Latest Contributions by ChrisDonohue__GISP

Dan, Sounds like Canada might be more constrained than the U.S in the use of addresses by marketers.  Here in the States businesses and organizations have fairly free reign to create address lists from whatever sources they can lay their hands on and then send people mail.  You should see all the unsolicited stuff in my mailbox!  Marketers love address databases.  Even the US Post Office will sell address lists for various geographies.  And, like in email, it can be difficult for a person to "opt out" of all the advertising ("paper spam") one gets. Chris Donohue, GISP ... View more

As Robert Scheitlin, GISP mentioned, there is unlikely to be a full database available.  This is due in part to many municipalities being involved in the addressing process, so thousands and thousands of entities.  For example, I am part of the team that creates new addresses for the City of Roseville, California.  The County we are in does the addressing for locations in the County outside Roseville.  So for the United States you can see how complex it can get as one considers each City and County has a hand in the process. (And each has its own addressing standards, which vary considerably, but that is another can of worms). Plus it is dynamic.  New addresses are being added and existing ones updated/corrected on a regular basis. What would you be using the addresses for?  Are you trying to find existing locations, like by Geocoding?  Depending on what your goal is, there may be a way to do it without having to create a database of all the addresses. Addressing  Chris Donohue, GISP ... View more

Here's background on what one can do with labeling: Building label expressions—Help | ArcGIS for Desktop  As for your specific request, in VB Script I believe one would employ a RIGHT function and in Python one would use SLICING. Right Function VB Script Cutting and slicing strings in Python - Python Central  Chris Donohue, GISP ... View more

To expand on Timothy Hales question, be aware that that at a scale of 1:1 or less, what is seen on the screen is not representative of the data due to the limitations of the software.  So while one can zoom way in (like to 1:0.2), what is visible at that scale is not an accurate representation of the data.  So at less than 1:1 good data will often appear to have gaps and overlaps; however, they are not real despite seeming like issues. Chris Donohue, GISP ... View more

I should also add that for many GIS people (myself included) the subject of projections and coordinate systems is not something that comes easily at first.  So if it seems mystifying, read up on it and then ask questions here on GeoNet.  There are many knowledgeable people here who can help.  And for the total puzzlers, here on GeoNet we are often blessed with the expertise of MKennedy-esristaff (ESRI coordinate systems expert). Chris Donohue, GISP ... View more

To build on what Micah Babinski stated, since Texas has multiple UTM zones, picking one UTM standard zone to try to use for the whole state won't work that well.  Instead, you want a projected coordinate system that covers the whole state.  That said, there are likely several available and it will not be obvious at first which one to choose.  Essentially all coordinate systems are a trade off between 4 factors:  shape, area, distance, and direction.  There is no coordinate system that preserves all 4; instead, each coordinate system is set up to preserve some of the factors at the expense of others.  So you will want to choose a coordinate system that matches the goals of your project. For example, if the goal is to have polygons with the correct area but are not so worried about their shape getting distorted somewhat, an Equal-Area coordinate system would be a good choice.  However, Equal-Area would not be a good choice if the goal is to show the true distance of lines. Choosing the Right Map Projection - Learning - Source: An OpenNews project  Chris Donohue, GISP ... View more

Any chance you still have access to ArcView 3.x?  If so, the option of doing it in Avenue would be available.  Might be worth a try if you have the script already and don't need to modernize. Chris Donohue, GISP ... View more

