GeoRaster NODATA question

Simon Greener

I have a single (band) GeoRaster object in a table.

The raster is cookie cut by a polygon to produce statistics using SDO_GEOR.generateStatistics.

Some of the pixels in the raster have -Infinity values. When these are within the polygon generateStatistics fails to produce valid values like MIN. I tried to set the -infinity value as the NODATA value:

DECLARE

 gr sdo_georaster;

BEGIN

 SELECT raster INTO gr FROM carbon WHERE id=1 FOR UPDATE;

 SDO_GEOR.addNODATA(gr, 0, sdo_range_array(sdo_range(-1*binary_double_infinity,0)));

 UPDATE carbon SET raster=gr WHERE id=1;

 COMMIT;

END;

/

But after doing so the following nodata query returns 0 and not -Infinity.

SELECT SDO_GEOR.getNODATA(raster, 0) NODATA FROM carbon WHERE id=1;

NODATA(LB, UB) 

-------------------------------------------------

SDO_RANGE_ARRAY(SDO_RANGE(0, NULL))

The generateStatistics query looks like this:

SELECT rownum as measure, 

        t.column_value

     FROM carbon a,

        (select geom from property where id = 524) b,

        SDO_GEOR.generateStatistics(

          georaster   => a.raster,

          pyramidLevel  => 0,

          samplingFactor => 'samplingFactor=1',

          samplingWindow => SDO_GEOM.SDO_INTERSECTION(b.geom,a.raster.spatialExtent,0.05),

          bandNumbers  => '0',

          nodata     => 'TRUE',

          polygonClip  => 'TRUE', 

          parallelParam => NULL

        ) t

Resulting in:

  MEASURE Result Sequence

---------- ---------------

     1 -Infinity    

     2   452.327681

     3 -Infinity    

     4 -Infinity    

     5 -Infinity    

(Doesn't produce all 7 rows for some reason.)

Can anyone help?

Fechen-Oracle

Currently GeoRaster doesn't support NODATA value as binary_double_infinity. Will it be possible to use an actual value as NODATA in the raster?

Fechen-Oracle

From your script above, it seems that all of your normal pixel values are above 0. If so, you can use the following script to change the -infinity value to another value <new value>:

declare

gr sdo_georaster;

begin

select raster into gr from carbon where id=1;

sdo_geor_ra.rasterUpdate(gr, 0, SDO_STRING2_ARRAY('{0}<0'), SDO_STRING2_ARRAYSET(SDO_STRING2_ARRAY('<new value>')));

commit;

end;

/

This script changes any cell value less than 0 on band 0 to a new value.

Fechen-Oracle

Currently GeoRaster doesn't support NODATA value as binary_double_infinity. Will it be possible to use an actual value as NODATA in the raster?

Simon Greener

How can I recode the currently loaded GeoRaster with the -Infinite values?

Fechen-Oracle

From your script above, it seems that all of your normal pixel values are above 0. If so, you can use the following script to change the -infinity value to another value <new value>:

declare

gr sdo_georaster;

begin

select raster into gr from carbon where id=1;

sdo_geor_ra.rasterUpdate(gr, 0, SDO_STRING2_ARRAY('{0}<0'), SDO_STRING2_ARRAYSET(SDO_STRING2_ARRAY('<new value>')));

commit;

end;

/

This script changes any cell value less than 0 on band 0 to a new value.