Latest Contributions by ChrisDonohue__GISP

Adding: Addressing  Chris Donohue, GISP ... View more

Question - is the ability to affect the point data constrained by being in a Versioned environment (Enterprise Geodatabase/SDE)? Also, you may already know this, but I will toss this out in case it helps: To add to what Dan Patterson  proposed, if the goal is to end up specifically with Python Code to do this process and you it can already be manually accomplished with geoprocessing tools without any issues, there are several ways to figure out the equivalent Python coding. One possibility is to run through each Geoprocessing tool you would use to do this process manually, look at the sample Python Code for that tool, then put all the code together.  For example, Spatial Join (Analysis) has some example code in the Tool Help that one could modify to match your data ArcGIS Help (10.2, 10.2.1, and 10.2.2).  Even easier, one could also just run your process with the tool manually, then dump out a code snippet for that process after it was run manually by checking the Geoprocessing Results and capturing a Python Snippet.  The advantage of this is that the exact files used are already coded in as the inputs and outputs.  Here's an example that shows how to extract the Python Snippet used in a tool run: Another option is to string together all the processes in Modelbuilder, then dump out the entire Python code from that after getting it all to work.  One caveat here, though - there are some processes in Modelbuilder that don't work outside Modelbuilder (i.e. they don't translate to Python). Exporting a model to a Python script—Help | ArcGIS for Desktop  Chris Donohue, GISP ... View more

Can you draw a picture of what you are trying to achieve?  It may be possible to do this with Network Analysis, but I'm not entirely clear on what you are trying to accomplish. For example, is the freeway segment being treated as a linear "starting point" and you want to find the maximum distance one could travel away from any part of that segment in a set amount of time?  If so, one approach would be derive points from all intersections of the "starting point segment" and roads contacting it, then run a Service Area for each point, then combine them.  This could be set up in Modelbuilder using an Iterator or programmed in Python to automatically run all the possibilities and then combine them into the result. Chris Donohue, GISP ... View more

Questions: Does "GP" stand for Geoprocessing Tool? Is it a requirement that this be done with ArcHydro?  If not, if you have access to the Spatial Analyst extension it can be done there.  First, one would develop the overall watershed model first for the potential area of effect (i.e. start with a Digital Elevation Model and run Fill, Flow Direction, Flow Accumulation, etc).   Then one would specifically derive the watershed for your leak point using Watershed (Spatial Analysis Toolbox), with the leak point being as the pour point. How To: Create a watershed model using the Hydrology toolset  How Watershed works—Help | ArcGIS for Desktop Chris Donohue, GISP ... View more

I'm not sure if things work the same way in ArcGIS Pro, but if it was ArcGIS Desktop one possibility would be to check the Environments Settings to see what Extent is being used.  It appears to be defaulting to the extent of your points. Also, what projection/coordinate system are you using? Chris Donohue, GISP ... View more

There is a Python Code sample in the help section for Interpolate Shape that may be use.  Note that it requires access to the 3D Analyst extension. Interpolate Shape—Help | ArcGIS for Desktop Chris Donohue, GISP ... View more

I'll second what Neil Ayres said - there is not much data, so there won't be much to interpolate with.  Any chance you can get more depth data points?  I suspect the "bulbous" result may be due to many zero points (shoreline) versus the few water depths points, as the many zeroes will result in a higher influence over the final result. Chris Donohue, GISP ... View more

Not to nitpick, but a thalweg is often not the same as a centerline. A thalweg is the lowest point in a waterbody and in a moving waterbody that meanders it will be found on the outside of the curve (not in the center).  Depending upon what your goal is of this analysis, that can throw things a bit if centerline data is used instead of thalweg location data. Thalweg - Wikipedia, the free encyclopedia images source:  Aerial Geologist: Thawing Thalweg EDIT - added images from the link to help folks better visualize the spatial location of a thalweg. Chris Donohue, GISP ... View more

