points sampling

[MilanBudhathoki1]

Hi everyone,

I have 35,000 points datasets. It is tedious to incorporate all points for my analysis. I am trying to generate random sample points in ArcGIS 9.3.1 platform. Is it possible run sampling technique in ArcGIS 9.3.1?


Thanks!

[SteveLynch]

Look at "Create Subsets" in 9.3
http://webhelp.esri.com/arcgisdesktop/9.3/index.cfm?id=4003&pid=3999&topicname=Extending_ArcMap_with...


or add a field to your dataset and use the "Calculate Field" GP tool using the following Python expression
arcgis.rand("Integer 0 100") (you'll have to modidy the 0 100)

or in ArcGIS 10, use the Subset Features GP tool

-Steve

[MilanBudhathoki1]

Thank you Lynch !

Your instruction was handy.

[MalenaVargas]

I dont have Geoestatistical analyst and I want to make a random selection over points. I need help urgently!!!

[TarunJaiswal]

I dont have Geoestatistical analyst and I want to make a random selection over points. I need help urgently!!!

You can always get a 60 day trial version of Geostatistical Analyst.

[EricKrause]

You can also use Python's random number generator to get random subsets.

Let's say you have 100 points in your feature class, and you want a subset of 70 random points.  Make a new Short Integer field in the feature class, then use Calculate Field.  Make sure you change from VB to Python, and use this code:
arcgis.rand("Integer 1 100")

Then sort the Attribute table by the random number, and select the first 70 records.

[SteveLynch]

or you can read the post (05-19-2011 02:13 PM) in this thread

Steve