added module for actual evapotranspiration (i.eb.eta)

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@37967 15284696-431f-4ddb-bdfa-cd5b030d7da7

gui/wxpython/xml/menudata.xml

@@ -2293,9 +2293,16 @@
 	      <command>i.eb.evapfr</command>
 	    </menuitem>
 	    <menuitem>
+	      <label>Actual Evapotranspiration</label>
+	      <help>Computes the actual evapotranspiration (ETa)</help>
+	      <keywords>imagery,energy balance,land flux,actual evapotranspiration</keywords>
+              <handler>self.OnMenuCmd</handler>
+	      <command>i.eb.eta</command>
+	    </menuitem>
+	    <menuitem>
 	      <label>ET Temporal Integration</label>
 	      <help>Temporal integration of satellite ET actual (ETa) following the daily ET reference (ETo) from meteorological station(s)</help>
-	      <keywords>evapotranspiration,temporal,integration</keywords>
+	      <keywords>imagery,evapotranspiration,temporal,integration</keywords>
               <handler>self.OnMenuCmd</handler>
 	      <command>i.evapo.time_integration</command>
 	    </menuitem>
@@ -2697,4 +2704,4 @@
       </items>
     </menu>
   </menubar>
-</menudata>
+</menudata>

imagery/Makefile

@@ -6,6 +6,7 @@ SUBDIRS = \
 	i.cca \
 	i.cluster \
 	i.eb.evapfr \
+	i.eb.eta \
 	i.eb.g0 \
 	i.eb.h_SEBAL01 \
 	i.evapo.time_integration \

imagery/i.eb.eta/Makefile

@@ -0,0 +1,14 @@
+MODULE_TOPDIR = ../..
+
+PGM = i.eb.eta
+
+LIBES = $(GISLIB)
+DEPENDENCIES = $(GISDEP)
+
+include $(MODULE_TOPDIR)/include/Make/Module.make
+
+ifneq ($(USE_LARGEFILES),)
+	EXTRA_CFLAGS = -D_FILE_OFFSET_BITS=64
+endif
+
+default: cmd

imagery/i.eb.eta/eta.c

@@ -0,0 +1,14 @@
+#include<stdio.h>
+#include<math.h>
+
+double et_a(double r_net_day, double evap_fr, double tempk)
+{
+    double latent, t_celsius, result;
+
+    t_celsius = tempk - 273.15;
+    latent = 86400 / ((2.501 - 0.002361 * t_celsius) * pow(10, 6));
+
+    result = r_net_day * evap_fr * latent;
+
+    return result;
+}

imagery/i.eb.eta/i.eb.eta.html

@@ -0,0 +1,46 @@
+<H2>DESCRIPTION</H2>
+
+<EM>i.eb.eta</EM> calculates the actual evapotranspiration (ETa ; mm/d) for diurnal period after [1], implemented in [3].
+It takes input of Diurnal Net Radiation (see r.sun), evaporative fraction (see r.eb.evapfr) and surface skin temperature. 
+
+<H2>NOTES</H2>
+Full ETa processing will need those:
+<ul>
+  <li>i.vi, i.albedo, i.latlong, i.emissivity
+  <li>i.evapo.potrad
+  <li>i.eb.netrad, i.eb.soilheatflux, i.eb.h_sebal01
+  <li>i.eb.evapfr, i.eb.eta
+</ul>
+
+(for time integration: i.evapo.time_integration)
+
+<p>For more details on the algorithms see [1][2][3].
+
+<H2>TODO</H2>
+
+
+<H2>SEE ALSO</H2>
+
+<em>
+<A HREF="r.sun.html">r.sun</A><br>
+<A HREF="i.eb.evapfr.html">i.eb.evapfr</A><br>
+<A HREF="i.eb.netrad.html">i.eb.netrad</A><br>
+</em>
+
+<H2>REFERENCES</H2>
+
+  <p>[1] Bastiaanssen, W.G.M., 1995.
+  Estimation of Land surface paramters by remote sensing under clear-sky conditions. PhD thesis, Wageningen University, Wageningen, The Netherlands.
+
+  <p>[2] Chemin Y., Alexandridis T.A., 2001. Improving spatial resolution of ET seasonal for irrigated rice in Zhanghe, China. Asian Journal of Geoinformatics. 5(1):3-11,2004. 
+
+  <p>[3] Alexandridis T.K., Cherif I., Chemin Y., Silleos N.G., Stavrinos E., Zalidis G.C. Integrated methodology for estimating water use in Mediterranean agricultural areas. Remote Sensing. -(-):,2009. (submitted))
+
+
+<H2>AUTHORS</H2>
+
+Yann Chemin, Asian Institute of Technology, Thailand<BR>
+
+
+<p>
+<i>Last changed: $Date: 2006/10/11 16:40:12 $</i>

