<div dir="ltr"><div><div style="font-size:12.8px">Update: </div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px">I have no idea if this is right in terms of making a 6-hr time-stepped total snow accumulation map but this is what ended up producing results similar to other 10:1 snow accum plots on other sites.</div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px"><div>'define snow = sum(maskout(weasdsfc-weasdsfc(t-1),weasdsfc-weasdsfc(t-1)),t=2,t='%i%')'</div><div>'d const((snow), 0, -u)'</div></div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px">That appears to discard the negative numbers replacing them with 0, at least from my little bit of testing so far. BTW, is there anyway to increase GrADS memory buffer or something? It's kinda blah having to regrid a gxout grid to 1 in order to plot things without GrADS crashing.</div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px">My only concern left at this point is... unless weasdsfc auto-incorporates a 10:1 ratio, how the heck is my plot outputting almost, if not, identical results to other 6-hr snow accum maps that plot 10:1 ratio? </div></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Sat, Sep 26, 2015 at 1:33 PM, Christopher Gilroy <span dir="ltr"><<a href="mailto:chris.gilroy@gmail.com" target="_blank">chris.gilroy@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><p dir="ltr">Hey Jeff, I'm basically just trying to plot total snow accumulation. The formula, if im not mistaken is how you would want it done in terms of giving you a total snowfall amount. So realistically hr 0 is expected to be blank. hr 6 would show snowfall accum between 0-6, hr 12 would then show snowfall accum between 0-12, hr 18 would be 0-18, etc. Of course well then be coupling this with a 10:1 or 15:1 ratio.</p><div class="HOEnZb"><div class="h5">
<div class="gmail_quote">On Sep 26, 2015 11:06 AM, "Jeff Duda" <<a href="mailto:jeffduda319@gmail.com" target="_blank">jeffduda319@gmail.com</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div>I'm pretty sure the white areas (with no numbers plotted) are being set to missing because the mask expression is negative there. Plot weasdsfc-weasdsfc(t-1) alone. I bet you'll see negative numbers there. Seems reasonable that means snow melted so that there is less snow than there was the time step before. Is weasdsfc the only snow variable you have? Memory tells me that the standard GFS data also have a categorical precip type array as well as a snow ratio estimation, so you can couple that with apcpsfc to get an estimation of snow precipitation if that's what you're looking for.<br><br></div>Jeff Duda<br></div><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Sep 25, 2015 at 11:55 PM, Christopher Gilroy <span dir="ltr"><<a href="mailto:chris.gilroy@gmail.com" target="_blank">chris.gilroy@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Hey guys, I'm kinda getting there, but I've run into another problem, and I have no idea at all what's causing this. But when I use 'd weasdsfc' everything is colored. When I do (the "right" way to do 6-hr snow accum?): 'd sum(maskout(weasdsfc-weasdsfc(t-1),weasdsfc-weasdsfc(t-1)),t=2,t='%i%')' I get the attached image output.<div><br></div><div>Any guesses? :-/</div><div><br></div><div>Note: This is a super-zoomed in area of Alaska, since I was debugging and thinking maybe grads was hitting a memory limit or something, but it happens regardless and I know it's related to that expression. :-/</div><div><br></div><div><a href="http://i.imgur.com/CKAfnIy.png" target="_blank">http://i.imgur.com/CKAfnIy.png</a><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Sep 25, 2015 at 10:56 AM, Jennifer Adams <span dir="ltr"><<a href="mailto:jma@cola.iges.org" target="_blank">jma@cola.iges.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word">Hi, Chris — <div><br></div><div>Here’s how I think the numbers could be drawn in the sample from WeatherBell. </div><div>1. You have a particular grid point in mind, with a specific lat/lon </div><div>2. Set lat/lon to a range of values and draw the spatially varying graphic with shaded contours to set up the scaling.</div><div>3. Use ‘q w2xy’ to get the position of the lat/lon on the page, GrADS will return something like "X = 2.72222 Y = 5.58333”. Parse these with substr() to retain the x,y positions.