Latest Contributions by ChrisDonohue__GISP

To prepare for this exam,  I would recommend researching Spatial Overlay Analysis topics.  Overlay analysis—Help | ArcGIS for Desktop  Also, assuming you are using ArcGIS, I would look at the Geoprocessing tools in the Analysis Tools section of ArcToolbox, as there are several that would work in answering the question you posed (there is more than one way to do this with those tools). Open the tool, then click on the Tool Help button to open a windown with information on what it does.  Note that what tools you have available will vary depending upon what licensing you have. Chris Donohue, GISP ... View more

It is suspicious that the layer does not convert.  Was there an error message that accompanied it when the conversion was attempted? Also, I would check to be certain that both layers have assigned coordinate systems.  It may be that one layer does not have an assigned coordinate system, but visually lines up in ArcMap as the coordinate system is already set for the Data Frame that is being used to view it (the data frame inherits the coordinate system from the first layer brought in).  Chris Donohue, GISP ... View more

One thing that may be contributing to this is the presence of spaces and a potentially restricted character (the dash) in the file paths.  Remedy this for your Flow Direction Grid by adding underscores to Neuer Ordner where there are spaces and just to be safe remove the dash. Check all your other data to see if this is an issue. Raster processes have much more specific file naming conventions than typical GIS files, so this could be what is causing the problem.  Unfortunately, there is not an explicit error that will come up advising the user that spaces and restricted characters are present and therefore causing a problem. Output raster formats and names—ArcGIS Help | ArcGIS Desktop  Chris Donohue, GISP ... View more

I've had similar observations and talked with ESRI Support about it.  Essentially what is going on is that at a scale of less than one to one the software can no longer visually display the linework correctly.  So what is being viewed is not really an accurate depiction. Of course, seeing these apparent slivers (and gaps) can be a bit disconcerting.   Visual review is one way people see issues, so the question then becomes, is the issue real or not? So here is one way to check.  Measure the gap with the Measure Tool.  As mentioned by Micah Babinski the XY Tolerance controls how close linework is to be considered coincident.  If the distance measured turns out to be less than the XY Tolerance, then the linework is coincident, even though way zoomed in it looks like there is a problem. Also, more generally, if one sees issues, check the scale right off the bat.  If it is less than 1:1, realize that what is being displayed may not be an accurate depiction. For more specifics, check out the reply from ESRI Support when I posed similar issues I noticed to them: As per our phone interaction, a map scale past 1:1 is a known limitation of our software because at a scale of 1:1, the screen display is equal to the actual distance of objects on the earth's surface (i.e. an inch on your screen is equal to an inch on the ground). When you go past that scale, it may appear that features are overlapping (when in reality) what you are seeing is the actual software resolution tolerance pushed past it's maximum threshold. In essence, the entire screen is only one point (at a map scale of 1:0), which is why your work flow is producing inaccurate results.  Strangeness - gaps unintentionally created while editing  Chris Donohue, GISP ... View more

Not sure if this is the issue, but I'll throw it out there.  To add to what Duncan Hornby  suggested, what sort of database is the information coming from?  Depending upon which database is being used, one uses different formatting for the field names. Fields To specify a field in an SQL expression, provide a delimiter if the field name would otherwise be ambiguous, such as if it were the same as an SQL reserved keyword. Since there are many reserved keywords, and new ones can be added in subsequent releases, a good practice is to always enclose a field name with a delimiter. Field name delimiters differ from DBMS to DBMS. If you're querying any file-based data, such as a file geodatabase, ArcSDE geodatabase data, or data in an ArcIMS feature class or image service sublayer, you can enclose field names in double quotes: "AREA" If you're querying personal geodatabase data, you can enclose fields in square brackets: [AREA] For personal geodatabase raster datasets, you should enclose field names in double quotes: "AREA" For File geodatabase data you can enclose your field names in double quotes, but it's generally not needed. AREA Source:  SQL reference for query expressions used in ArcGIS—Help | ArcGIS for Desktop  Also, one Modelbuilder troubleshooting suggestion.  Open the model in Edit Mode, Validate it, then run it (still in Edit Mode) by manually activating each step (Right-click on box, Run).  Hover over each completed box (has shadow) to see the values it produced.  This can help track down which step is failing. Chris Donohue, GISP ... View more

Two immediate potential problems to resolve are the space in the path name at "ben poole", and the combined length of the grid filename and its path being potentially over 128 characters at any stage in the processing.  Since the process is using an ESRI GRID, it has to meet very specific file and path-naming conventions, which are much more constrained than for other data types.  I'd start by fixing these, as it often seems that these grid issues also spawn other unrelated errors.  Esri Grid format The name of an Esri Grid format raster has more specific restrictions: The maximum number of characters is 13. It cannot have spaces. It cannot use special characters other than underscore ( "_" ). For tools that output a Grid Stack, the stack name cannot have more than 9 characters. The total length of the name for a Grid and its path cannot be more than 128 characters. Output raster formats and names—ArcGIS Help | ArcGIS Desktop  Bear in mind that these constraints applies to the folder names also.  Having just one space in a folder can cause things to go awry.  Note that their is no specific error that will come up alerting the user that the issue is due to a space being present. Also - not a hard and fast requirement, but can help - stay away from the /Users/username structure if possible.  Try to use a very short, direct path to the data, like C:\Data\Model or such.  In theory it should not matter, but in reality sometimes that can be the difference between an operating process and one that throws errors. Chris Donohue, GISP ... View more

