Spline interpolation operation fail ArcGIS 10

[KarenBlakey]

Hi I am hoping someone can help me.  I am having problems running the spline interpolation tool in ArcGIS 10.  I have service pack 5 installed.  This is an academic exercise and I feel as though I have followed the instructions carefully.  I have managed to run the IDW and the kriging interpolation operations with no problem.  I cant understand why the spline operation fails every time.  Any help would be appreciated.  Apologies if I have left out important information in my description of the problem.  I am very inexperienced in this field of work.  Please let me know if you require any further information.  I have set the environment setting as instructed.  Many thanks Karen

[MarcoBoeringa]

Karen,

The interpolation tools in Spatial Analyst are really unsuited for anything but the most preliminary assessment. You really should start to delve into Geostatistical Analyst for anything requiring "scientific" or academic grounding, as Geostatistical Analyst offers far more and better tools, including cross validation and exploratory data analysis.

These tools in Geostatistical Analyst will help you in finding out what might be "wrong" with your dataset, and what needs to be done to make the dataset suitable for interpolation (if at all possible!).

Common issues I often see:

- To small dataset (like trying to interpolate 7 points or so)
- Non-continuous dataset / phenomenon measured, which violates the basic principal of continuity underlying the whole "interpolation" concept. Sometimes, you really shouldn't be interpolating data, but using other (statistical) methods to process your data, like using a program like SPSS or R. Quite often, people cling to the idea of "I must interpolate this data!", while their data may in fact be unsuitable...
- Non-normal distributed data. Data may need to be transformed, e.g. by taking the log.

Geostatistical Analyst, with its Exploratory Data Analysis tools, will help you in finding out if your dataset is suitable for interpolation, and help with possible transformation or other settings needing to be made before or during interpolation.

You may find the document by Gregg Babish, that I linked in the below thread post, useful as a basis for better understanding interpolation techniques:

http://forums.arcgis.com/threads/95588-Simple-Kriging-question-please-help!!?p=339687&viewfull=1#pos...

[KarenBlakey]

Karen,

The interpolation tools in Spatial Analyst are really unsuited for anything but the most preliminary assessment. You really should start to delve into Geostatistical Analyst for anything requiring "scientific" or academic grounding, as Geostatistical Analyst offers far more and better tools, including cross validation and exploratory data analysis.

These tools in Geostatistical Analyst will help you in finding out what might be "wrong" with your dataset, and what needs to be done to make the dataset suitable for interpolation (if at all possible!).

Common issues I often see:

- To small dataset (like trying to interpolate 7 points or so)
- Non-continuous dataset / phenomenon measured, which violates the basic principal of continuity underlying the whole "interpolation" concept. Sometimes, you really shouldn't be interpolating data, but using other (statistical) methods to process your data, like using a program like SPSS or R. Quite often, people cling to the idea of "I must interpolate this data!", while their data may in fact be unsuitable...
- Non-normal distributed data. Data may need to be transformed, e.g. by taking the log.

Geostatistical Analyst, with its Exploratory Data Analysis tools, will help you in finding out if your dataset is suitable for interpolation, and help with possible transformation or other settings needing to be made before or during interpolation.

You may find the document by Gregg Babish, that I linked in the below thread post, useful as a basis for better understanding interpolation techniques:

http://forums.arcgis.com/threads/95588-Simple-Kriging-question-please-help!!?p=339687&viewfull=1#pos...

Hi mboeringa2010,
Thank you so much for such a comprehensive reply and the links for further reading.  The problem I have is that this is part of an acacademic exercise so I would assume that the given I have been asked to run the Spline operation, the data are set up for this.  I was given specific instruction to set the environment etc.  So surely the lecturers would not be setting me something that is unsuitable or inappropriate?  Indeed I hope not, I am trying to learn about GIS not be put off it altogether :-O. 

I have read another forum thread where people appear to have been having similar problems with running the Spline with boundaries operation.  One of the replies suggested that java script could be causing a problem.  I am not that confident on playing around with the set-up of my laptop but I would feelOK following step by step instructions. 

Once again, I really appreciate your logical and helpful response.  I will look at the link you suggest and will see if it sheds any light. Many thanks, Karen

[MarcoBoeringa]

Hi mboeringa2010,
Thank you so much for such a comprehensive reply and the links for further reading.  The problem I have is that this is part of an acacademic exercise so I would assume that the given I have been asked to run the Spline operation, the data are set up for this.  I was given specific instruction to set the environment etc.  So surely the lecturers would not be setting me something that is unsuitable or inappropriate?  Indeed I hope not, I am trying to learn about GIS not be put off it altogether :-O.

Maybe it would be best to contact your tutors / teachers who gave you this material. Alternatively, if you post the data and the settings you applied here on the forums as an attachment to a post, I or someone else can have a look at it and try to replicate the issue.

I have read another forum thread where people appear to have been having similar problems with running the Spline with boundaries operation.  One of the replies suggested that java script could be causing a problem.  I am not that confident on playing around with the set-up of my laptop but I would feelOK following step by step instructions.

I doubt if Javascript has anything to do with it. The scripting languages in ArcGIS for Desktop are VBScript and Python, not Javascript.

Once again, I really appreciate your logical and helpful response.  I will look at the link you suggest and will see if it sheds any light. Many thanks, Karen

It won't give you an answer as to why ArcGIS for Desktop fails at the Spline operation, as it is a generic document dealing with Geostatistics and interpolations, not with ArcGIS. It will give you a better insight and understanding of the basis of interpolation methods, which will help in understanding ArcGIS's options for this.

[KarenBlakey]

Hello again, I am hoping I have correctly attached the data related to the exercise to this message.  I will try again if I haven't.  I have been in touch with my tutors and sent screen prints and they do not know why the spline operation fails.  I feel as though I have followed all of the instructions and I am not trying to cheat here, I am just trying to find out why it wont work.  As I have ArcGIS version 10 I produced my own merged shape file containing all the point files.  I then successfully produced the thiessen polygon shape file.  And as I said, I also had no problem running the krigin interpolation and the IDW too.  It is just a problem with the spleen.  I have also attached a screen print of the error message and the legends for the Kriging and IDW raster files. 

I am really pleased you have sent me the link because I definitely need to have a better understanding of the fundamentals.  Many thanks for your help.  VBW, Karen

[KarenBlakey]

I have managed to run it.  Hoorah.  The instructions state that in environments you set the extent 'same as display'.  Instead I set the extent to one of the raster layers that I produced successfully.  It worked.  Thank you for your feedback.  At least I have got your link to look over more of the fundamental building blocks of this science.  😄