topic Why &amp;quot;valid semivariogram model couldn't be calculated&amp;quot;? in ArcGIS GeoStatistical Analyst Questions https://community.esri.com/t5/arcgis-geostatistical-analyst-questions/why-amp-quot-valid-semivariogram-model-couldn-t-be/m-p/645496#M1449 <HTML><HEAD></HEAD><BODY><SPAN>Hi,</SPAN><BR /><BR /><SPAN>I have been examining my different semivariogram models to get parameter estimates for my data set using the geostat wizard, ArcGIS 9.3.</SPAN><BR /><BR /><SPAN>A "valid semivariogram model couldn't be calculated" per geostat wizard, when I choose trend as 'constant' using universal kriging.&nbsp; </SPAN><BR /><SPAN>However it does give me semivariogram and estimated parameters if I specify '1st order'.&nbsp; </SPAN><BR /><SPAN>Similarly, it could not be calculated using ordinary kriging unless I specify to remove 1st order trend. </SPAN><BR /><BR /><SPAN>Under what situation, won't the wizard calculate semivariance and estimate parameters when no or constant trend is specified in the semivariogram modeling?</SPAN><BR /><SPAN>Does it prevent estimation if there's a trend and 'constant' trend is not adequate for data?</SPAN><BR /><BR /><SPAN>Thanks in advance!</SPAN></BODY></HTML> Tue, 04 Oct 2011 23:23:28 GMT YukoStender 2011-10-04T23:23:28Z Why &quot;valid semivariogram model couldn't be calculated&quot;? https://community.esri.com/t5/arcgis-geostatistical-analyst-questions/why-amp-quot-valid-semivariogram-model-couldn-t-be/m-p/645496#M1449 <HTML><HEAD></HEAD><BODY><SPAN>Hi,</SPAN><BR /><BR /><SPAN>I have been examining my different semivariogram models to get parameter estimates for my data set using the geostat wizard, ArcGIS 9.3.</SPAN><BR /><BR /><SPAN>A "valid semivariogram model couldn't be calculated" per geostat wizard, when I choose trend as 'constant' using universal kriging.&nbsp; </SPAN><BR /><SPAN>However it does give me semivariogram and estimated parameters if I specify '1st order'.&nbsp; </SPAN><BR /><SPAN>Similarly, it could not be calculated using ordinary kriging unless I specify to remove 1st order trend. </SPAN><BR /><BR /><SPAN>Under what situation, won't the wizard calculate semivariance and estimate parameters when no or constant trend is specified in the semivariogram modeling?</SPAN><BR /><SPAN>Does it prevent estimation if there's a trend and 'constant' trend is not adequate for data?</SPAN><BR /><BR /><SPAN>Thanks in advance!</SPAN></BODY></HTML> Tue, 04 Oct 2011 23:23:28 GMT https://community.esri.com/t5/arcgis-geostatistical-analyst-questions/why-amp-quot-valid-semivariogram-model-couldn-t-be/m-p/645496#M1449 YukoStender 2011-10-04T23:23:28Z Re: Why "valid semivariogram model couldn't be calculated"? https://community.esri.com/t5/arcgis-geostatistical-analyst-questions/why-amp-quot-valid-semivariogram-model-couldn-t-be/m-p/645497#M1450 <HTML><HEAD></HEAD><BODY><SPAN>Can you send your data to </SPAN><A href="mailto:ekrause@esri.com">ekrause@esri.com</A><SPAN>?&nbsp; I'll take a look and try to figure out what is causing the problem.&nbsp; Thanks.</SPAN></BODY></HTML> Thu, 06 Oct 2011 13:34:12 GMT https://community.esri.com/t5/arcgis-geostatistical-analyst-questions/why-amp-quot-valid-semivariogram-model-couldn-t-be/m-p/645497#M1450 EricKrause 2011-10-06T13:34:12Z Re: Why "valid semivariogram model couldn't be calculated"? https://community.esri.com/t5/arcgis-geostatistical-analyst-questions/why-amp-quot-valid-semivariogram-model-couldn-t-be/m-p/645498#M1451 <HTML><HEAD></HEAD><BODY><SPAN>Hi Eric,</SPAN><BR /><BR /><SPAN>Thanks for your reply.</SPAN><BR /><BR /><SPAN>I found there was no more trouble calculating variogram and parameters after I reloaded my data and made a new point shapefile.&nbsp; I was able to have the semivariogram modeling section running again.</SPAN><BR /><BR /><SPAN>It was strange, because it the exact same data file (.xls) was imported.&nbsp; </SPAN><BR /><SPAN>However somehow the attribute table showed a bunch of rows with zeros in the troubled one while the attribute table of the latter only showed what I actually have in my .xls file.&nbsp; </SPAN><BR /><SPAN>Semivariogram modeling run with various model setting with the new shape file.</SPAN><BR /><BR /><SPAN>I still don't understand why the troubled shapefile had rows of zeros and the new one did not, but the immediate operational problem seems to be solved.</SPAN><BR /><BR /><SPAN>Thanks again for your reply.</SPAN><BR /><SPAN>Yuko</SPAN></BODY></HTML> Thu, 06 Oct 2011 16:46:33 GMT https://community.esri.com/t5/arcgis-geostatistical-analyst-questions/why-amp-quot-valid-semivariogram-model-couldn-t-be/m-p/645498#M1451 YukoStender 2011-10-06T16:46:33Z Re: Why "valid semivariogram model couldn't be calculated"? https://community.esri.com/t5/arcgis-geostatistical-analyst-questions/why-amp-quot-valid-semivariogram-model-couldn-t-be/m-p/645499#M1452 <HTML><HEAD></HEAD><BODY><SPAN>Good to hear.&nbsp; Without knowing the exact problem, I can't say for sure, but this has likely been fixed since 9.3.</SPAN></BODY></HTML> Thu, 06 Oct 2011 16:50:18 GMT https://community.esri.com/t5/arcgis-geostatistical-analyst-questions/why-amp-quot-valid-semivariogram-model-couldn-t-be/m-p/645499#M1452 EricKrause 2011-10-06T16:50:18Z