Changes between Version 142 and Version 143 of WKTRaster/SpecificationWorking03

Show
Ignore:
Timestamp:
07/11/11 13:48:15 (23 months ago)
Author:
pracine
Comment:

--

Legend:

Unmodified
Added
Removed
Modified

  • WKTRaster/SpecificationWorking03

    v142 v143  
    339339 * Here are some commonly used predefined expressions and how they materialize as the four (4) "p_", "t_" and "f_" expressions passed to ST_Mapalgebra(rast1, rast2): 
    340340 
    341    - LAST: 'rast2', 'rast2', 'rast1', NULL 
    342  
    343    - FIRST: 'rast1', 'rast2', 'rast1', NULL 
    344  
    345    - MIN: 'LEAST(rast1, rast2)', 'rast2', 'rast1', NULL 
    346  
    347    - MAX: 'GREATEST(rast1, rast2)', 'rast2', 'rast1', NULL 
    348  
    349    - COUNT: 'rast1 + 1', '1', 'rast1', '0' 
    350  
    351    - SUM: 'rast1 + rast2', 'rast2', 'rast1', NULL 
     341  - LAST: 'rast2', 'rast2', 'rast1', NULL 
     342 
     343  -FIRST: 'rast1', 'rast2', 'rast1', NULL 
     344 
     345  -MIN: 'LEAST(rast1, rast2)', 'rast2', 'rast1', NULL 
     346 
     347  -MAX: 'GREATEST(rast1, rast2)', 'rast2', 'rast1', NULL 
     348 
     349  -COUNT: 'rast1 + 1', '1', 'rast1', '0' 
     350 
     351  -SUM: 'rast1 + rast2', 'rast2', 'rast1', NULL 
    352352    
    353    - RANGE:  
    354     - p_expressions = 'LEAST(rast1, rast2)', 'rast2', 'rast1', NULL 
    355     - t_expressions = 'GREATEST(rast1, rast2)', 'rast2', 'rast1', NULL 
    356     - f_expressions = 'rast1 - rast2', NULL, NULL, NULL 
     353  -RANGE:[[BR]] 
     354    -p_expressions = 'LEAST(rast1, rast2)', 'rast2', 'rast1', NULL[[BR]] 
     355    -t_expressions = 'GREATEST(rast1, rast2)', 'rast2', 'rast1', NULL[[BR]] 
     356    -f_expressions = 'rast1 - rast2', NULL, NULL, NULL 
    357357     
    358    - MEAN:  
    359     - p_expressions = 'rast1 + rast2', 'rast2', 'rast1', NULL  //sum 
    360     - t_expressions = 'rast1 + 1', '1', 'rast1', '0'   //count 
    361     - f_expressions = 'CASE WHEN rast2 > 0 THEN rast1 / rast2::float8 ELSE NULL END', NULL, NULL, NULL  //sum/count  
     358  -MEAN:[[BR]] 
     359   -p_expressions = 'rast1 + rast2', 'rast2', 'rast1', NULL  //sum[[BR]] 
     360   -t_expressions = 'rast1 + 1', '1', 'rast1', '0'   //count[[BR]] 
     361   -f_expressions = 'CASE WHEN rast2 > 0 THEN rast1 / rast2::float8 ELSE NULL END', NULL, NULL, NULL  //sum/count  
    362362     
    363    - STANDARD_DEVIATION: NOT POSSIBLE, nead two passes. See how ST_SummaryStats() does it... 
     363  -STANDARD_DEVIATION: NOT POSSIBLE, nead two passes. See how ST_SummaryStats() does it... 
    364364    
    365    - MAX_LENGTH, MAX_AREA or MAX_ANYTHING (require MapAlgebra being able to reference other bans than 1): 
    366     - p_expressions = 'CASE WHEN rast1[2] > rast2[t] THEN rast1[1] ELSE rast2[1] END', 'rast2[1]', 'rast1[1]', NULL 
    367     - t_expressions = 'CASE WHEN rast1[2] > rast2[2] THEN rast1[2] ELSE rast2[2] END', 'rast2[2]', 'rast1[2]', NULL 
    368     - f_expressions = 'rast1', NULL, NULL, NULL 
    369  
     365  -MAX_LENGTH, MAX_AREA or MAX_ANYTHING (require MapAlgebra being able to reference other bans than 1):[[BR]] 
     366   -p_expressions = 'CASE WHEN rast1[2] > rast2[t] THEN rast1[1] ELSE rast2[1] END', 'rast2[1]', 'rast1[1]', NULL[[BR]] 
     367   -t_expressions = 'CASE WHEN rast1[2] > rast2[2] THEN rast1[2] ELSE rast2[2] END', 'rast2[2]', 'rast1[2]', NULL[[BR]] 
     368   -f_expressions = 'rast1', NULL, NULL, NULL 
    370369 
    371370 * A PL/pgSQL prototype of ST_Union exist in script/plpgsql/st_union.sql.