Added manual page and example to t.rast.mapcalc

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@54824 15284696-431f-4ddb-bdfa-cd5b030d7da7

lib/python/temporal/mapcalc.py

@@ -28,7 +28,7 @@ def dataset_mapcalculator(inputs, output, type, expression, base, method,
        selected maps. Temporal operators are available in addition to 
        the r.mapcalc operators:
        
-       Supported operators for relative and absolute time:
+       Supported operators for relative and absolute time are:
        * td() - the time delta of the current interval in days 
          and fractions of days or the unit in case of relative time
        * start_time() - The start time of the interval from the begin of the time 
@@ -47,17 +47,17 @@ def dataset_mapcalculator(inputs, output, type, expression, base, method,
        * start_hour() - The hour of the start time [0 - 23]
        * start_minute() - The minute of the start time [0 - 59]
        * start_second() - The second of the start time [0 - 59]
-       
-       * end_doy() - Day of year (doy) from the start time [1 - 366]
+
+       * end_doy() - Day of year (doy) from the end time [1 - 366]
        * end_dow() - Day of week (dow) from the end time [1 - 7], 
-         end is monday == 1
+         the start of the week is monday == 1
        * end_year() - The year of the end time [0 - 9999]
        * end_month() - The month of the end time [1 - 12]
-       * end_woy() - Week of year (woy) of the end time [1 - 54]
-       * end_day() - Day of month from the start time [1 - 31]
+       * end_week() - Week of year of the end time [1 - 54]
+       * end_day() - Day of month from the end time [1 - 31]
        * end_hour() - The hour of the end time [0 - 23]
        * end_minute() - The minute of the end time [0 - 59]
-       * end_second() - The second of the end time [0 - 59]
+       * end_second() - The minute of the end time [0 - 59]
        
 
        @param input The name of the input space time raster/raster3d dataset
@@ -416,17 +416,17 @@ def _operator_parser(expr, first, current):
        * start_hour() - The hour of the start time [0 - 23]
        * start_minute() - The minute of the start time [0 - 59]
        * start_second() - The second of the start time [0 - 59]
-       
-       * end_doy() - Day of year (doy) from the start time [1 - 366]
+
+       * end_doy() - Day of year (doy) from the end time [1 - 366]
        * end_dow() - Day of week (dow) from the end time [1 - 7], 
-         end is monday == 1
+         the start of the week is monday == 1
        * end_year() - The year of the end time [0 - 9999]
        * end_month() - The month of the end time [1 - 12]
-       * end_woy() - Week of year (woy) of the end time [1 - 54]
-       * end_day() - Day of month from the start time [1 - 31]
+       * end_week() - Week of year of the end time [1 - 54]
+       * end_day() - Day of month from the end time [1 - 31]
        * end_hour() - The hour of the end time [0 - 23]
        * end_minute() - The minute of the end time [0 - 59]
-       * end_second() - The second of the end time [0 - 59]
+       * end_second() - The minute of the end time [0 - 59]
        
        The modified expression is returned.
        
@@ -502,7 +502,7 @@ def _parse_end_operators(expr, is_time_absolute, current):
        Supported operators for absolute time:
        * end_doy() - Day of year (doy) from the end time [1 - 366]
        * end_dow() - Day of week (dow) from the end time [1 - 7], 
-         the end of the week is monday == 1
+         the start of the week is monday == 1
        * end_year() - The year of the end time [0 - 9999]
        * end_month() - The month of the end time [1 - 12]
        * end_week() - Week of year of the end time [1 - 54]
@@ -582,7 +582,7 @@ def _parse_end_operators(expr, is_time_absolute, current):
 
 def _parse_td_operator(expr, is_time_absolute, first, current):
     """Parse the time delta operator td(). This operator
-       represents the size of the current time interval
+       represents the size of the current sample time interval
        in days and fraction of days for absolute time,
        and in relative units in case of relative time.
        
