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Merge pull request #6877 from rouault/gdal_get_pixel_value
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SQLITE/GPKG: add a gdal_get_pixel_value() SQL function.
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@rouault
rouault committed Dec 10, 2022
2 parents 4ca7b7e + 837bb28 commit b2f5982
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Showing 10 changed files with 756 additions and 99 deletions.
112 changes: 112 additions & 0 deletions autotest/gdrivers/gpkg.py
View file
Expand Up @@ -4216,6 +4216,118 @@ def test_gpkg_byte_nodata_value(band_count):
gdal.Unlink(filename)


###############################################################################
# Test gdal_get_layer_pixel_value() function


def test_gpkg_sql_gdal_get_layer_pixel_value():

filename = "/vsimem/test_ogr_gpkg_sql_gdal_get_layer_pixel_value.gpkg"
src_ds = gdal.Open("data/byte.tif")
gdal.GetDriverByName("GPKG").CreateCopy(
filename, src_ds, options=["RASTER_TABLE=byte"]
)
src_ds = gdal.Open("data/float32.tif")
gdal.GetDriverByName("GPKG").CreateCopy(
filename, src_ds, options=["APPEND_SUBDATASET=YES"]
)

ds = gdal.OpenEx(filename)
sql_lyr = ds.ExecuteSQL(
"select gdal_get_layer_pixel_value('byte', 1, 'georef', 440780, 3751080)"
)
f = sql_lyr.GetNextFeature()
ds.ReleaseResultSet(sql_lyr)
assert f[0] == 156

sql_lyr = ds.ExecuteSQL(
"select gdal_get_layer_pixel_value('byte', 1, 'pixel', 1, 4)"
)
f = sql_lyr.GetNextFeature()
ds.ReleaseResultSet(sql_lyr)
assert f[0] == 156

sql_lyr = ds.ExecuteSQL(
"select gdal_get_layer_pixel_value('float32', 1, 'pixel', 0, 1)"
)
f = sql_lyr.GetNextFeature()
ds.ReleaseResultSet(sql_lyr)
assert f[0] == 115.0

# Invalid column
sql_lyr = ds.ExecuteSQL(
"select gdal_get_layer_pixel_value('byte', 1, 'pixel', -1, 0)"
)
f = sql_lyr.GetNextFeature()
ds.ReleaseResultSet(sql_lyr)
assert f[0] is None

# NULL as 1st arg
with gdaltest.error_handler():
sql_lyr = ds.ExecuteSQL(
"select gdal_get_layer_pixel_value(NULL, 1, 'pixel', 0, 0)"
)
f = sql_lyr.GetNextFeature()
ds.ReleaseResultSet(sql_lyr)
assert f[0] is None

# NULL as 2nd arg
with gdaltest.error_handler():
sql_lyr = ds.ExecuteSQL(
"select gdal_get_layer_pixel_value('byte', NULL, 'pixel', 0, 0)"
)
f = sql_lyr.GetNextFeature()
ds.ReleaseResultSet(sql_lyr)
assert f[0] is None

# NULL as 3rd arg
with gdaltest.error_handler():
sql_lyr = ds.ExecuteSQL(
"select gdal_get_layer_pixel_value('byte', 1, NULL, 0, 0)"
)
f = sql_lyr.GetNextFeature()
ds.ReleaseResultSet(sql_lyr)
assert f[0] is None

# NULL as 4th arg
with gdaltest.error_handler():
sql_lyr = ds.ExecuteSQL(
"select gdal_get_layer_pixel_value('byte', 1, 'pixel', NULL, 0)"
)
f = sql_lyr.GetNextFeature()
ds.ReleaseResultSet(sql_lyr)
assert f[0] is None

# NULL as 5th arg
with gdaltest.error_handler():
sql_lyr = ds.ExecuteSQL(
"select gdal_get_layer_pixel_value('byte', 1, 'pixel', 0, NULL)"
)
f = sql_lyr.GetNextFeature()
ds.ReleaseResultSet(sql_lyr)
assert f[0] is None

# Invalid band number
with gdaltest.error_handler():
sql_lyr = ds.ExecuteSQL(
"select gdal_get_layer_pixel_value('byte', 0, 'pixel', 0, 0)"
)
f = sql_lyr.GetNextFeature()
ds.ReleaseResultSet(sql_lyr)
assert f[0] is None

# Invalid value for 3rd argument
with gdaltest.error_handler():
sql_lyr = ds.ExecuteSQL(
"select gdal_get_layer_pixel_value('byte', 1, 'invalid', 0, 0)"
)
f = sql_lyr.GetNextFeature()
ds.ReleaseResultSet(sql_lyr)
assert f[0] is None

gdal.Unlink(filename)


###############################################################################
#

Expand Down
124 changes: 124 additions & 0 deletions autotest/ogr/ogr_gpkg.py
View file
Expand Up @@ -8055,3 +8055,127 @@ def test_ogr_gpkg_read_generated_column():
ds = None

gdal.Unlink(filename)


