Spatial Functions

Aggregation performed spatially across the study area, producing a single value.

Avg_S

• Syntax: Avg_S(grid) returns the mean of all cell values for each passed grid.
• Example:

/*Calculate the global hourly mean land surface temperature(TSURF) for 10/2010.*/
SELECT time, Avg_S(grid) FROM MST1NXMLD 
WHERE variable = "TSURF" AND year = 2010 AND month=10 ORDER BY time

Max_S

• Syntax: Max_S(grid) returns the maxima of all cell values for each passed grid.
• Example:

/*Caculate the maximum monthly liquid water convective precipitation(PRECCU) in 1998.*/	
SELECT month, Max_S(grid) FROM MATMNXINT 
WHERE variable = "PRECCU" AND year = 1998 ORDER BY month

Min_S

• Syntax: Min_S(grid) returns the minima of all cell values for each passed grid.
• Example:

/*Find the lowest land surface temperature at 6PM(UTC) for each day in July 2000.*/	
SELECT day, Min_S(grid) FROM MST1NXMLD 
WHERE variable = "TSURF" AND year = 2000 AND month=7 AND hour = 18 ORDER BY day

Sum_S

• Syntax: Sum_S(grid) returns the sum of all cell values for each passed grid.
• Example:

SELECT Sum_S(grid) FROM MATMNXINT
WHERE variable = "PRECCU" AND year = 1980 AND month = 9

Count_S

• Syntax: Count_S(grid) returns the number of cells for each passed grid.
• Example:

SELECT Count_S(grid) FROM MST1NXMLD 
WHERE variable = "TSURF" AND time = 2010100104

Corr_S

• Syntax: Corr_S(grid1,grid2) returns a correlation coefficient value(Pearson's r) between the cell values of grid1 and grid2.
• Example: