topic Re: How to plot some events over latitude and longitude data in Graphics Programming

How to plot some events over latitude and longitude data

munitech4u — Tue, 16 Aug 2016 11:54:26 GMT

I have 3 columns in a dataset:

Latitude Logitude Phone

-89.2132 179.9323 A

34.1231 -85.123 B

23.45 -34.23 A

.....

It is a customer level data, where phone category can be A or B, I want to plot these categories over the Latitude and Logitude data in SAS, where A and B can take 2 different colors.

Re: How to plot some events over latitude and longitude data

ballardw — Tue, 16 Aug 2016 11:49:17 GMT

Is there supposed to be a map involved?

What units are those latitude and longititude values supposed to be in? Latitude typically uses degrees with a range of -90 to 90 and longitude -180 to 180 degrees.

Re: How to plot some events over latitude and longitude data

munitech4u — Tue, 16 Aug 2016 11:53:17 GMT

Map may not be necessary, but will be great if, we can have it. Yes, they are in degrees as you specified

Re: How to plot some events over latitude and longitude data

BrunoMueller — Tue, 16 Aug 2016 11:57:08 GMT

with SAS/GRAPH you will get libraries named MAPS and MAPSGFK using the provided data and ODS GRAPHICS you can create maps. See the attachment for the example.

Here is an example:

/*
 * create the map data
 * use the resolution var to have less data points
 * create a new ID var for drawing the map
 */ 
data map_data;
  length id_c $ 32;
  set mapsgfk.europe;
  where
    resolution <= 3
  ;
  id_c = catx("_", id, segment);
run;

/*
 * create the data for locations
 * NOTE: use a different name for the latitude and longitude variables
 */
data locations;
  infile cards;
  input
    lat2
    Long2
    Phone $
  ;
cards;
50.598726 9.450487 A
52.201658 -1.730536 B
;

/*
 * concat the two data sets
 */
data plotdata;
  set map_data locations;
run;
 

/*
 * draw the map using SGPLOT
 * the POLYGON will draw the map
 * the SCATTER will plot data points
 */
ods graphics / width=1600 height=1200 ;

proc sgplot data=plotdata  ;
  styleattrs
    datasymbols=(diamondFilled squareFilled)
  ; 
  polygon x=long y=lat id=id_c / group=id fill  outline name="map";

  scatter x=long2 y=lat2 / group=Phone markerattrs=(size=15) name="loc";
  keylegend "loc";
  xaxis display=none;
  yaxis display=none;
run;

Bruno

Re: How to plot some events over latitude and longitude data

munitech4u — Tue, 16 Aug 2016 12:20:29 GMT

I have about 1 million observation, how can i make it more visible friendly?

Re: How to plot some events over latitude and longitude data

Rick_SAS — Tue, 16 Aug 2016 13:23:21 GMT

If you have overplotting, you can use transparency to attempt to reduce overplotting:

scatter x=long2 y=lat2 / group=Phone name="loc" transparency=0.9;

If you have millions of points, you might also consider plotting the density of the data, rather than individual markers. You can use PROC KDE or check out the hexagonal binning macro that can create a density map.

Re: How to plot some events over latitude and longitude data

munitech4u — Wed, 17 Aug 2016 08:35:31 GMT

I tried the transparency option as well. But the graph looks really bad.

Re: How to plot some events over latitude and longitude data

BrunoMueller — Wed, 17 Aug 2016 09:05:44 GMT

I would make the marker size smaller.

Some questions:

Please explain, what the viewer of the graph should be able to read out of this graph?

Do many points have the same coordinates, for instance based on the ZIP code?

Bruno

Re: How to plot some events over latitude and longitude data

munitech4u — Wed, 17 Aug 2016 09:47:38 GMT

I tried reducing the marker size, but I am not able to distinguish the 2 cases. How can I make the 2 cases visible and more bigger? I am fine, even if i don't include the map, just the scales of latitude and longitude

For your questions:
1. I want to see the density of both the cases across the longitude and latitude.
2. About the 95% of the points have different coordinates. 5% might be same.