###############################################################################
# Test gdal_get_pixel_value() function


def test_ogr_gpkg_sql_gdal_get_pixel_value():

filename = "/vsimem/test_ogr_gpkg_sql_gdal_get_pixel_value.gpkg"
ds = ogr.GetDriverByName("GPKG").CreateDataSource(filename)

with gdaltest.config_option("OGR_SQLITE_ALLOW_EXTERNAL_ACCESS", "YES"):
sql_lyr = ds.ExecuteSQL(
"select gdal_get_pixel_value('../gcore/data/byte.tif', 1, 'georef', 440780, 3751080)"
)
f = sql_lyr.GetNextFeature()
ds.ReleaseResultSet(sql_lyr)
assert f[0] == 156

with gdaltest.config_option("OGR_SQLITE_ALLOW_EXTERNAL_ACCESS", "YES"):
sql_lyr = ds.ExecuteSQL(
"select gdal_get_pixel_value('../gcore/data/byte.tif', 1, 'pixel', 1, 4)"
)
f = sql_lyr.GetNextFeature()
ds.ReleaseResultSet(sql_lyr)
assert f[0] == 156

with gdaltest.config_option("OGR_SQLITE_ALLOW_EXTERNAL_ACCESS", "YES"):
sql_lyr = ds.ExecuteSQL(
"select gdal_get_pixel_value('../gcore/data/float64.tif', 1, 'pixel', 0, 1)"
)
f = sql_lyr.GetNextFeature()
ds.ReleaseResultSet(sql_lyr)
assert f[0] == 115.0

# Invalid column
with gdaltest.config_option("OGR_SQLITE_ALLOW_EXTERNAL_ACCESS", "YES"):
sql_lyr = ds.ExecuteSQL(
"select gdal_get_pixel_value('../gcore/data/byte.tif', 1, 'pixel', -1, 0)"
)
f = sql_lyr.GetNextFeature()
ds.ReleaseResultSet(sql_lyr)
assert f[0] is None

# Missing OGR_SQLITE_ALLOW_EXTERNAL_ACCESS
with gdaltest.error_handler():
sql_lyr = ds.ExecuteSQL(
"select gdal_get_pixel_value('../gcore/data/byte.tif', 1, 'georef', 440720, 3751320)"
)
f = sql_lyr.GetNextFeature()
ds.ReleaseResultSet(sql_lyr)
assert f[0] is None

# NULL as 1st arg
with gdaltest.error_handler():
with gdaltest.config_option("OGR_SQLITE_ALLOW_EXTERNAL_ACCESS", "YES"):
sql_lyr = ds.ExecuteSQL(
"select gdal_get_pixel_value(NULL, 1, 'pixel', 0, 0)"
)
f = sql_lyr.GetNextFeature()
ds.ReleaseResultSet(sql_lyr)
assert f[0] is None

# NULL as 2nd arg
with gdaltest.error_handler():
with gdaltest.config_option("OGR_SQLITE_ALLOW_EXTERNAL_ACCESS", "YES"):
sql_lyr = ds.ExecuteSQL(
"select gdal_get_pixel_value('../gcore/data/byte.tif', NULL, 'pixel', 0, 0)"
)
f = sql_lyr.GetNextFeature()
ds.ReleaseResultSet(sql_lyr)
assert f[0] is None

# NULL as 3rd arg
with gdaltest.error_handler():
with gdaltest.config_option("OGR_SQLITE_ALLOW_EXTERNAL_ACCESS", "YES"):
sql_lyr = ds.ExecuteSQL(
"select gdal_get_pixel_value('../gcore/data/byte.tif', 1, NULL, 0, 0)"
)
f = sql_lyr.GetNextFeature()
ds.ReleaseResultSet(sql_lyr)
assert f[0] is None

# NULL as 4th arg
with gdaltest.error_handler():
with gdaltest.config_option("OGR_SQLITE_ALLOW_EXTERNAL_ACCESS", "YES"):
sql_lyr = ds.ExecuteSQL(
"select gdal_get_pixel_value('../gcore/data/byte.tif', 1, 'pixel', NULL, 0)"
)
f = sql_lyr.GetNextFeature()
ds.ReleaseResultSet(sql_lyr)
assert f[0] is None

# NULL as 5th arg
with gdaltest.error_handler():
with gdaltest.config_option("OGR_SQLITE_ALLOW_EXTERNAL_ACCESS", "YES"):
sql_lyr = ds.ExecuteSQL(
"select gdal_get_pixel_value('../gcore/data/byte.tif', 1, 'pixel', 0, NULL)"
)
f = sql_lyr.GetNextFeature()
ds.ReleaseResultSet(sql_lyr)
assert f[0] is None

# Invalid band number
with gdaltest.error_handler():
with gdaltest.config_option("OGR_SQLITE_ALLOW_EXTERNAL_ACCESS", "YES"):
sql_lyr = ds.ExecuteSQL(
"select gdal_get_pixel_value('../gcore/data/byte.tif', 0, 'pixel', 0, 0)"
)
f = sql_lyr.GetNextFeature()
ds.ReleaseResultSet(sql_lyr)
assert f[0] is None

