comp.lang.idl-pvwave archive - RDF feed
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description: Messages from Usenet group comp.lang.idl-pvwave, compiled by Paulo Penteado
items: reversing background color in maps
items: Re: reversing background color in maps

reversing background color in maps
type: item
description: OK, guys and gals... I'm trying to create a plot here that has a world map overplotted with my data positions. I can do that OK. My problem is that it plots as white on a black background. I need to reverse this and have a white background. For simplicity, I'm using the tek_color ct. I thought, hmmm... I'll just swap the black and white entries in the ct, and I'll be set. Right? Like this... ;//Save original color table tvlct, old_r,old_g,old_b, /get ;//Set up colors for plotting tek_color BLACK = 0 WHITE = 1 RED = 2 GREEN = 3 BLUE = 4 ORANGE = 8 ;//Reverse BLACK/WHITE tvlct, 255,255,255,0 tvlct, 0,0,0,1 WHITE = 0 BLACK = 1 When I run it like this, I do get a white background but the box labels (from map_grid,/box) are gone and I get the lat lon grid lines in black even tho I didn't want grid lines at all (/grid not set in map_set). Anybody know of a way to get this workin' correctly?? print, !version { x86 Win32 Windows 5.0.2 Jul 23 1997} I'm kinda in the process of upgrading to 5.2, so please let me know if this works as wanted in 5.2. Thanks alot, t bowers Here's pretty much what the plotting stuff looks like if ya wanna know. ;//Find all unigue lons/lats in data lon = (dataArray[lonIndex,*])[UNIQ(dataArray[lonIndex,*], SORT(dataArray[lonIndex,*]))] lat = (dataArray[latIndex,*])[UNIQ(dataArray[latIndex,*], SORT(dataArray[latIndex,*]))] ;//Append current lon/lat to lon/lat array list. I'll plot these arrays (lons/lats) as data positions lons = [lons,lon] lats = [lats,lat] ;//Set up a margin that's a certain % of lat lon delta. ;// e.g 0.15 = margin extending 15% beyond bounds of data margin = 0.15 ;//I'll use these in upcoming call to map_set minLon = min(lons,max=maxLon) minLat = min(lats,max=maxLat) lonMargin = (maxLon - minLon) * margin latMargin = (maxLat - minLat) * margin midLon = median(lons, /even) midLat = median(lats, /even) ;//Set up map centered on data and extending margin % beyond data positions map_set, midLat, midLon, $ /TRANSVERSE_MERCATOR, $ /ISO…
creator: T Bowers
date: 1999-02-19T08:00:00-00:00

Re: reversing background color in maps
type: item
description: T Bowers <tbowers@nrlssc.navy.mil> wrote: > ...I need to reverse this and have a white background. > tvlct, 255,255,255,0 > tvlct, 0,0,0,1 > WHITE = 0 > BLACK = 1 > When I run it like this, I do get a white background but the box labels > (from map_grid,/box) are gone and I get the lat lon grid lines in black > even tho I didn't want grid lines at all (/grid not set in map_set). As I understand it, IDL plots background using index !p.background and foreground with !p.color. These are normally 0 and 255, and are normally black and white respectively. If you just make index 0 into white, then !p.background and !p.color point to the same colour. So: I think you can just interchange !p.background and !p.color, or if you want to follow your scheme, do tvlct,0,0,0,!p.color & black=!p.color -W. -- William M Connolley | wmc@bas.ac.uk | http://www.nbs.ac.uk/public/icd/wmc/ Climate Modeller, British Antarctic Survey | Disclaimer: I speak for myself
creator: wmc
date: 1999-02-22T08:00:00-00:00