</div><div><br></div><div>4. Fix lat/lon to the desired coordinates, display the variable, which should just print some text to the screen like “Result value = 0.33”</div><div>5. Parse that result to extract the value: val=subwrd(result,4)</div><div>6. use ‘draw string’ with the x,y positions and the data value to place the number on top of the shaded contours. </div><div><br></div><div>If the numbers are based on station data, then it’s a different ball of wax. </div><div>—Jennifer</div><div><br></div><div><br></div><div><br></div><div><br></div><div><div><div><br><div><div>On Sep 25, 2015, at 9:59 AM, Christopher Gilroy <<a href="mailto:chris.gilroy@gmail.com" target="_blank">chris.gilroy@gmail.com</a>> wrote:</div><br><blockquote type="cite"><div dir="ltr">I do want it to draw snowfall amounts, but like in the two images, not "griddy". If you look at, <a href="http://blog.chron.com/weather/wp-content/blogs.dir/2579/files/2014/01/gfs_6hr_snow_acc_se_19.png" target="_blank">http://blog.chron.com/weather/wp-content/blogs.dir/2579/files/2014/01/gfs_6hr_snow_acc_se_19.png</a> that doesn't appear to be drawing those numbers based on a grid at all. They are all scattered about on the map with no real "grid" structure to them. The only way I know how to "control" the frequency (perhaps "stepping" might be a better word?) of the drawing of values would really be to maskout coupled with re-gridding so it doesn't put a number on every possible area that weasdsfc has a value for is. If that makes sense?<br></div><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Sep 25, 2015 at 9:53 AM, Stephen McMillan <span dir="ltr"><<a href="mailto:smcmillan@planalytics.com" target="_blank">smcmillan@planalytics.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Hello Chris,<div><br></div><div>If you don't want to display all the grid values, then you can use 'draw string...' using the coordinates of whatever stations or locations you want displayed on top of the shaded contours. See <a href="http://www.iges.org/grads/gadoc/gradcomddrawstring.html" target="_blank">http://www.iges.org/grads/gadoc/gradcomddrawstring.html</a></div><div><br></div><div>Stephen McMillan</div></div><div class="gmail_extra"><br><div class="gmail_quote"><div><div>On Fri, Sep 25, 2015 at 8:55 AM, Christopher Gilroy <span dir="ltr"><<a href="mailto:chris.gilroy@gmail.com" target="_blank">chris.gilroy@gmail.com</a>></span> wrote:<br></div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div><div dir="ltr"><span style="font-size:12.8px">I'm trying to plot something like this: </span><a href="http://i60.tinypic.com/2v9voe0.jpg" style="font-size:12.8px" target="_blank">http://i60.tinypic.com/2v9voe0.jpg</a><span style="font-size:12.8px"> (WXBell has the same basic setup, </span><a href="http://blog.chron.com/weather/wp-content/blogs.dir/2579/files/2014/01/gfs_6hr_snow_acc_se_19.png" style="font-size:12.8px" target="_blank">http://blog.chron.com/weather/wp-content/blogs.dir/2579/files/2014/01/gfs_6hr_snow_acc_se_19.png</a><span style="font-size:12.8px">) with the inch's plotting on-top of the shaded area but the only way I know how to display "values" like that is with gxout grid, which then makes the numbers plot in grids (obviously) and unless I'm missing something with options I don't see a way to make it output as "loose" as theirs are, instead of literally in a "grid" (square box) format.</span><div style="font-size:12.8px"><br></div><div style="font-size:12.8px">I'm currently simply doing:</div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px"><div>'set gxout grid'</div><div>'set gridln off'</div><div>'set dignum 1'</div><div>'set digsiz 0.05'<br></div><div>'d re(maskout(weasdsfc, weasdsfc-3), 0.25)'<br></div></div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px">Which, you can image it will output tons of numbers all over, making it completely illegible. Any clue on how to do something like the above two images?</div><span><font color="#888888"><div><br></div>-- <br><div>-Chris A. Gilroy</div>
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<span style="border-collapse:separate;border-spacing:0px"><span style="border-collapse:separate;color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><div>--</div><div>Jennifer M. Adams<br>Center for Ocean-Land-Atmosphere Studies (COLA)<br>111 Research Hall, Mail Stop 2B3<br>George Mason University<br>4400 University Drive<br>Fairfax, VA 22030 <br><br></div><div><br></div><br></span></span><br>
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