Issue converting reclassified raster to polygon

[tiggerkate]

Hi all,

I'm trying to convert my reclassified raster to polygon to calculate
suitable / unsuitable areas. However I encounter a problem when
attempting to convert my floating-point raster to a polygon (it says
it requires an integer input raster).

Has anyone had a simliar issue and if so, how did you get around it?
I've tried converting the raster to integer but then it converts to
one value across the area and I lose my reclassified values.

Thanks,
Kate

[John Baumgartner]

Hi,

AFAIK, the raster should no longer be floating point after reclassification... if you're working in ArcGIS, are you using the Spatial Analyst "Reclassify" tool?

This *should* work:

1. Convert the ASCII to Raster (with FLOAT selected) (Conversion toolbox). You should now have a continuous, floating point raster.

2. Reclassify (Spatial Analyst toolbox). You should now have a continuous integer raster.

3. Convert Raster to Polygon (uncheck Simplify Polygons if appropriate). The class value should now be in a field called grid code... if you set your symbology to "Categories - Unique Values", and Add All Values, the color scheme should reflect the classification.

Does this not work for you?

I've uploaded an archive containing the outputs for each step of the process to my Dropbox (http://dl.dropbox.com/u/1058849/reclass_example.zip), where it'll be available short-term (bv_hot_rast -> bv_hot_reclas -> bv_hot_poly.shp). The original .asc was bradypus_variegatus_hotlayers.asc, from the Maxent Tutorial example.

John

--
You received this message because you are subscribed to the Google Groups "Maxent" group.
To post to this group, send email to max...@googlegroups.com.
To unsubscribe from this group, send email to maxent+un...@googlegroups.com.
For more options, visit this group at http://groups.google.com/group/maxent?hl=en.

--
John Baumgartner

PhD Candidate

The School of Botany

The University of Melbourne

Parkville, Vic, 3010

Australia

[kate allberry]

Hi John,
 
Thanks loads for your help and yes, it worked fine.
 
I had origianlly reclassified my raster via the TOC (right-clicking the raster and selecting properties > symbology) rather than using the Reclassify tool in Spatial Analyst; oddly enough, by doing it this way it didn't transform to an integer which as you say was the issue.
 
Just a heads up if anyone else has a similar issue in future.
 
Thnaks again.
 
Cheers,
Kate 

---

Date: Wed, 22 Jun 2011 15:56:02 +1000
Subject: Re: Issue converting reclassified raster to polygon
From: joh...@student.unimelb.edu.au
To: max...@googlegroups.com

[John Baumgartner]

No worries. Yep, the symbology settings only affect the visualization of the data, not the underlying data.

:)

John