How to extract row number of geoRaster as number ?

Question

Hi all,
I need to get the row (or similarly column and band) number of a georaster as number. Some approach that i have explored :
(a)
Using SDO_GEOR.getSpatialDimSizes, which return an sdo_Number_array. For example SDO_NUMBER_ARRAY(211, 725) means 211 rows by 725 columns.
But then how to get the 211 (or 725) as a number ? Any command for extracting the value ? substring clearly helpless.
(b)
Using metadata extract in PL/SQL. An example is
create or replace function dimRaster
(gr sdo_georaster)
return number as
total_dim number;
begin
total_dim := gr.metadata.extract('/georasterMetadata/rasterInfo/totalDimensions/text()',
'xmlns=http://xmlns.oracle.com/spatial/georaster').getNumberVal();
dbms_output.put_line('Total dimesnion'||CHR(9)||': '||total_dim);
return null;
end;-----------------
The above works fine. It extracts the value in rasterInfo>totalDimensions as NUMBER. But the following isn't working:
dim_row number;
dim_row_Str := gr.metadata.extract('/georasterMetadata/rasterInfo/dimensionSize type="ROW"/size/text()',
'xmlns=http://xmlns.oracle.com/spatial/georaster').getStringVal();
I get the following error message
ORA-31011: XML parsing failed
ORA-19202: Error occurred in XML processing
LPX-00601: Invalid token in: '/georasterMetadata/rasterInfo/dimensionSize type="ROW"/size/text()'
The number that i need to extract is in rasterInfo> dimensionSize type="ROW"> size.
Please advise.
cheers,
=Damon

Answer 1

Here is a function to do it. Since a function can only return one value, I created an object type for it.
If this was going onto my production system, I would validate the metadata before running the procedure on a georaster object.
Hope this helps:
-- gr_dims object holds # rows, # columns, and # bands
create or replace type gr_dims as object (
  r number,
  c number,
  b number);
create or replace function georaster_size (geor sdo_georaster)
return gr_dims deterministic is
rowcols sdo_number_array := new sdo_number_array();
result gr_dims := new gr_dims(null,null,null);
begin
  rowcols.extend(3);
  rowcols  := SDO_GEOR.getSpatialDimSizes(geor);
  result.r := rowcols(1);
  result.c := rowcols(2);
  result.b := SDO_GEOR.getBandDimSize(geor);
  return result;
end;
select georaster_size(georaster) from map_rasters where georid=1;
--GEORASTER_SIZE(GEORASTER)(R, C, B)
--GR_DIMS(5117, 3748, 1)
select g.gr.r, g.gr.c, g.gr.b
from (select georaster_size(georaster) gr from map_rasters where georid=1) g;
--      GR.R       GR.C       GR.B
--      5117       3748          1