You may not need an iterator - it all depends on how many fields you are adding.  If you are just adding a handful of fields to one file, I would suggest the pragmatic approach of just having several Add Fields functions chained together in a row in Modelbuilder (one after another). Add Field - ArcGIS Help (10.2, 10.2.1, and 10.2.2) How many fields do you need to add? Chris Donohue, GISP ... View more

What  Dan Patterson  is pointing out is that there are several ways to do a split, but without some more details on your part it will be impossible to come up with a solution. For example, which program are you using?   ArcMap?  ArcGIS Pro?  Arcview?  Something else? And what version?  Functionality sometimes changes between versions. If you can provide more information, that would help greatly in troubleshooting this.  This can include not just words, but visual information.  Take a snapshot/screenggrab of the attribute table.  Take a screenshot of the program.  Add them to your post. Chris Donohue, GISP ... View more

There are several possibilities: Given that the file is AutoCAD and most people in the AutoCAD world don't deal with projected data, it is entirely possible it is a "Local" projection - i.e. the CAD operator set the Southwest-most portion of the site to 0,0 and then worked from there. It may be in a commonly-used coordinate system for the Ontario area.  Though the coordinates you posted don't adhere to the best-practice used with established coordinate systems of having the Northings and Eastings values one order of magnitude different so as to allow users to quickly establish which is which from just the numbers should the data header information get lost.  However, just to muddy things up, this best practice is not used by all coordinate systems. I'd look into the available coordinate systems for your province. How To: Identify the spatial reference, projection, or coordinate system of data Also, let me add someone who may know it off the top of his head: Dan Patterson Chris Donohue, GISP ... View more

If your points are North to South, you can do this in a three-step process (or East to West.  However, this won't work for points that "wander"). First, add coordinate values to your point attributes (several methods - here are some, choose one): http://forest.mtu.edu/faculty/hyslop/gis/ArcGISCalculateXY.pdf ArcGIS Pro - Add XY Coordinates—Data Management toolbox | ArcGIS for Desktop If you have XTools (third-party software for ArcGIS), there is an Add XY coordinates function to do this automatically. Second, open the attribute table.  If you don't have a field for the draw order set up yet, create a numeric field.  Then "Sort Ascending" (or "Descending" depending upon where in the world your data is) on the Y Coordinate value column created in the above step, which will arrange your points in North to South order.  (Note - if your data crosses the equator you will need to split the data into two chunks, then recombine after processing). Third, with the attribute table still open and sorted, increment your draw order field using Field Calculator and either VB or Python scripts (your choice - see below): VB - http://www2.fiu.edu/~tardanic/idfield.pdf Python ArcGIS Help 10.1 - scroll way down to the section Accumulative and sequential calculations, then use the code in "Calculate a sequential ID or number based on an interval." Chris Donohue, GISP ... View more

In regards to your last question of getting the actual routes through a network when using the OD Matrix feature, the ESRI help states that this is not possible (at least in version 10.2.1): Tip: The closest facility and OD cost matrix solvers perform very similar analyses; the main difference, however, is in the output and the computation speed. OD cost matrix generates results more quickly but cannot return the true shapes of routes or their driving directions. It is designed to quickly solve large M x N problems and, as a result, does not internally contain the information required to generate route shapes and driving directions. Alternatively, the closest facility solver returns routes and directions but performs the analysis more slowly than the OD cost matrix solver. If you need driving directions or true shapes of routes, use the closest facility solver; otherwise, use the OD cost matrix solver to reduce the computation time. Source:  OD Cost Matrix Analysis - ArcGIS Help (10.2, 10.2.1, and 10.2.2) Chris Donohue, GISP ... View more

I don't have an answer for why this is not adding the layers to the Table of Contents as expected, but wanted to mention something that may trip things up in other regards.  The filename chosen for the rename has a dash in it and spaces, both of which can trip up ESRI GIS processes.  I'd avoid using the dash altogether and use underscores for any spaces. lyr.name = "PROPOSED - site_polygon"  Chris Donohue, GISP ... View more