Latest Contributions by JamalNUMAN

No argument there.  But sometimes the coder has a different understanding of the references they are using than do other readers.  Thus, as documentation of the software, the developer can do very well by describing how they interpreted the equations and implemented in them in the software.  This closes the loop from equation to software back to equation.  Furthermore, by not forcing software users to reference the literature (which often is academic papers not freely available), this makes explicit documentation available to all users, not just the privileged ones with good library access. A recent (nice) example of the value of explicit documentation compared to a mere reference appears at on the StackExchange GIS Q&A site, where a user of open source GIS software found a problem not by testing the software, but by seeing something strange in the documentation (which, because this is OSS, includes the code itself, which is not an option with ArcGIS).  The code was based on good references but mis-interpreted them (and made a few additional mistakes along the way...). I, for one, have appreciated the accessibility of the Python source code in some of the ArcToolboxes, because it goes a long way to showing that these tools are doing what I expect and are doing it correctly.  Otherwise, when working on important projects (and all projects for clients are important!), I have to test the software extensively, because the documentation tends to be non-technical and vague. This is exactly what I needed to know. Including the equations used in the computation is core issue in my opinion. This lets know where we are exactly and based on what the results were computed. Indicating the reference without full details on what exactly have been implemented (particularly where there are definite equations) doesn�??t help the user to be confident about the entire process. Best Jamal ... View more

Jamal It is often better to cite a reference rather than copy from it. This will give you more insight into the inner workings and assumptions around these equations. Which is what we have done for IDW and Kernel Density. Steve Many thanks Steve. best Jamal ... View more

Jamal A search would have led you to a thread Dan participated in 7 years ago, viz., http://forums.esri.com/Thread.asp?c=93&f=995&t=176542 What are the problems that you are seeing? Steve Many thanks Steve for the answer. This is quite helpful. Just I was trying to calculate some values manually applying the equation I�??ve provided in my previous post and got confused about some results. I wanted to make sure about the math used in the ArcGIS to calculate the IDW. I�??m wondering why ESRI doesn�??t include on the help the math they use in such calculations. Another issue that I�??m confronting for the time being is the equation used to calculate the kernel density. How could I obtain the formula used in the such computations? Best Jamal ... View more

ESRI generally doesn't post the equations that they use, but may give reference to cited papers and/or books.  You can be assured that the IDW equation implemented is not of their own making but has a long history of implementation. thanks for the contribution. I tested the result of the IDW and got confused about some resulted values. just i wanted to know if the equation used the same as the one i posted. best Jamal ... View more

Jamal, Please send a screenshot of 'B' layer properties so I can see the extent values.  Please do the same for Elevation.  What happens if you add Elevation to a blank map, then add B to it?  Does B overlay Elevation?  If layer B has the same extent values as layer A that you uploaded to this forum, that would explain the issue.  You can't add two rasters together if they don't line up with one another. Eric Thanks a million! My issue is solved. The problem that the created random layer is not lined up with the elevation raster (as you have advised)! I have to set the extent of the �??random raster�?� to be the same as the elevation raster! Now it is working! Appreciated Jamal [ATTACH=CONFIG]15050[/ATTACH] ... View more

try sending your output to a folder rather than a geodatabase also ensure that both files have the same projection Many thanks. Quite frustrating. I set the output to be in a folder, [ATTACH=CONFIG]15046[/ATTACH] I make the two raster on the same coordinate system [ATTACH=CONFIG]15049[/ATTACH] But still the error is there!!!! [ATTACH=CONFIG]15047[/ATTACH] What might be further there? it remains to say that the B raster is derived from the "create random raster", does this matter? [ATTACH=CONFIG]15048[/ATTACH] ... View more

First, you have to tell me what you mean by "not working".  Is there an error?  Is the output wrong?  Have you tried running the Plus tool instead?  Eric Many thanks Eric for the prompt answers. please, have a look on the sort of errors i got on the screenshots below [ATTACH=CONFIG]15001[/ATTACH], [ATTACH=CONFIG]15002[/ATTACH] best Jamal ... View more

Dan, The link is working for me for some reason...That is how I knew his syntax was correct. Eric then could you guess why it is not working Eric? I've attached the two raster in my previous post. thanks jamal ... View more

Jamal when I click on the link in your initial thread, that is error message I got.  Usually you have images in your threads but not this time. Sorry about that. I�??m attaching the screenshot to this post. Many thanks for the help. [ATTACH=CONFIG]14996[/ATTACH] I couldn't attach both rasters as the size of one of them is more than 2MB. however, the link below might work: http://www.mediafire.com/?pk6tp1n5zomd3ho Best Jamal ... View more

invalid link error Thanks Dan. but why it is invalid? ... View more

Yes, it is valid for feature classes since they use ObjectID too.  For additional details on geodatabase limits you can review File geodatabase size and name limits Many Thanks Eric. this is quite useful. best Jamal ... View more