Latest Contributions by ChrisDonohue__GISP

I think Dan Patterson is on to the reason - the in-line variable substitution is including the path besides the filename, so thus too many characters.  As suggested in the links Dan posted, the Parse Path tool in Modelbuilder  can be used to separate out the name from the path. Parse Path—Help | ArcGIS for Desktop Chris Donohue, GISP ... View more

Another idea: Besides Viewshed, look into Visibility (Spatial Analyst).  I have not used this tool, but it seems to have much of the functionality of Viewshed but with some added functions.  Using an analysis type set to Frequency may be the way to go. ArcGIS Help (10.2, 10.2.1, and 10.2.2) Chris Donohue, GISP ... View more

I'd start with the suggestion by Darren Wiens, and then consider using Modelbuilder (or Python) to iterate a Viewshed on each potential point (this may take several hours of run time), then compare the results. Some thoughts/questions: If you have not done a Viewshed before, I would do some trial runs to get a feel for it. If you can employ a tower, you will need to know the height for the OFFSETA (attribute field) It will probably be worthwhile to employ a RADIUS2 value (attribute field) to exclude distant cells outside your area of interest (this will help reduce processing time).  For the same reason, it may be useful to employ a AZIMUTH1 and AZIMUTH2 (attribute fields) if your observation point is to one side of your buffered area. The Curvature and Refraction corrections could get interesting, as they are designed for light.  How does your radio signal propagate?  Is it line-of-sight or does it go further? Does the Repeater receive signals from another radio source?  Would it be limited in placement by where it could receive the signals to repeat? For best results a complete DEM will be needed.  I mention this as your example seems to be missing some portions of the DEM where there is a trail buffer. ArcGIS Help (10.2, 10.2.1, and 10.2.2) Chris Donohue, GISP ... View more

To add some detail to the suggestion by Kyle Balke Bookmark places—ArcGIS Online Help | ArcGIS An example: By setting a spatial bookmark, you can always return to this spatial extent after working on an mxd.  For example, for this figure I added a bookmark called "layoutview_51,000" so I could remember what to reset the figure to after making edits. Chris Donohue, GISP ... View more

Multiple layouts was a much-liked feature of ArcView 3.x, the predecessor to ArcMap.  However, ArcMap does not support multiple layouts.  There has been talk from time to time about ESRI re-implementing this. Meanwhile, one potential workaround in ArcMap to check out is to use Data Drive Pages: ArcGIS Help (10.2, 10.2.1, and 10.2.2) ArcGIS Help (10.2, 10.2.1, and 10.2.2) Chris Donohue, GISP ... View more

To expand on what David Barnes provided, there can be many issues that crop when exporting marker symbols, as they are created from fonts.  I've found this can be a perplexing problem to resolve, as some of the issues/complications are not well known. 1. The fonts are not on the computer that was used to create the marker symbol. Try using the original computer if possible.  ArcGIS (and other programs) install their own specific fonts, so if a marker was made from them, you will need to be on that computer or font substitution will occur.  That's why one can unexpectedly get "Windings" instead of the marker symbols when viewing on a different computer. 2. Embed fonts option and Convert markers to polygons are well worth exploring and can help in many situations (but see 3). 3. Not obvious - some fonts are proprietary, which means there are conditions and restrictions on using them.  What this means is even if you choose the option to "Embed fonts" or to "Convert markers to polygons", the embedding/conversion will not happen if the font is proprietary - the software has been programmed not to allow it.  Instead, it will default to font substitution.  This was explained at an ESRI Conference Technical session (2011?).  Unfortunately, there is no feedback provided to the user on exporting that font substitution was used; the export will finish out with no warning that a change was made. 4.  Insidious - in some cases one can export to pdf and it will look fine on the computer it was created on.  But when you send the pdf to someone else, all they see are the "Windings"  For example, an interstate highway shield will become a non-sensensical winding symbol.  This occurs when the recipients computer does not have the fonts that were used to make the pdf, so their computer does font substitution to allow viewing.  This can be quite embarrassing for GIS folks - an awesome map is produced but the viewers are wondering why the bizarre symbology was used.  And the GIS person who created the pdf has no idea it looks strange, as it looks fine on their computer.  I've seen maps on many government and private web sites where this has been the case.  So the moral of the story is, after exporting a figure, check it on a non-GIS computer if you plan it to be viewed by others. Chris Donohue, GISP ... View more

