaletteInterpretationName(
GDALGetPaletteInterpretation( hTable )),
GDALGetColorEntryCount( hTable ) );
if (psOptions->bShowColorTable)
{
json_object *poEntries = NULL;
if(bJson)
{
json_object *poPalette = json_object_new_string(GDALGetPaletteInterpretationName(
GDALGetPaletteInterpretation(hTable)));
json_object *poCount = json_object_new_int(GDALGetColorEntryCount(hTable));
json_object *poColorTable = json_object_new_object();
json_object_object_add(poColorTable, "palette", poPalette);
json_object_object_add(poColorTable, "count", poCount);
poEntries = json_object_new_array();
json_object_object_add(poColorTable, "entries", poEntries);
json_object_object_add(poBand, "colorTable", poColorTable);
}
for( int i = 0; i < GDALGetColorEntryCount( hTable ); i++ )//获取颜色记录
{
GDALColorEntry sEntry;
GDALGetColorEntryAsRGB( hTable, i, &sEntry );
if(bJson)
{
json_object *poEntry = json_object_new_array();
json_object *poC1 = json_object_new_int(sEntry.c1);
json_object *poC2 = json_object_new_int(sEntry.c2);
json_object *poC3 = json_object_new_int(sEntry.c3);
json_object *poC4 = json_object_new_int(sEntry.c4);
json_object_array_add(poEntry, poC1);
json_object_array_add(poEntry, poC2);
json_object_array_add(poEntry, poC3);
json_object_array_add(poEntry, poC4);
json_object_array_add(poEntries, poEntry);
}
else
Concat(osStr, psOptions->bStdoutOutput, " %3d: %d,%d,%d,%d\n",
i,
sEntry.c1,
sEntry.c2,
sEntry.c3,
sEntry.c4 );
}
}
}
if( psOptions->bShowRAT && GDALGetDefaultRAT( hBand ) != NULL )
{
GDALRasterAttributeTableH hRAT = GDALGetDefaultRAT( hBand );//获取栅格属性表
if(bJson)
{
json_object *poRAT = (json_object*) GDALRATSerializeJSON( hRAT );
json_object_object_add( poJsonObject, "rat", poRAT );
}
else
{//获取属性表并转化为xml树状信息
CPLXMLNode *psTree = ((GDALRasterAttributeTable *) hRAT)->Serialize();
char *pszXMLText = CPLSerializeXMLTree( psTree );
CPLDestroyXMLNode( psTree );
Concat(osStr, psOptions->bStdoutOutput, "%s\n", pszXMLText );
CPLFree( pszXMLText );
}
}
if(bJson)
json_object_array_add(poBands, poBand);
}
if(bJson)
{
json_object_object_add(poJsonObject, "bands", poBands);
Concat(osStr, psOptions->bStdoutOutput, "%s", json_object_to_json_string_ext(poJsonObject, JSON_C_TO_STRING_PRETTY));
json_object_put(poJsonObject);
}
if( psOptionsToFree != NULL )
GDALInfoOptionsFree(psOptionsToFree);
return VSI_STRDUP_VERBOSE(osStr);
}
根据函数名称,我们基本能够推断出函数的作用,从获取关联文件到栅格属性表等等。研究本源码文件更多地是向我们展示了GDAL库设计者们对于库函数的使用范本。