A common reason for getting the "no route" message is a disconnect in the network.  If you have not already, I would run topology on your source linework to see if there are any disconnects.  Note that there can be tiny disconnects present which will not be visible yet will disrupt the connectivity.  One option before running regular topology is to use the following ArcGIS Addon (originally designed for street linework) to quickly check your rail linework to find gaps. Topology Check Python AddIn (6/30/17)  If this is not the culprit, there are several settings that may potentially be causing the issue.  Keep in mind that Network Analyst is often used in the context of street routing, so when it is used for other systems like rail one has to review the settings in their context to see if they will apply in a similarly fashion.  I have not done rail networks, so don't know the particulars, but I suspect some review will be needed of the settings (and translation from street concepts to rail concepts) to ensure the behavior will be as expected. Creating a network dataset—Help | ArcGIS for Desktop  Understanding connectivity—Help | ArcGIS for Desktop  Offhand, I don't think the turns themselves are the issue, but am not certain of that (I have not used them that extensively). Here's some information on turns: Turns in the network dataset—Help | ArcGIS for Desktop  Chris Donohue, GISP ... View more

If you do find that data cleanup will be needed, consider downloading and installing this plug-in by GeoNet contributor timw1984  as a handy means to detect issues in your street linework. Topology Check Python AddIn (6/30/17)  Chris Donohue, GISP ... View more

My first guess would be as Dan Patterson surmised, that the analysis was run with different settings.  In particular, were the Polygon Generation settings the same between both runs?  The Polygon Type and Trim Polygon settings can make a large difference in the output. As  Joe Borgione suggested, there are is some information available on how to work with OSM data.  I don't know quite so much about this aspect, but this gentleman at Esri does, so let me tag him in case he can offer some more insight:  Jay Sandhu  If connectivity in the network has come up as an issue, consider running Topology on the source data used to create the network dataset (if you have that available) to find any disconnects.  Note that it is common to run into disconnects in street data, as often the data was created with CAD, which does not snap the line ends to be coincident. In terms of building a functional network dataset, this Esri link is very helpful for the workflow and the various aspects one has to consider: Creating a network dataset—Help | ArcGIS for Desktop  Chris Donohue, GISP ... View more

SDE can be pretty complex.  Some questions for you on the issue to help responders: Do you have SDE Administrator rights?  If not, what level of permissions/privileges do you have currently?     Privileges for geodatabases in SQL Server—Help | ArcGIS Desktop    Privileges for geodatabases in Oracle—Help | ArcGIS Desktop    Error: No editable layers—Help | ArcGIS for Desktop What database is SDE tied to?  SQL Server?  Oracle?  other?  Also, what version? What version of ArcGIS are you using? Chris Donohue, GISP ... View more

The number of questions depends upon which exam you signed up for: 10.3 exam Number of questions: 95 https://www.esri.com/training/catalog/576621cbecbdb2fa0984b16a/  10.5 exam Number of questions: 80 https://www.esri.com/training/catalog/582b66ac146072a52e8e558a/  Numerical scores will not be given. Candidates will receive a Score Report which illustrates a section level analysis of the candidate’s exam performance. https://www.esri.com/training/certification-take-exam/  I'm tempted to say the passing score is 80% - at least that what I recall from when I took it a few years ago - but I don't see any current statement to that extent. Chris Donohue, GISP ... View more

Large PDF filesizes can definitely be an issue, as many clients/customers require a PDF that is not huge, so trying to reduce the filesize is an interesting challenge.  There are several easy ways to do the reduction, but the trade-off in quality can be a concern. It is important before starting a reduction to decide what level of quality will be needed for the final product. Then, the place to start in the quest to reduce filesize is the export settings in ArcMap.  There are quite a few, so I'd experiment with them all to see what the tradeoffs are.  When doing File, Export Map, be sure to click on the triangle by the word Options at the bottom of the export window to reveal the settings tabs. Exporting to PDF—Help | ArcGIS for Desktop  If that doesn't go far enough, consider running a file reduction process in Adobe.  There are several processes available which will "flatten" a file, but at at cost of quality.  Also, most of the processes will greatly limit the ability of downstream users to edit the result, as many of the vectors will be rasterized.  Depending upon which Adobe product you have, these processes have different names, so one may have to poke around to find what the process is called. Optimizing PDFs in Adobe Acrobat Pro  https://acrobatusers.com/tutorials/reducing-file-size  Lastly, in some circumstances one can vastly reduce the filesize by making some adjustments to the layer display in ArcMap.  Specifically, if one forgoes using transparency in the layers in the Table of Contents, one can vastly reduce the filesize.  The ArcMap export process greatly increased filesize of transparent layers by automatically rasterizing the topmost transparent layer and all layers below them in the Table of Contents.  So undo any transparency, or if the transparency is needed, see if the layer can be moved down in the table of contents.  Doing so often results in quite a surprising reduction in filesize. Chris Donohue, GISP ... View more

Adding 911 GIS for greater exposure. Chris Donohue, GISP ... View more