I don't have the exact answer, but can provide the projection type likely to be used: Equidistant projections preserve distances, but no projection can preserve distances from all points to all other points. Instead, distance can be held true from one point (or a few points) to all other points or along all meridians or parallels. If you will be using your map to find features that are within a certain distance of other features, you should use an equidistant map projection. Source: ArcGIS Desktop Help 9.3 - what is a map projection? Adding Melita Kennedy to this thread. Chris Donohue, GISP ... View more

To state what Melita Kennedy mentioned in a different way, what may be causing the issue is the coordinate system assigned to your shapefile may not be appropriate for what you are trying to do.  When you create the new shapefile, you will need to assign an appropriate projection/coordinate system for it; so far the information you posted suggests that coordinate system is off. To check the coordinate system, right-click on your shapefile while in ArcCatalog.  Select Properties from the pulldown.  Then click on the XY Coordinate System tab and look at the lower window under Current Coordinate System to see what system is in use.  If it says Undefined, that will can be the issue.  If it only has a Geographic Coordinate System (like WGS84) that also could be the issue.  If it is instead a Projected Coordinate System it is likely then that this is not an issue, but it will still depend upon if the chosen projected coordinate system is appropriate. Chris Donohue, GISP ... View more

Some ideas: I wonder if the Snapping Tolerance is set really high?  Or possibly the Tolerance in the feature class when it was first created was set higher than intended? One temporary workaround I've found that sometimes resolves this is to save your work, save ArcMap, then reopen ArcMap.  This seems to work in cases where several dozen edits have already been done and computer seems to essentially run out of memory, which leads to strangeness when editing. If the feature class you are digitizing to resides in a File or Personal Geodatabase, it may help to run the Compact (Data Management) Tool. ArcGIS Help (10.2, 10.2.1, and 10.2.2) Chris Donohue, GISP ... View more

Some ideas: You may have already checked this, but is there any chance the problem directory has restricted characters or spaces in its name or any folder in its path?  This often trips up GIS processes. Some processes will crash if the combination of both the filename and file path exceeds 255 characters.  I've even had some crash when the combination was only 240 characters, which technically should have worked.  One way to test this is to move some of the data to the C: drive into a simple folder (example C:\Model) and then set the outputs also there.  Are you running the model from the Edit Window or as a Tool?   I ask as there was a bug not long ago that would cause models to crash if run as a tool but they would work if run from the Edit window. Can you post a screenshot of your model?  This will help folks get a better sense of what you are trying to achieve and how the processes are connected. Chris Donohue, GISP ... View more

A question - is your .csv "live-linked" to your existing spatial data or after adding new data you are importing it as if it was a totally new file? Chris Donohue, GISP ... View more

Some questions to help clarify your request: 1.  Which software will be used to display this?  And which version? 2.  Is the Creation time an attribute in a dataset or would it be derived by other means (example:  transaction history)? Chris Donohue, GISP ... View more

I have a question then on List Comprehensions. Using Dan's one-line example, I came up with the variation that fit my data: " ".join([str(i) for i in [ !STRNUM!, !STRNUMSUF!, !STRPREDIR!, !STRNAME!, !STRTYPE!, !STRSUFDIR! ] if i]) So, the question is, does the for i automatically create a List Comprehension as part of using it?  It seems like in this case it does not need to be declared, as it was in your example.  Or is there a different process going on?  I'm assuming the for i is a looping process - is a List Comprehension built into it?  Just curious. Chris Donohue, GISP ... View more

That helps.  But I'm curious about something.  The code as you wrote has more detail and is easier to see the pieces.  However, I see a List and Append that are not visible in the one-liner Dan posted.  I'm assuming Join is accomplishing the same thing, is that correct? Also, the looping in Python is throwing me a bit.  How does Python know to end a loop?  This reminds me of If-Then in other languages, but there is no explicit Then here. Chris Donohue, GISP ... View more

I forget which comedian came up with this adaption of a famous quote on existence: "I think, therefore I am...... I think?"  (unsure)    Chris Donohue, GISP ... View more