Changes between Version 142 and Version 143 of WKTRaster/SpecificationWorking03

Timestamp:

07/11/11 13:48:15 (13 years ago)

Author:

pracine

Comment:

—

WKTRaster/SpecificationWorking03

@@ -339 +339 @@
  * 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):
 
-   - LAST: 'rast2', 'rast2', 'rast1', NULL
-
-   - FIRST: 'rast1', 'rast2', 'rast1', NULL
-
-   - MIN: 'LEAST(rast1, rast2)', 'rast2', 'rast1', NULL
-
-   - MAX: 'GREATEST(rast1, rast2)', 'rast2', 'rast1', NULL
-
-   - COUNT: 'rast1 + 1', '1', 'rast1', '0'
-
-   - SUM: 'rast1 + rast2', 'rast2', 'rast1', NULL
+  - LAST: 'rast2', 'rast2', 'rast1', NULL
+
+  -FIRST: 'rast1', 'rast2', 'rast1', NULL
+
+  -MIN: 'LEAST(rast1, rast2)', 'rast2', 'rast1', NULL
+
+  -MAX: 'GREATEST(rast1, rast2)', 'rast2', 'rast1', NULL
+
+  -COUNT: 'rast1 + 1', '1', 'rast1', '0'
+
+  -SUM: 'rast1 + rast2', 'rast2', 'rast1', NULL
    
-   - RANGE: 
-    - p_expressions = 'LEAST(rast1, rast2)', 'rast2', 'rast1', NULL
-    - t_expressions = 'GREATEST(rast1, rast2)', 'rast2', 'rast1', NULL
-    - f_expressions = 'rast1 - rast2', NULL, NULL, NULL
+  -RANGE:[[BR]]
+    -p_expressions = 'LEAST(rast1, rast2)', 'rast2', 'rast1', NULL[[BR]]
+    -t_expressions = 'GREATEST(rast1, rast2)', 'rast2', 'rast1', NULL[[BR]]
+    -f_expressions = 'rast1 - rast2', NULL, NULL, NULL
     
-   - MEAN: 
-    - p_expressions = 'rast1 + rast2', 'rast2', 'rast1', NULL  //sum
-    - t_expressions = 'rast1 + 1', '1', 'rast1', '0'   //count
-    - f_expressions = 'CASE WHEN rast2 > 0 THEN rast1 / rast2::float8 ELSE NULL END', NULL, NULL, NULL  //sum/count 
+  -MEAN:[[BR]]
+   -p_expressions = 'rast1 + rast2', 'rast2', 'rast1', NULL  //sum[[BR]]
+   -t_expressions = 'rast1 + 1', '1', 'rast1', '0'   //count[[BR]]
+   -f_expressions = 'CASE WHEN rast2 > 0 THEN rast1 / rast2::float8 ELSE NULL END', NULL, NULL, NULL  //sum/count 
     
-   - STANDARD_DEVIATION: NOT POSSIBLE, nead two passes. See how ST_SummaryStats() does it...
+  -STANDARD_DEVIATION: NOT POSSIBLE, nead two passes. See how ST_SummaryStats() does it...
    
-   - MAX_LENGTH, MAX_AREA or MAX_ANYTHING (require MapAlgebra being able to reference other bans than 1):
-    - p_expressions = 'CASE WHEN rast1[2] > rast2[t] THEN rast1[1] ELSE rast2[1] END', 'rast2[1]', 'rast1[1]', NULL
-    - t_expressions = 'CASE WHEN rast1[2] > rast2[2] THEN rast1[2] ELSE rast2[2] END', 'rast2[2]', 'rast1[2]', NULL
-    - f_expressions = 'rast1', NULL, NULL, NULL
-
+  -MAX_LENGTH, MAX_AREA or MAX_ANYTHING (require MapAlgebra being able to reference other bans than 1):[[BR]]
+   -p_expressions = 'CASE WHEN rast1[2] > rast2[t] THEN rast1[1] ELSE rast2[1] END', 'rast2[1]', 'rast1[1]', NULL[[BR]]
+   -t_expressions = 'CASE WHEN rast1[2] > rast2[2] THEN rast1[2] ELSE rast2[2] END', 'rast2[2]', 'rast1[2]', NULL[[BR]]
+   -f_expressions = 'rast1', NULL, NULL, NULL
 
  * A PL/pgSQL prototype of ST_Union exist in script/plpgsql/st_union.sql.