# Invalid value for 3rd argument
with gdaltest.error_handler():
with gdaltest.config_option("OGR_SQLITE_ALLOW_EXTERNAL_ACCESS", "YES"):
sql_lyr = ds.ExecuteSQL(
"select gdal_get_pixel_value('../gcore/data/byte.tif', 1, 'invalid', 0, 0)"
)
f = sql_lyr.GetNextFeature()
ds.ReleaseResultSet(sql_lyr)
assert f[0] is None

gdal.Unlink(filename)
27 changes: 27 additions & 0 deletions doc/source/drivers/raster/gpkg.rst
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Expand Up @@ -610,6 +610,33 @@ Examples

gdalinfo my.gpkg -oo TABLE=a_table

.. _raster.gpkg.raster:

Raster SQL functions
~~~~~~~~~~~~~~~~~~~~

The raster SQL functions mentioned at :ref:`sql_sqlite_dialect_raster_functions`
are also available.

The ``gdal_get_layer_pixel_value()`` function (added in GDAL 3.7), variant of the
generic ``gdal_get_pixel_value()``, can be used to extract the value of a pixel
in a raster layer of the current dataset.

It takes 5 arguments:

* a string with the layer/table name
* a band number (numbering starting at 1)
* a string being "georef" to indicate that subsequent values will be georeferenced
coordinates, or "pixel" to indicate that subsequent values will be in column, line
pixel space
* georeferenced X value or column number
* georeferenced Y value or line number

.. code-block::
SELECT gdal_get_layer_pixel_value('my_raster_table', 1, 'georef', 440720, 3751320)
SELECT gdal_get_layer_pixel_value('my_raster_table', 1, 'pixel', 0, 0)
See Also
--------

Expand Down
3 changes: 3 additions & 0 deletions doc/source/drivers/vector/gpkg.rst
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Expand Up @@ -124,6 +124,9 @@ Spatialite, are also available :
in gpkg_spatial_ref_sys, starting with GDAL 3.2, it will be interpreted as
a EPSG code.

The raster SQL functions mentioned at :ref:`raster.gpkg.raster`
are also available.

Link with Spatialite
~~~~~~~~~~~~~~~~~~~~

Expand Down
25 changes: 25 additions & 0 deletions doc/source/user/sql_sqlite_dialect.rst
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Expand Up @@ -257,6 +257,31 @@ a value associate to a key from a HSTORE string, formatted like "key=>value,othe
SELECT hstore_get_value('a => b, "key with space"=> "value with space"', 'key with space') --> 'value with space'
.. _sql_sqlite_dialect_raster_functions:

Raster related functions
++++++++++++++++++++++++

The ``gdal_get_pixel_value()`` function (added in GDAL 3.7) can be used to extract the value
of a pixel in a GDAL dataset. It requires the configuration option OGR_SQLITE_ALLOW_EXTERNAL_ACCESS
to be set to YES (for security reasons).

It takes 5 arguments:

* a string with the dataset name
* a band number (numbering starting at 1)
* a string being "georef" to indicate that subsequent values will be georeferenced
coordinates, or "pixel" to indicate that subsequent values will be in column, line
pixel space
* georeferenced X value or column number
* georeferenced Y value or line number

.. code-block::
SELECT gdal_get_pixel_value('../gcore/data/byte.tif', 1, 'georef', 440720, 3751320)
SELECT gdal_get_pixel_value('../gcore/data/byte.tif', 1, 'pixel', 0, 0)
OGR geocoding functions
+++++++++++++++++++++++

Expand Down
8 changes: 8 additions & 0 deletions ogr/ogrsf_frmts/gpkg/ogr_geopackage.h
View file
Expand Up @@ -122,6 +122,7 @@ class GDALGeoPackageDataset final : public OGRSQLiteBaseDataSource, public GDALG
int argc,
sqlite3_value** argv);

void *m_pSQLFunctionData = nullptr;
GUInt32 m_nApplicationId = GPKG_APPLICATION_ID;
GUInt32 m_nUserVersion = GPKG_1_2_VERSION;
OGRGeoPackageTableLayer** m_papoLayers = nullptr;
Expand Down Expand Up @@ -272,6 +273,11 @@ class GDALGeoPackageDataset final : public OGRSQLiteBaseDataSource, public GDALG
bool m_bIsGeometryTypeAggregateInterrupted = false;
std::string m_osGeometryTypeAggregateResult{};

// Used by GDALGeoPackageDataset::GetRasterLayerDataset()
std::map< std::string, std::unique_ptr<GDALDataset> > m_oCachedRasterDS{};

void CloseDB();

CPL_DISALLOW_COPY_ASSIGN(GDALGeoPackageDataset)

public:
Expand Down Expand Up @@ -387,6 +393,8 @@ class GDALGeoPackageDataset final : public OGRSQLiteBaseDataSource, public GDALG
void SetGeometryTypeAggregateResult(const std::string& s) { m_osGeometryTypeAggregateResult = s; }
const std::string& GetGeometryTypeAggregateResult() const { return m_osGeometryTypeAggregateResult; }

GDALDataset* GetRasterLayerDataset(const char* pszLayerName);

protected:

virtual CPLErr IRasterIO( GDALRWFlag, int, int, int, int,
Expand Down

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