Applying a colormap to multiple Georasters

Question

Hi All,
We have 110 years of gridded weather data that we are storing within Oracle Spatial 11g and then publishing this data to the web using MapViewer. I'm making the assumption that it's best to store this data as georasters rather than gridded polygons with attributes, although I'm keen to hear from anyone that has dealt with large gridded datasets and can advise on the best methods.
Going down the georaster track we have created a single table for each category eg, maximum temperature, minimum temperature, rainfall etc. and by using the gdal_translate populated the tables with multiple georasters for each single day. In trying to view the data it's currently grey scale images, but coloured is preferred. There is only one band within these datasets. I have applied a colour map to the georasters by using the following code.
DECLARE
grobj sdo_georaster;
cmobj sdo_geor_colormap;
BEGIN
cmobj := sdo_geor_colormap(sdo_number_array(0,1,5,10,15,25,50,100,150,200,300,400,500),
sdo_number_array(255,253,255,255,170,74,0,0,0,170,255,255,0),
sdo_number_array(255,205,170,255,255,222,255,170,0,85,0,0,0),
sdo_number_array(255,9,0,0,0,0,127,255,255,255,255,127,0),
sdo_number_array(255,255,255,255,255,255,255,255,255,255,255,255,255));
SELECT georaster INTO grobj FROM rainfall_daily WHERE rasterid=1503 FOR UPDATE;
sdo_geor.setColorMap(grobj, 0, cmobj);
UPDATE rainfall_daily SET georaster = grobj WHERE rasterid=1503;
COMMIT;
END;
Unfortunately the colours did not work as I was hoping, the image is still largely greyscale with a slight yellowish shading on very few pixels. Is there a way to colourise a georaster with using these values and ramping between each value and colour? The stored pixel values range from 0 - 500.00 therefore do we need to create a colormap including all values including decimal values to 2 places.
Once the colormap has been applied will MapViewer refer to the colormap for creating the map image as there is no styling available for georaster themes within MapBuilder?
Any help would greatly be appreciated.
Kerryne

Answer 1

Hi Jeffery,
Thank you for your responses. Our dataset is a static grid with only the pixel values changing each day for each attribute. I have loaded each day as a separate georaster entry into the table, but should I be loading the pixel values from each day to a layer within the georaster? So that each year may be one georaster but with 365 layers associated to it. I must admit I got quite confused with your second response. If I create just the one gridded polygon dataset how do you relate this to all the georasters, or do you create one gridded dataset from the georaster and then have an attribute table with the location of the cell/grid as the primary link?
Do you have an example of a large colormap that I could use as an example as I could only find an example of a black or white colormap?
I tried the call for sdo_generateStatistics but this failed with the following output.
DECLARE
gr SDO_GEORASTER;
ret VARCHAR2(256);
window SDO_NUMBER_ARRAY := SDO_NUMBER_ARRAY(112.32,-44.14,156.12,-10.27);
BEGIN
SELECT georaster INTO gr FROM rainfall_daily WHERE rasterid=1503 FOR UPDATE;
SDO_GEOR.setBinFunction(gr,1,sdo_number_array(0,13,0,0,500));
ret:=SDO_GEOR.generateStatistics(gr,2,window,'TRUE','1-1','TRUE');
UPDATE rainfall_daily SET georaster=gr WHERE rasterid=1503;
COMMIT;
END;
Error report:
ORA-13497: Invalid samplingFactor; using string like "samplingFactor=5".
ORA-06512: at "MDSYS.MD", line 1723
ORA-06512: at "MDSYS.MDERR", line 17
ORA-06512: at "MDSYS.SDO_GEOR", line 5381
ORA-06512: at "MDSYS.SDO_GEOR", line 5413
ORA-06512: at line 8
13497. 00000 - "%s"
*Cause:    This is an internal GeoRaster error.
*Action:   Contact Oracle Support Services. You may want to make
sure the GeoRaster object is valid before you do so.
I also tried sdo_geor.validategeoraster and came across some rasters that were true and others that had an error code of 13454.
select sdo_geor.validategeoraster(t.georaster) isvalid
from rainfall_daily t where rasterid=1503 ;
1 13454
So I tried :
select sdo_geor.schemavalidate(t.georaster) isvalid
from rainfall_daily t where rasterid=1503 ;
ORA-31154: invalid XML document
ORA-19202: Error occurred in XML processing
LSX-00204: extra data at end of complex element
ORA-06512: at "SYS.XMLTYPE", line 354
ORA-06512: at "MDSYS.SDO_GEOR", line 3263
31154. 00000 - "invalid XML document"
*Cause:    The XML document is invalid with respect to its XML Schema.
*Action:   Fix the errors identified and try again.
The data had been populated into the database by using the same method as below:
gdal_translate -of georaster $BASENAME.flt geor:db/dbPWD@CLIPART,db.rainfall_daily,georaster\
-co INSERT="VALUES (SEQ_RAINDAY_ID.NEXTVAL,'$DAY-$MONTH2-$YEAR','$VAR',SDO_GEOR.INIT('RAINFALL_DAILY_RDT'))"\
-co "SRID=4283" -co "BLOCKXSIZE=512" -co "BLOCKYSIZE=512" -co "BLOCKBSIZE=3" -co "INTERLEAVE=PIXEL"
So I'm a bit perplexed as to why some would be "true" and others would be erroneous. I'm not sure of what extra data could have been added to the XML schema.
What would you recommend to be the next step to resolve this?
Cheers
Kerryne