Another way to do this if you have many points and lines to process is the following: 1).  Make sure the point feature class has a field in the attribute table that differentiates the red and green dots, like Type or Class.  Also, make sure it has a Point ID field with unique ID's for each point. 2).  Make sure the line feature class has a Line ID field with populated with a unique value for each line. 3).  Create points at the start of each line.  Then create another point feature class to create the points at the end of each line: -  If one has an Advanced License, use Feature Vertices to Points (Data Management).  Point Type (optional) is Start or End ArcGIS Help (10.2, 10.2.1, and 10.2.2)  - If one has a lower license level, there is a workaround: How To: Create a start, midpoint, and/or endpoint feature class of a line with an ArcGIS for Desktop Basic or Standard l…  4).  Spatial Join the the original points to each of the point outputs from step 3. 5).  For the resulting point file with End points, add an EndPointID field.  Calculate the Point ID to this field. 6).  For the resulting point file with Start points, add an StartPointID field.  Calculate the Point ID to this field. 7).  Next, use an Attribute Join to add the Start Points to the Lines based on LineID. 8).  Do a second Attribute Join to add the End Points to the Lines in step 7. 9).  Export the resulting file to create a new feature class with the joined information permanently part of it. 10).  Remove all the extraneous fields (there will be several added by all the processing).  11).  The end result will be a line feature class that includes in its attribute table the start and end point classifications.  To find the ones that are disparate, do a Select By Attributes StartPointClass <> EndPointClass. Chris Donohue, GISP ... View more

An alternative method to find the longest flow length uses a Geometric Network after deriving the stream network from Spatial Analyst.  Refer to this pdf: Exercise 4.  Watershed and Stream Network Delineation GIS and Water Resources, Fall 2013 Prepared by David G Tarboton and David R. Maidment https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&ved=0ahUKEwjPoomymsfPAhVP2mMKHa3xD4oQFggsMAI&url=http%3A…  See page 57, and also the proceeding section on setting up the Geometric Network.  They do state that it is somewhat trial and error, though. Chris Donohue, GISP ... View more

Hmmm, I haven't done one of these in a few years, so I'm scratching my head trying to remember what I did to find the longest length once I had the stream segments.  I remember adding a Stream Order and a Stream Link to help organize the output, but forget what the process was to find the longest combination from the outputs. ArcGIS Help (10.2, 10.2.1, and 10.2.2) How Stream Order Works ArcGIS Help (10.2, 10.2.1, and 10.2.2) Stream Order ArcGIS Help (10.2, 10.2.1, and 10.2.2) Stream Link Chris Donohue, GISP ... View more

Typically, one would run the Flow Length tool on a hydrologically-correct elevation surface, then take the output raster and generate lines from it using Stream to Feature, then use the shape.length property of the lines to check the distance. ArcGIS Help (10.2, 10.2.1, and 10.2.2) - overview of the Hydrology toolset ArcGIS Help (10.2, 10.2.1, and 10.2.2)  - Flow Length ArcGIS Help (10.2, 10.2.1, and 10.2.2)  - Stream to Feature ArcGIS Help (10.2, 10.2.1, and 10.2.2)   - Flow Direction Notes: - These all require access to the Spatial Analyst Extension. -  Before one can run Flow Length and Stream to Feature, one needs to run Flow Direction.  It is assumed at this point that one has a "depressionless DEM" already; if not, there are several  processes that will need to be run first. ArcGIS Help (10.2, 10.2.1, and 10.2.2)  - Creating a Depressionless DEM Chris Donohue, GISP ... View more

Some questions to help clarify the issue: Can you label the two images you provided so viewers can discern what differentiates them? Does the issue involve any of the known points with the same pixel values also having the same X,Y values? Can you provide an image where the point values are labeled on the image by the point. Also, any chance there are data points to work with besides the very linear collection currently depicted?  I mention this as without more data points to the "sides" of the linear set you have, the interpolation out to the "sides" won't be meaningful.  I.e. interpolation doesn't provide anything useful in vast areas without data points. Chris Donohue, GISP ... View more

Visuals for the solution jborgion  offered: Chris Donohue, GISP ... View more

Not sure, but Select Layer By Attribute (Data Management) with the Selection type (optional) of Clear Selection may be what you are looking for.  However, this will not reset your Iterator, if that is instead what you are looking for. ArcGIS Help (10.2, 10.2.1, and 10.2.2)  Chris Donohue, GISP ... View more