@@ -607,7 +607,7 @@ def _parse_td_operator(expr, is_time_absolute, first, current):
 def _parse_start_time_operator(expr, is_time_absolute, first, current):
     """Parse the start_time() operator. This operator represent 
     the time difference between the start time of the sample space time
-    raster dataset and the start time of the current interval or instance. The time
+    raster dataset and the start time of the current sample interval or instance. The time
     is measured  in days and fraction of days for absolute time,
     and in relative units in case of relative time."""
     if expr.find("start_time()") >= 0:
@@ -628,7 +628,7 @@ def _parse_start_time_operator(expr, is_time_absolute, first, current):
 def _parse_end_time_operator(expr, is_time_absolute, first, current):
     """Parse the end_time() operator. This operator represent 
     the time difference between the start time of the sample space time
-    raster dataset and the start time of the current interval. The time
+    raster dataset and the end time of the current sample interval. The time
     is measured  in days and fraction of days for absolute time,
     and in relative units in case of relative time.
     

temporal/t.rast.mapcalc/example.sh

@@ -0,0 +1,38 @@
+#!/bin/sh
+g.region s=0 n=80 w=0 e=120 b=0 t=50 res=10 res3=10 -p3
+# Lets create the raster maps
+r.mapcalc --o expr="a3 = 3"
+r.mapcalc --o expr="a4 = 4"
+r.mapcalc --o expr="a5 = 5"
+r.mapcalc --o expr="a6 = 6"
+r.mapcalc --o expr="a7 = 7"
+r.mapcalc --o expr="a8 = 8"
+
+r.mapcalc --o expr="b1 = 1"
+r.mapcalc --o expr="b2 = 2"
+r.mapcalc --o expr="b3 = 3"
+r.mapcalc --o expr="b4 = 4"
+r.mapcalc --o expr="b5 = 5"
+r.mapcalc --o expr="b6 = 6"
+r.mapcalc --o expr="b7 = 7"
+r.mapcalc --o expr="b8 = 8"
+r.mapcalc --o expr="b9 = 8"
+r.mapcalc --o expr="b10 = 10"
+r.mapcalc --o expr="b11 = 11"
+r.mapcalc --o expr="b12 = 12"
+
+t.create --o type=strds temporaltype=absolute \
+    output=A title="Dataset A" descr="Dataset A"
+t.create --o type=strds temporaltype=absolute \
+    output=B title="Dataset B" descr="Dataset B"
+t.register --o -i type=rast input=A maps=a3,a4,a5,a6,a7,a8 \
+    start="2001-03-01" increment="1 months"
+t.register --o -i type=rast input=B maps=b1,b2,b3,b4,b5,b6,b7,b8,b9,b10,b11,b12 \
+    start="2001-01-01" increment="1 months"
+
+t.rast.mapcalc --o --v input=A,B output=C base=c method=equal \
+    expr="if(start_month() == 5 || start_month() == 6, (A + B), (A * B))"
+
+t.info type=strds input=C
+t.rast.list -h input=C columns=name,start_time,min,max
+

