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I tried the simple kriging model as you suggested, but can I assume that the mean/trend is known and constant for my data? Thanks again! Kirsten This is something only you can answer with your expert and field knowledge of the terrain / research site. There are statistical tools in Geostatistical Analyst that will tell you whether some assumptions are more or less reasonable or appropriate based on statistics, but in the end it is you who needs to decide which models or assumptions are best for your data.
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07-11-2012
10:39 PM
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Are you using Background Processing? Processing in the background means sending the features you want to process over to another process and then getting a result back. Because its another process we have to persist them to disk for ArcMap to read them on the way back. Why o why didn't ESRI document this crucial factor in getting in_memory to work in the Help file??? I really can not find it in the main in_memory Help topic. This issue regarding background processing should be added under the "The following considerations must be made in deciding to write output to the in-memory workspace" text line. I have been struggling with this issue too.
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06-20-2012
06:12 AM
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You may also wish to have a look at this recent thread, as it discusses issues and solutions regarding 32-bit / 64 bit memory space and Python/ArcGIS too: Large Dictionary Compression? http://forums.arcgis.com/threads/58348-Large-Dictionary-Compression?highlight=32+bit+stream+network Marco
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06-20-2012
06:05 AM
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Some geoprocessing tools cannot take in_memory datasets as inputs/outputs. Yes, I was aware of that possibility. However, I still can not get the Con (conditional) tool of Spatial Analyst to accept the set extent on the "env" environment object, despite it being listed among the accepted "Environments" in the ArcGIS Desktop 10 Help. I clearly see it being set while debugging, as the correct extent with correct XMin, YMin, XMax, YMax is visible in PyScripter, but as soon as I use the Con tool in the script, the output is using the input raster extent instead of the set extent of the environment settings. The mask setting is properly used as long as the dataset is physically written to disk, as I wrote before.
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06-09-2012
05:31 AM
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I don't know if it has anything to do with it, but I now noticed that only when I specifically write the mask file to disk, it is properly used as a Mask environment setting. I had been using the "in_memory" option for storing the polygon representing the mask instead of physically writing it to disk. Maybe there is an undocumented limitation with using "in_memory" datasets as environment settings for analysis, and you can't use them for that directly...? Anyone else experience this issue?
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06-03-2012
08:57 AM
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Hi all, I am trying to set some environment settings through Python. When I look in Debug mode in the PyScripter IDE at all environment variables (launched from ArcMap by right clicking the script and choosing "Debug"), I see my Extent and Mask setting correctly being applied to the GPEnvironment "env" object, the correct coordinates and path to the mask file are visible. However, when I look at the final result of a Spatial Analyst "Con" conditional operation, the resulting raster doesn't honor the Mask set for the environment in the script in which the Con command is used. According to the Desktop Help, the Con command should honor the Mask setting... In addition, the extent, when viewed in PyScripter debugging mode, of the resulting raster, is incorrect too. The extent is the extent of the original raster, not the extent set dynamically in the Python code of the script. Any clues as to why this is happening? ArcGIS 10 SP4 by the way. Marco
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06-03-2012
05:19 AM
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Did you check out the Spatial Analyst extension? Hi Luke, Just before you posted, I found a similar topic regarding licensing of ArcGIS levels and extensions in the Desktop 10 Help: Accessing licenses and extensions in Python http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//002z0000000z000000 Like you suggested, I did not check out the Spatial Analyst extension, as I wasn't aware I needed to do this. I now changed the code with help of the examples, and it works properly! I can see the Raster object listed now in PyScripter's debugging mode and variables window. Very nice and useful. Thanks for the response. Marco
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06-02-2012
01:45 AM
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Hi all, Just starting with Python, I now decided it was time to see if I could get debugging functional in a Python IDE, to ease coding and debugging. Since I couldn't get PythonWin to function as a debugger for ArcGIS, even after specifically setting it as the debugging application in ArcGIS 10's Geoprocessing Options, I decided to download PyScripter instead, as I saw it mentioned on another forum. That works! I could get it launched from ArcGIS by right clicking a script and choosing "Debug". It properly loads and executes and nicely shows all content and properties of the variables and functions used in the script. However, as soon as I use a Spatial Analyst command (which is licenced, and I have run the same script successfully from ArcGIS), the debugger stops at that point stating "The tool is not licensed" as visible in the PyScripter "Python Interpreter" window. Is there anything else I need to do to make an external Python IDE like PyScripter aware of available licenses on extensions like Spatial Analyst? Any specific settings to be made or arcpy modules to import??? Any suggestions welcome! Marco
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06-02-2012
12:18 AM
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Thanks Curtis, this is very useful information, certainly a help for future development with ModelBuilder.