imagery/i.eb.eta/main.c

@@ -0,0 +1,143 @@
+
+/****************************************************************************
+ *
+ * MODULE:       i.eb.eta
+ * AUTHOR(S):    Yann Chemin - yann.chemin@gmail.com
+ * PURPOSE:      Calculates the actual evapotranspiration for diurnal period
+ *               as seen in Bastiaanssen (1995) 
+ *
+ * COPYRIGHT:    (C) 2002-2009 by the GRASS Development Team
+ *
+ *               This program is free software under the GNU General Public
+ *   	    	 License (>=v2). Read the file COPYING that comes with GRASS
+ *   	    	 for details.
+ *
+ *****************************************************************************/
+     
+    
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <grass/gis.h>
+#include <grass/glocale.h>
+double et_a(double r_net_day, double evap_fr, double tempk);
+
+int main(int argc, char *argv[]) 
+{
+    int nrows, ncols;
+    int row, col;
+    struct GModule *module;
+    struct Option *input1, *input2, *input3, *output1;
+    struct History history;	/*metadata */
+    char *result1;		/*output raster name */
+    int infd_rnetday, infd_evapfr, infd_tempk;
+    int outfd1;
+    char *rnetday, *evapfr, *tempk;
+    void *inrast_rnetday, *inrast_evapfr, *inrast_tempk;
+
+    DCELL * outrast1;
+    G_gisinit(argv[0]);
+
+    module = G_define_module();
+    module->keywords = _("imagery, actual evapotranspiration, energy balance, SEBAL");
+    module->description =
+	_("actual evapotranspiration for diurnal period (Bastiaanssen, 1995)");
+    
+    /* Define the different options */ 
+    input1 = G_define_standard_option(G_OPT_R_INPUT);
+    input1->key = "rnetday";
+    input1->description = _("Name of the diurnal Net Radiation map [W/m2]");
+    input1->answer = "rnetday";
+
+    input2 = G_define_standard_option(G_OPT_R_INPUT);
+    input2->key = "evapfr";
+    input2->description = _("Name of the evaporative fraction map [-]");
+    input2->answer = "evapfr";
+
+    input3 = G_define_standard_option(G_OPT_R_INPUT);
+    input3->key = "tempk";
+    input3->description = _("Name of the surface skin temperature [K]");
+    input3->answer = "tempk";
+
+    output1 = G_define_standard_option(G_OPT_R_OUTPUT);
+    output1->description =
+	_("Name of the output actual evapotranspiration layer [mm/d]");
+    output1->answer = "eta";
+
+    if (G_parser(argc, argv))
+        exit(EXIT_FAILURE);
+
+    rnetday = input1->answer;
+    evapfr = input2->answer;
+    tempk = input3->answer;
+    result1 = output1->answer;
+    
+    if ((infd_rnetday = G_open_cell_old(rnetday, "")) < 0)
+	G_fatal_error(_("Unable to open raster map <%s>"), rnetday);
+    inrast_rnetday = G_allocate_d_raster_buf();
+    
+    if ((infd_evapfr = G_open_cell_old(evapfr, "")) < 0)
+	G_fatal_error(_("Unable to open raster map <%s>"), evapfr);
+    inrast_evapfr = G_allocate_d_raster_buf();
+    
+    if ((infd_tempk = G_open_cell_old(tempk, "")) < 0)
+	G_fatal_error(_("Unable to open raster map <%s>"), tempk);
+    inrast_tempk = G_allocate_d_raster_buf();
+    
+    nrows = G_window_rows();
+    ncols = G_window_cols();
+    outrast1 = G_allocate_d_raster_buf();
+    
+    if ((outfd1 = G_open_raster_new(result1, DCELL_TYPE)) < 0)
+        G_fatal_error(_("Unable to create raster map <%s>"), result1);
+    
+    /* Process pixels */ 
+    for (row = 0; row < nrows; row++)
+    {
+        DCELL d;
+	DCELL d_rnetday;
+	DCELL d_evapfr;
+	DCELL d_tempk;
+	G_percent(row, nrows, 2);
+	
+	/* read input maps */ 
+	if (G_get_d_raster_row(infd_rnetday,inrast_rnetday,row)<0)
+	    G_fatal_error(_("Unable to read from <%s> row %d"), rnetday, row);
+	if (G_get_d_raster_row(infd_evapfr,inrast_evapfr,row)<0)
+	    G_fatal_error(_("Unable to read from <%s> row %d"), evapfr, row);
+	if (G_get_d_raster_row(infd_tempk,inrast_tempk,row)<0)
+	    G_fatal_error(_("Unable to read from <%s> row %d"), tempk, row);
+	
+    /*process the data */ 
+    for (col = 0; col < ncols; col++)
+    {
+            d_rnetday = ((DCELL *) inrast_rnetday)[col];
+            d_evapfr = ((DCELL *) inrast_evapfr)[col];
+            d_tempk = ((DCELL *) inrast_tempk)[col];
+	    if (G_is_d_null_value(&d_rnetday) ||
+		 G_is_d_null_value(&d_evapfr) ||
+		 G_is_d_null_value(&d_tempk)) 
+		G_set_d_null_value(&outrast1[col], 1);
+	    else {
+		d = et_a(d_rnetday, d_evapfr, d_tempk);
+		outrast1[col] = d;
+	    }
+	}
+	if (G_put_d_raster_row(outfd1,outrast1) < 0)
+	    G_fatal_error(_("Failed writing raster map <%s>"), result1);
+    }
+    G_free(inrast_rnetday);
+    G_free(inrast_evapfr);
+    G_free(inrast_tempk);
+    G_close_cell(infd_rnetday);
+    G_close_cell(infd_evapfr);
+    G_close_cell(infd_tempk);
+    G_free(outrast1);
+    G_close_cell(outfd1);
+    G_short_history(result1, "raster", &history);
+    G_command_history(&history);
+    G_write_history(result1, &history);
+    exit(EXIT_SUCCESS);
+}
+
+