temporal/t.rast.mapcalc/t.rast.mapcalc.html

@@ -1,11 +1,170 @@
 <h2>DESCRIPTION</h2>
 
-TBD.
+The purpose of <em>t.rast.mapcalc</em> is to perform spatio-temporal <em>mapcalc</em> expressions
+on maps of temporally sampled space time raster datasets (STRDS). Spatial and temporal 
+operators and functions are available in the expression string. The description of the spatial 
+operators and functions is available in the <a href="r.mapcalc.html">r.mapcalc</a> manual page.
+The temporal functions are described in detail below.
+<p>
+This module expects several parameter. All space time raster datasets that are referenced in 
+the <em>mapcalc expression</em> must be listed in the <em>input</em> option. The <em>first</em> space time raster
+dataset that is listed as input will be used to temporally sample all other
+space time raster datasets. The temporal sampling method can be chosen using
+the <em>method</em> option. The order of the STRDS's in the mapcalc expression can be different 
+to the order of the STRDS's in the input option. The resulting space time raster dataset
+must be specified in the <em>output</em> option together with the <em>base</em> name
+of generated raster maps that are registered in the resulting STRDS. Empty maps
+resulting from map-calculation are not registered by default. This behavior can be changed
+with the <em>-n</em> flag. The flag <em>-s</em> can be used to assure that only spatial related
+maps in the STRDS's are processed. Spatial related means that temporally related maps overlap
+in their spatial extent.
+<p>
+The module <em>t.rast.mapcalc</em> supports parallel processing. The option
+<em>nprocs</em> specifies the number of processes that can be started in parallel. 
+<p>
+A mapcalc expression must be provided to process the temporal 
+sampled maps. Temporal operators are available in addition to 
+the <em>r.mapcalc</em> operators:
+<p>
+Supported functions for relative and absolute time:
+<ul>
+  <li> <em>td()</em> - This function
+       represents the size of the current sample time interval
+       in days and fraction of days for absolute time,
+       and in relative units in case of relative time. </li>
+  <li> <em>start_time()</em> - This function represent 
+    the time difference between the start time of the sample space time
+    raster dataset and the start time of the current sample interval or instance. The time
+    is measured  in days and fraction of days for absolute time,
+    and in relative units in case of relative time. </li>
+  <li> <em>end_time()</em> - This function represent 
+    the time difference between the start time of the sample space time
+    raster dataset and the end time of the current sample interval. The time
+    is measured  in days and fraction of days for absolute time,
+    and in relative units in case of relative time. 
+    The end_time() will be represented by null() in case of a time instance.</li>
+</ul>
+<p>
+Supported functions for absolute time of the current sample interval or instance:
+<ul>
+  <li> <em>start_doy()</em> - Day of year (doy) from the start time [1 - 366] </li>
+  <li> <em>start_dow()</em> - Day of week (dow) from the start time [1 - 7], 
+         the start of the week is monday == 1 </li>
+  <li> <em>start_year()</em> - The year of the start time [0 - 9999] </li>
+  <li> <em>start_month()</em> - The month of the start time [1 - 12] </li>
+  <li> <em>start_week()</em> - Week of year of the start time [1 - 54] </li>
+  <li> <em>start_day()</em> - Day of month from the start time [1 - 31] </li>
+  <li> <em>start_hour()</em> - The hour of the start time [0 - 23] </li>
+  <li> <em>start_minute()</em> - The minute of the start time [0 - 59] </li>
+  <li> <em>start_second()</em> - The second of the start time [0 - 59] </li>
+       
+  <li> <em>end_doy()</em> - Day of year (doy) from the end time [1 - 366] </li>
+  <li> <em>end_dow()</em> - Day of week (dow) from the end time [1 - 7], 
+         the start of the week is monday == 1 </li>
+  <li> <em>end_year()</em> - The year of the end time [0 - 9999] </li>
+  <li> <em>end_month()</em> - The month of the end time [1 - 12] </li>
+  <li> <em>end_woy()</em> - Week of year (woy) of the end time [1 - 54] </li>
+  <li> <em>end_day()</em> - Day of month from the start time [1 - 31] </li>
+  <li> <em>end_hour()</em> - The hour of the end time [0 - 23] </li>
+  <li> <em>end_minute()</em> - The minute of the end time [0 - 59] </li>
+  <li> <em>end_second()</em> - The second of the end time [0 - 59] </li>
+</ul>
+The <em>end_*</em> functions are represented by the null() function in case of time instances.
+
+<h2>NOTE</h2>
+
+We will discuss the internal work of <em>t.rast.mapcalc</em> with an example.
+Imagine we have two STRDS as input, each with monthly granularity. The first one 
+<em>A</em> has 6 raster maps (a3 ... a8) with a temporal range from March to August. The second
+STRDS <em>B</em> has 12 raster maps (b1 ... b12) ranging from January to December. 
+The value of the raster maps is the number of the month from their interval start time.
+Dataset <em>A</em> will be used to sample dataset <em>B</em> to create a dataset <em>C</em>.
+We want to add all maps with equal time stamps if the month of the start time is May or June,
+otherwise we multiply the maps. The command will look as follows:
+<p>
+<div class="code"><pre>
+t.rast.mapcalc input=A,B output=C base=c method=equal \
+    expr="if(start_month() == 5 || start_month() == 6, (A + B), (A * B))"
+</pre></div>
+<p>
+The resulting raster maps in dataset C can be listed with <em>t.rast.list</em>:
+<p>
+<div class="code"><pre>
+name    start_time              min     max
+c_1     2001-03-01 00:00:00     9.0     9.0
+c_2     2001-04-01 00:00:00     16.0    16.0
+c_3     2001-05-01 00:00:00     10.0    10.0
+c_4     2001-06-01 00:00:00     12.0    12.0
+c_5     2001-07-01 00:00:00     49.0    49.0
+c_6     2001-08-01 00:00:00     64.0    64.0
+</pre></div>
+<p>
+Internally the spatio-temporal expression will be analyzed for each time interval
+of the sample dataset A, the temporal functions will be replaced by numerical values,
+the names of the space time raster datasets will be replaced by the corresponding raster maps.
+The final expression will be passed to <em>r.mapcalc</em>, resulting in 6 runs:
+<p>
+<div class="code"><pre>
+r.mapcalc expr="c_1 = if(3 == 5 || 3 == 6, (a3 + b3), (a3 * b3))"
+r.mapcalc expr="c_2 = if(4 == 5 || 4 == 6, (a4 + b4), (a4 * b4))"
+r.mapcalc expr="c_3 = if(5 == 5 || 5 == 6, (a5 + b5), (a5 * b5))"
+r.mapcalc expr="c_4 = if(6 == 5 || 6 == 6, (a6 + b6), (a6 * b6))"
+r.mapcalc expr="c_5 = if(7 == 5 || 7 == 6, (a7 + b7), (a7 * b7))"
+r.mapcalc expr="c_6 = if(8 == 5 || 8 == 6, (a8 + b8), (a8 * b8))"
+</pre></div>
+<p>
+Here the full script to reproduce the example:
+<p>
+<div class="code"><pre>
+g.region s=0 n=80 w=0 e=120 b=0 t=50 res=10 res3=10 -p3
+# Lets create the raster maps
+r.mapcalc  expr="a3 = 3"
+r.mapcalc  expr="a4 = 4"
+r.mapcalc  expr="a5 = 5"
+r.mapcalc  expr="a6 = 6"
+r.mapcalc  expr="a7 = 7"
+r.mapcalc  expr="a8 = 8"
+
+r.mapcalc  expr="b1 = 1"
+r.mapcalc  expr="b2 = 2"
+r.mapcalc  expr="b3 = 3"
+r.mapcalc  expr="b4 = 4"
+r.mapcalc  expr="b5 = 5"
+r.mapcalc  expr="b6 = 6"
+r.mapcalc  expr="b7 = 7"
+r.mapcalc  expr="b8 = 8"
+r.mapcalc  expr="b9 = 8"
+r.mapcalc  expr="b10 = 10"
+r.mapcalc  expr="b11 = 11"
+r.mapcalc  expr="b12 = 12"
+
+t.create  type=strds temporaltype=absolute \
+    output=A title="Dataset A" descr="Dataset A"
+    
+t.create  type=strds temporaltype=absolute \
+    output=B title="Dataset B" descr="Dataset B"
+    
+t.register  -i type=rast input=A maps=a3,a4,a5,a6,a7,a8 \
+    start="2001-03-01" increment="1 months"
+    
+t.register  -i type=rast input=B maps=b1,b2,b3,b4,b5,b6,b7,b8,b9,b10,b11,b12 \
+    start="2001-01-01" increment="1 months"
+
+t.rast.mapcalc input=A,B output=C base=c method=equal \
+    expr="if(start_month() == 5 || start_month() == 6, (A + B), (A * B))"
+
+t.info type=strds input=C
+
+t.rast.list -h input=C columns=name,start_time,min,max
+</pre></div>
+
 
