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Projected Meter Space and mapCoord [message #88967]

Wed, 09 July 2014 06:48

morganlsilverman
Messages: 46
Registered: February 2013

Member

Hello,

I'm looking more just for clarification so that I can understand further. I understand that latitude and longitude points have to be converted into projected meter space to be correctly placed on a map background. I've run my code 2 different ways, first using

city_lats = [ 39.75, 41.29, 33.84, 45.49, 47.62, 40.22]
city_lons = [ -105.00, -95.92, -84.38, -122.69, -122.34, -74.78]
xy = mapCoord->Forward(city_lons, city_lats)
city_x = Reform(xy[0,*])
city_y = Reform(xy[1,*])
cgPlotS, city_x[j], city_y[j], Color=Byte(j+1), PSYM=16, SYMSize=2.0

and the second just using
city_lats = [ 39.75, 41.29, 33.84, 45.49, 47.62, 40.22]
city_lons = [ -105.00, -95.92, -84.38, -122.69, -122.34, -74.78]
cgPlotS, city_lons(j), city_lats(j), map=mapCoord, Color=Byte(j+1), PSYM=16, SYMSize=2.0

mapCoord has already been defined in both cases. I just abbreviated the code for simplicity. It appears that both graph exactly the same and look correct. I'm wondering if this is true and if it matters what method you use or if one is better, mapCoord->Forward(lon,lat) or cgPlotS, map=mapCoord. I would like to do things correctly and not incorrect but still have them seem to work for some reason.

Thanks.
-Morgan

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[Message index]

		Projected Meter Space and mapCoord By: morganlsilverman on Wed, 09 July 2014 06:48
		Re: Projected Meter Space and mapCoord By: David Fanning on Wed, 09 July 2014 07:00
		Re: Projected Meter Space and mapCoord By: morganlsilverman on Wed, 09 July 2014 07:30
		Re: Projected Meter Space and mapCoord By: David Fanning on Wed, 09 July 2014 07:38
		Re: Projected Meter Space and mapCoord By: Phillip Bitzer on Wed, 09 July 2014 07:01

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