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05-21-2012
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This is the way to do it. It seems elaborate but there is no other way as ModelBuilder accesses those variables accessed with "%" syntax as strings -- not objects. The commas separating arguments is python syntax, there is no way around that. Thanks Curtis, it is appreciated. This is a clear explanation, and I was suspecting something like that. As I am just starting with Python, it is all a bit new to me and getting to know these specific issues and how to handle them, takes time. The way this all works is the the input expression to Calculate Value is interpreted by model builder (variables substituted in) -- and the resulting function is then passed to python literally. This is the same reason that pathnames must be used with Calculate Value like this: def func(r"%mbuilder path variable%") Hope this helps! Could you elaborate a bit more on this specific subject regarding pathnames? I haven't read about it before. And is the "r" before the inline variable a typing error, or does it need to be there?
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05-21-2012
01:14 PM
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The error is in the incorrect usage of Python's "rstrip" command. "rstrip" removes ANY occurrences of the characters in the search string you supply (in your case "_shp") from the right side of the processed string. This is why it is going wrong, since "citiespop_shp" contains an additional "p" character as the ending, and since "p", is part of "_shp", it is also removed from "citiespop", resulting in "citiespo". The removing only stops at the "o" character ("citiespo"), as that is the first character not part of the search string "_shp" Please note that for "rstring", the order of the characters you supply is irrelevant. If you coded: "teststring.rstring("phs_")" the results would be exactly the same, e.g. giving you "citiespo" for the processed basename "citiespop_shp" You will need to use another of Python's string commands to accomplish what you want to do.
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05-20-2012
07:13 AM
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Hi all, For the record: ArcGIS 10.0 SP4. Just getting my feet wet for the first time with more advanced ModelBuilder techniques in combination with Python, I noticed there is a possible issue / bug with the in-line variable substitution in non-English locals. My computer is set to Dutch, and displays "," as the decimal point character. However, if I have a numeric variable with a decimal point in it (in my case the values were Double), think of "1234,56789", the in-line variable substitution leads to a fault as soon as the variable is inserted in a Python function's argument list, as Python uses the comma "," character to separate out different arguments. I saw this issue popping up when I tried using two Double variables as arguments in the Calculate Value tool of ModelBuilder. See the attached screenshots. The first screenshot shows the original Python code I inserted in the Calculate Value tool. This code returned the error seen in screenshot 2. Notice it clearly states that the "getMBRsqrt" function I defined "takes exactly 2 arguments (4 given)" while 4 given!. Also look at the string of numbers in the red lettered error description. It shows the two variables I passed also being separated by the decimal comma of the values themselves, causing 4 "pseudo arguments" to be passed over to the function, instead of two numbers using decimal points. This is of course wrong, and leads to the fault, as my function only accepts two arguments and must have the decimal values / doubles passed over. Only when I elaborately changed the function, and passed the variables as strings, converting them back to numbers, could I run it. See screenshot 3 for the modified code in the Calculate Value tool that did run properly. Before I needlessly start reporting this to ESRI, can someone else confirm this issue? I tried finding it in the list of fixed issues for SP5, but no such issue seems listed for fixing. Marco
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05-19-2012
02:47 AM
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Getting good at geostatistical modeling requires study, practice, and often a bit of luck. X2. I think many people underestimate the need to delve in these kind of subjects, whether it's geostatistical or plain statistical modelling on numbers. There is a lot going wrong in practice, and unfortunately also many datasets not only misinterpreted, but often under-used because people don't know what to do with it to get interpretable results. If you read the help and decide you want more information, a colleague published a book last year on performing spatial statistics (and geostatistics) in ArcGIS: http://esripress.esri.com/display/index.cfm?fuseaction=display&websiteID=194 Don't forget this small but helpful introductory whitepaper by the same author: http://www.esri.com/library/whitepapers/pdfs/intro-modeling.pdf
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05-16-2012
01:39 PM
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Can't answer your question as I haven't tried what you are attempting, and you probably already read it, but this ESRI PDF gives some more details, see point 5... Maybe there is a limit to the number or Feature Datasets open for editing (just 1 allowed??). E.g. you are not allowed to make two Feature Classes in two different Feature Datasets editable, but are allowed to edit one Stand-alone (not in Feature Dataset) Feature Class, and one residing in a Feature Dataset...? Just guessing here.
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05-12-2012
11:34 AM
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OK, I now discovered more or less what and where is actually going on. While ArcMap only shows a progress bar for a few minutes, the unaccounted time afterwards is spend writing classic ESRI grid format files in the Windows user profile's Temp directory. I can see ESRI grid files being build up (file size increases) in cryptically named subfolders. Seems the processing needed for a fill are far from over when ArcMap stops showing progress. Frustrating. It is still unclear exactly what is going on. I know the Help states Fill is the equivalent of a number of tools combined. "The Fill tool uses the equivalents of several tools, such as Focal Flow, Flow Direction, Sink, Watershed, and Zonal Fill, to locate and fill sinks.", so I wonder if ArcMap is just combining the outputs of these processes, or is really "filling up" / replacing sinks with hydrologically corrected DEM values. Whatever, I am glad it is now doing it on an external SSD, and not my harddisk, because it is literally writing Gigabytes of grid data on end to the Temp and subsequently removing files again.
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05-12-2012
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