topic Re: Points within a polygon in Geoprocessing Questions

Points within a polygon

SeanGerhardt — Thu, 21 Apr 2011 00:33:25 GMT

Hey everyone,

What tool can one use that tells you if a point lies within a shape? (Point shapefile with point that is within a shape polygon's area.)

Thanks in advance!

Re: Points within a polygon

JeffLee — Thu, 21 Apr 2011 01:12:28 GMT

I can think of two right of the bat. You can do a select by location on your point file with the relevant polygon feature selected, or a point on polygon intersection.

Re: Points within a polygon

JustinOdell — Thu, 21 Apr 2011 01:16:11 GMT

The intersect tool should do this for you.

Or else, if you go to the Selection Menu and choose 'Select by Location' you should be able to use the 'intersect' spatial selection option to intersect between the two layers.

Hope this helps!

Re: Points within a polygon

SeanGerhardt — Fri, 29 Apr 2011 14:13:14 GMT

Alright Thank you guys so much! That did the trick.

Would you guys also happen to know how to convert a .lyr or raster image to a point shapefile?

What I eventually want to do is a pixel by pixel analysis, so I would need to convert every pixel of a layer or raster image(landsat 7 image) to a point. Any ideas?

Re: Points within a polygon

JustinOdell — Sun, 01 May 2011 23:19:11 GMT

Info on converting Lyr to SHP:
http://forums.esri.com/Thread.asp?c=93&f=1149&t=296657

There is also a 'Raster to Point' geoprocessing tool available in ArcMap. Try reading up about the tool so you have a better understanding of how it works.
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//001200000007000000.htm

Re: Points within a polygon

SeanGerhardt — Tue, 03 May 2011 17:08:48 GMT

Thank you very much. I was able to convert a landsat image to a point shapefile, which was very nice. (68 million points!) Unfortunately from what I read, most .lyr files can not be converted to a point feature if they don't have associated "data". Hence I was not able to convert a higher resolution esri world imagery .lyr file to a point feature. I would imagine the number of points would be astronimcal, unless there is a way to specifically choose a portion(crop tool or something of the like?) of the .lyr or other image you want to convert to a shapefile. At any rate this has been very informative and I thank you all for your assitance. : )