[GRASS-SVN] r51491 - grass/trunk/raster/r.watershed/front
svn_grass at osgeo.org
svn_grass at osgeo.org
Mon Apr 23 08:45:19 EDT 2012
Author: mmetz
Date: 2012-04-23 05:45:19 -0700 (Mon, 23 Apr 2012)
New Revision: 51491
Modified:
grass/trunk/raster/r.watershed/front/main.c
grass/trunk/raster/r.watershed/front/r.watershed.html
Log:
r.watershed: add TCI, update manual
Modified: grass/trunk/raster/r.watershed/front/main.c
===================================================================
--- grass/trunk/raster/r.watershed/front/main.c 2012-04-23 12:44:53 UTC (rev 51490)
+++ grass/trunk/raster/r.watershed/front/main.c 2012-04-23 12:45:19 UTC (rev 51491)
@@ -57,6 +57,7 @@
struct Option *opt14;
struct Option *opt15;
struct Option *opt16;
+ struct Option *opt17;
struct Flag *flag_sfd;
struct Flag *flag_flow;
struct Flag *flag_seg;
@@ -130,6 +131,13 @@
opt8->required = NO;
opt8->guisection = _("Outputs");
+ opt17 = G_define_standard_option(G_OPT_R_OUTPUT);
+ opt17->key = "tci";
+ opt17->label =
+ _("Topographic index ln(a / tan(b))");
+ opt17->required = NO;
+ opt17->guisection = _("Outputs");
+
opt9 = G_define_standard_option(G_OPT_R_OUTPUT);
opt9->key = "drainage";
opt9->description = _("Name for output drainage direction raster map");
@@ -288,6 +296,7 @@
do_opt(opt6);
do_opt(opt7);
do_opt(opt8);
+ do_opt(opt17);
do_opt(opt9);
do_opt(opt10);
do_opt(opt11);
@@ -311,6 +320,10 @@
write_hist(opt8->answer,
"Watershed accumulation: overland flow that traverses each cell",
opt1->answer, flag_seg->answer, flag_sfd->answer);
+ if (opt17->answer)
+ write_hist(opt8->answer,
+ "Watershed accumulation: topographic index ln(a / tan b)",
+ opt1->answer, flag_seg->answer, flag_sfd->answer);
if (opt9->answer)
write_hist(opt9->answer,
"Watershed drainage direction (CCW from East divided by 45deg)",
Modified: grass/trunk/raster/r.watershed/front/r.watershed.html
===================================================================
--- grass/trunk/raster/r.watershed/front/r.watershed.html 2012-04-23 12:44:53 UTC (rev 51490)
+++ grass/trunk/raster/r.watershed/front/r.watershed.html 2012-04-23 12:45:19 UTC (rev 51491)
@@ -123,6 +123,16 @@
negative values cannot have their surface runoff and sedimentation yields
calculated accurately.
+<dt><em>tci</em>
+
+<dd>Output map: The topographic index TCI is computed as
+<em>ln(α / tan(β))</em> where α a is the cumulative
+uplsope area draining through a point per unit contour length and
+tan(β) is the local slope angle. The TCI reflects the tendency of
+water to accumulate at any point in the catchment and the tendency for
+gravitaional forces to move that water downslope (Quinn et al. 1991).
+This value will be negative if α / tan(β) < 1.
+
<dt><em>drainage</em>
<dd>Output map: drainage direction. Provides the "aspect" for each
@@ -247,6 +257,9 @@
of <em>seg</em>.
<h3>Large regions with many cells</h3>
+The upper limit of the <em>ram</em> version is 2 billion
+(2<sup>31</sup> - 1) cells, whereas the upper limit for the <em>seg</em>
+version is 9 billion billion (2<sup>63</sup> - 1) cells.<br>
In some situations, the region size (number of cells) may be too large for
the amount of time or memory available. Running <em>r.watershed</em> may
then require use of a coarser resolution. To make the results more closely
@@ -431,7 +444,7 @@
<h2>REFERENCES</h2>
-Ehlschlaeger, C. (1989). <i>Using the A<sup>T</sup> Search Algorithm
+Ehlschlaeger C. (1989). <i>Using the A<sup>T</sup> Search Algorithm
to Develop Hydrologic Models from Digital Elevation Data</i>,
<b>Proceedings of International Geographic Information Systems (IGIS)
Symposium '89</b>, pp 275-281 (Baltimore, MD, 18-19 March 1989).<br>
@@ -439,13 +452,13 @@
http://chuck.ehlschlaeger.info/older/IGIS/paper.html</a>
<p>
-Holmgren, P. (1994). <i>Multiple flow direction algorithms for runoff
+Holmgren P. (1994). <i>Multiple flow direction algorithms for runoff
modelling in grid based elevation models: An empirical evaluation.</i>
-<b>Hydrological Processes</b> Vol 8(4), p.327-334.<br>
+<b>Hydrological Processes</b> Vol 8(4), 327-334.<br>
DOI: <a href="http://dx.doi.org/10.1002/hyp.3360080405">10.1002/hyp.3360080405</a>
<p>
-Kinner D., H. Mitasova, R. Harmon, L. Toma, R., Stallard. (2005).
+Kinner D., Mitasova H., Harmon R., Toma L., Stallard R. (2005).
<i>GIS-based Stream Network Analysis for The Chagres River Basin,
Republic of Panama</i>. <b>The Rio Chagres: A Multidisciplinary Profile of
a Tropical Watershed</b>, R. Harmon (Ed.), Springer/Kluwer, p.83-95.<br>
@@ -457,7 +470,20 @@
Soil Loss Equation</i>, <b>Transactions of the ASAE</b> Vol 30(5).
<p>
-Weltz M. A., K. G. Renard, J. R. Simanton (1987). <i>Revised Universal Soil
+Metz M., Mitasova H., Harmon R. (2011). <i>Efficient extraction of
+drainage networks from massive, radar-based elevation models with least
+cost path search</i>, <b>Hydrol. Earth Syst. Sci.</b> Vol 15, 667-678.<br>
+DOI: <a href="http://dx.doi.org/10.5194/hess-15-667-2011">10.5194/hess-15-667-2011</a>
+
+<p>
+Quinn P., K. Beven K., Chevallier P., Planchon O. (1991). <i>The
+prediction of hillslope flow paths for distributed hydrological modelling
+using Digital Elevation Models</i>, <b>Hydrological Processes</b> Vol 5(1),
+p.59-79.<br>
+DOI: <a href="http://dx.doi.org/10.1002/hyp.3360050106">10.1002/hyp.3360050106</a>
+
+<p>
+Weltz M. A., Renard K.G., Simanton J. R. (1987). <i>Revised Universal Soil
Loss Equation for Western Rangelands</i>, <b>U.S.A./Mexico Symposium of
Strategies for Classification and Management of Native Vegetation for
Food Production In Arid Zones</b> (Tucson, AZ, 12-16 Oct. 1987).
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