 <h2>SEE ALSO</h2>
 
 <em>
-<a href="t.create.html">t.create</a>,
+<a href="r.mapcalc.html">r.mapcalc</a>,
+<a href="t.register.html">t.register</a>,
+<a href="t.rast.list.html">t.rast.list</a>,
 <a href="t.info.html">t.info</a>
 </em>
 

temporal/t.rast.mapcalc/t.rast.mapcalc.py

@@ -5,7 +5,7 @@
 # MODULE:	t.rast.mapcalc
 # AUTHOR(S):	Soeren Gebbert
 #
-# PURPOSE:	Perform r.mapcalc expressions on maps of sampled space time raster datasets
+# PURPOSE:	Perform spatio-temporal mapcalc expressions on temporal sampled maps of space time raster datasets
 # COPYRIGHT:	(C) 2012 by the GRASS Development Team
 #
 #		This program is free software under the GNU General Public
@@ -15,7 +15,7 @@
 #############################################################################
 
 #%module
-#% description: Performs r.mapcalc expressions on maps of sampled space time raster datasets.
+#% description: Perform spatio-temporal mapcalc expressions on temporal sampled maps of space time raster datasets.
 #% keywords: temporal
 #% keywords: algebra
 #%end
@@ -26,14 +26,14 @@
 #%option
 #% key: expression
 #% type: string
-#% description: r.mapcalc expression applied to each time step of the sampled data
+#% description: Spatio-temporal mapcalc expression
 #% required: yes
 #% multiple: no
 #%end
 
 #%option G_OPT_T_SAMPLE
 #% key: method
-#% answer: during,overlap,contain,equal
+#% answer: equal
 #%end
 
 #%option G_OPT_STRDS_OUTPUT