Latest Contributions by ColinMacLeod

‎10-24-2016

Hi Dan, That would be perfect. Thank for flagging it up. I'm happy to provide any required info on data sets, the exact process that generated the bug etc if that will help. All the best, Colin

‎10-22-2016

Hi Dan, Thanks for the quick reply. All the requirements you mentioned were checked and double-checked (since, as you suggest, these are usually the source of problems with this tool), but the problem was not caused by any of these. In addition, it's not caused by missing values as all the rasters being used had values for all cells, and the same data sets work with the same tool in ArcGIS 10.3. In terms of reporting this bug with ArcGIS 10.4, part of the problem is that: A. I'm not based on the USA (which means that everything has to go through the regional distributor), and B. Since I was training other people on their own computers from their organisation, it seems I cannot easily report it as I don't have ArcGIS support myself. This is not a problem for me as all I want to do is to be able to report the problem I came across with this tool (as well as providing sample data sets etc) so that ESRI can hopefully do something about it for other users (rather than looking for support as such). It seems odd that there isn't a simple online big reporting system for ArcGIS, like there is for QGIS and other software. Thanks again for taking the time to reply. All the best, Colin PS The work around I noted works with the same data sets, it's just that it would mean potentially having to notify and re-train rather a lot of people around the world for what has become a standard analytical process for marine biologists.

‎10-21-2016

When doing a training session today for a group of marine biologists, it became clear that the Sample tool (SPATIAL ANALYST TOOLS> EXTRACTION> SAMPLE) in the latest version of ArcGIS For Desktop (10.4 - downloaded and installed by the participants this week) has a bug in it which means that when you use one raster data layer to extract values from other raster data layers, it populates some data rows with the value -9999. Other values appear to be interpolated with values that are clearly artefacts of the extraction process as they generate impossible values (e.g. negative values for raster cell values of Slope). This was only a problem with people who were using ArcGIS 10.4 and not those using ArcGIS 10.3 or 10.2. (or indeed 9.3), and occurred on every machine running this version of ArcGIS. It also occurred every time the Sample tool was used with and with multiple different data sets. While there is a work around by turning the raster data layer into a point data layer and then using the Extract Multi Values To Points tool (SPATIAL ANALYST TOOLS> EXTRACTION> EXTRACT MULTI VALUE TO POINTS), this issue means that the standard protocols used to analyse marine biological data when producing species distribution models (SDMs) no longer function as they should. Worse than this, this problem doesn't return an error message, but rather generates artefacts within the resulting data set without any warning meaning it is all too easy for people to assume that the data set created by the tool is reliable when it isn't, and since SDMs are commonly used to make important management and conservation decisions, this has serious real-world implications. My question is this: Is there anywhere that such bugs can be reported so they can be fixed ASAP? At the moment, there is a lot of pressure to shift across to open source alternatives to ArcGIS (such as QGIS), and suddenly encountering situations where previously good tools in ArcGIS no longer function as they should and instead produce data sets with serious, but hard to detect, artefacts, means that most of those in the training session were left feeling they would be better off using QGIS rather than ArcGIS because the appropriate tools in QGIS worked as they should without generating such artefacts (and without having to use awkward, non-standard, work-arounds). It doesn't help that there appears to be no standard protocol for reporting such bugs, and so no way of providing re-assurance as to when it it might be sorted. Any feedback on what do to about such situations would be gratefully appreciated as I was left at a loss as to what to tell the people I was meant to be training.

‎06-05-2012

Hi Smkruzik, Thanks for pointing me in the direction of that great little Add In. It works perfectly for what I am needing to to (in this case it is identify the areas of sea that are surveyed from given land-based surey sites). There wasn't even too much fiddling around to get the exact outputs that I needed. I can see it being used quite a lot by ecologists (my field of study), even though its designed for working with Wireless coverages, as this is the type of thing we need to do quite often. Thanks again. All the best, Colin

‎06-05-2012

Hi All, I am looking to create wedge-shaped buffers around a series of points in a point data layer. Basically these wedges need to be sections of a circle with a user-defined (possibly from fields in the attribute table of the point data layer?) start bearing, end bearing and radius, where the original point is situated at the tip of the wedge. This is to represent a surveyed section of sea from a static survey point. Looking for a solution to this I found the following link from an old ArcGIS forum: http://forums.esri.com/Thread.asp?c=93&f=983&t=238219. This provided the code pasted below for doing this. However, I'm having trouble using this code and can't quite work out how best to load this into ArcGIS and what bits I need to customise/change for my specific computer/settings. I think this is also written for ArcGIS 9.3, while I am using ArcGIS 10.0. If it is relevant, the computer I am trying to use this on is running 64 bit Windows 7. Any suggestions of how to use this code, or of any other/better ways to create wedge-shaped buffers would be greatly appreciated. All the best, Colin Code from old ArcGIS forum: import win32com.client import math, os, os.path from win32com.client import Dispatch GP = win32com.client.Dispatch("esriGeoprocessing.GpDispatch.1") GP.SetProduct("ArcInfo") GP.workspace = "C:\\temp\\" #The function that makes the wedge-shaped buffer def MakeWedge(point, radius): cArray = GP.CreateObject("Array") p0_x = point[0] p0_y = point[1] p1_x = p0_x + radius p1_y = p0_y center = GP.CreateObject("Point") center.id=361 center.x=p0_x center.y=p0_y cArray.add(center) del center #Specify the starting and ending radians - starts at East and goes counterclockwise for i in range(0, 91): cPoint = GP.CreateObject("Point") p2_x = p0_x + math.cos(math.radians(i))*radius p2_y = p1_y + math.sin(math.radians(i))*radius cPoint.id = i cPoint.x = p2_x cPoint.y = p2_y cArray.add(cPoint) del cPoint return cArray try: outfc = "wedges_80km.shp" GP.CreateFeatureclass(os.path.dirname(outfc), os.path.basename(outfc), "POLYGON") except: for i in range(0, GP.MessageCount-1): print str(i+1)+':\t'+GP.GetMessages(i)+'\n' try: rows = GP.SearchCursor("anop_spm.shp") #Reset the cursor to the top. row = rows.Next() #Loop through each record in the shapefile while row: long = row.GetValue("LONGITUDE") lat = row.GetValue("LATITUDE") radius = 80000 cur = GP.InsertCursor(outfc) feat = cur.NewRow() #call the function MakeWedge feat.shape = MakeWedge((long, lat), radius) cur.InsertRow(feat) #go to next record in shapefile row = rows.Next() except: for i in range(0, GP.MessageCount-1): print str(i+1)+':\t'+GP.GetMessages(i)+'\n' del GP

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Latest Contributions by ColinMacLeod

Re: How to report bug with Sample tool generating serious, but hard to detect, artefacts in the resulting data sets in latest version of ArcGIS For Desktop 10.4

Re: How to report bug with Sample tool generating serious, but hard to detect, artefacts in the resulting data sets in latest version of ArcGIS For Desktop 10.4

How to report bug with Sample tool generating serious, but hard to detect, artefacts in the resulting data sets in latest version of ArcGIS For Desktop 10.4

Re: Creating Wedge-Shaped Buffers

Creating Wedge-Shaped Buffers