topic Re: How can I create Boundaries/Polygons from Points for use in PROC SGMAP choromap statement in Graphics Programming

How can I create Boundaries/Polygons from Points for use in PROC SGMAP choromap statement

tgrandchamp — Wed, 07 Nov 2018 17:14:05 GMT

I am trying to create a dataset of geographic (Lat& Long based) polygon boundaries similar to the mapsgfk.us_counties data set. With the goal of displaying polygons of the resulting polygons using a choromap statement in PROC SGMAP.

The data I have to start with are individual latitude and longitude variables for data points within a given polygon. How can i use these individual Lat & Long datapoints to generate the boundry information necessary to use the choromap statement to create a polygon that overlays the area containing the individual data points.

Basically I am trying to take the plot data from the top image and create the boundry polygon on the bottom image:

Re: How can I create Boundaries/Polygons from Points for use in PROC SGMAP choromap statement

ballardw — Wed, 07 Nov 2018 23:08:18 GMT

Please do not post essentially Identical questions on this forum.

I leads to confused responses across threads, duplicate or similar comments by different folks unaware of the "other thread" and makes others searching the forum have more difficulty finding solutions on similar topics.

Re: How can I create Boundaries/Polygons from Points for use in PROC SGMAP choromap statement

GraphGuy — Fri, 09 Nov 2018 13:34:07 GMT

You could perhaps start with the polygons for a Census block map, and then use Proc Ginside to determine what Census blocks your points are 'inside' of, and then color those Census blocks red. Or, one step further, you could run Proc Gremove (to remove internal Census block boundaries) and create a single polygon for the area.