<div>thanks everyone,</div>
<div> </div>
<div>i'll try r.sun, but i thought i'd like the freedom of running my own algorithms- i'm not sure i'll have access to the papers that are referred to in the r.sun help page, to check out the algorithm.</div>
<div> </div>
<div>meanwhile, here is what i'd like to do, using either r.sun or my own algorithms. If you can suggest some <strong>general</strong> steps, that would speed up my attempts:</div>
<div> </div>
<div>I want to create a monthly map of extraterrestrial radiation, and net radiation, on a 0.5 degree grid for extents 60 -100.5E and 5 to 45.5N. I am not particular about corrections for aspect and slope at this point. So particular questions i have now are:
</div>
<div>a) I already have a location with the above coordinates and cell size. Can i use r.sun on an empty map or do i absolutely need an elevations, slope and aspetc map?</div>
<div> </div>
<div>b) At this point i can only derive monthly radiation maps by summing the daily estimates in r.sun- right?</div>
<div> </div>
<div>thanks all!</div>
<div>vishal<br><br> </div>
<div><span class="gmail_quote">On 3/27/06, <b class="gmail_sendername">Glynn Clements</b> <<a href="mailto:glynn@gclements.plus.com">glynn@gclements.plus.com</a>> wrote:</span>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid"><br>Vishal Mehta wrote:<br><br>> I have a raster map, lat/long, 0.5 degrees resolution. I want to develop
<br>> solar radiation and related maps maps using r.mapcalc. This requires<br>> refering to each cell's latitude and longitude, i.e. the equations will<br>> include the cell's latitude and longitude. How do i do this in GRASS? Is
<br>> there like an intenral variable that indexes each cell's coordinates?<br><br>In r.mapcalc, the x() and y() functions return the coordinates of the<br>centre of the current cell.<br><br>--<br>Glynn Clements <<a href="mailto:glynn@gclements.plus.com">
glynn@gclements.plus.com</a>><br></blockquote></div><br>