Latest Contributions by RobertStevens

‎07-10-2021

I have to confess that I still do not understand this. I understand that if I ask for a buffer of radius one mile to be drawn that it may appear as an ellipse (although hardly detectable as such). I understand that if I have a map whose extents are large compared to the circumference of the earth that a circle of a given drawn at different latitudes/longitudes may appear to have a different size. I do not understand, when I ask to create a buffer which is a circle of radius one mile, that I get two circle of radii seeming different in radius by 30% or so. (still circles as far as the eye can judge) when the point around which I am drawing the circle has coordinates which are geographic instead of projected. The size of the circle should not depend on the coordinates of the point in question whether they be expressed as geographic ones, or projected ones. A point is still a point, and the displayed circles, whether distorted due to the projection or not, should appear identical. And they are anything but.

‎07-10-2021

Because the join is made in order to dissolve and/or ignore the joined features in a suitable way (sum, average etc) and ultimately to retain just one copy of the larger geometry. With disparate data sources there is a problem when boundaries of two polygonal sets do not quite match. Neither completely within nor intersect address this issue, whereas having the centroid of the smaller polygons with the larger does. Clear?

‎06-30-2021

Dan Thanks for reply and especially warning about Web Mercator. I am surprised, when I ran the tool, that there was no popup warning about coordinate systems. Of course, one should always read the description before using a tool. Fair enough. But I do not understand how, over a distance of one mile on the earth's surface, which is a small enough area as to be considered flat, that the tool I used based on a point with geographic coordinates can be off by 30%! There must be some bug in there somewhere.

‎06-26-2021

I have a point dataset: a single point whose coordinates are geographic (WGS_1984). The coordinates of the frame containing this layer are Web Mercator (Auxiliary Sphere). Using ArcGIS basic 10.8.1 I used the multiple ring buffer tool to create a single buffer of radius 1 mile. The tool runs and draws a circle. When I use the distance measuring widget to measure that radius it reports that the radius is 1.3 miles! I use the project tool to convert the coordinate of my single point layer to those of the frame (Web Mercator Auxiliary sphere). Use again the multiple ring buffer tool. This time the circle drawn is indeed much smaller, and the distance widget confirms that the radius is indeed 1 mile. OK. So you are going to tell me that I should not use that tool (and very possible other proximity tools) on a layer whose coordinate are geographic. Fine. But why does the tool not report this as an error? It know the coordinate systems of the frame and of the point layer. And how can the discrepancy be 30%? A one mile radius drawn on the tangent plane at a point on a sphere cannot possible differ from a one mile radius drawn on the sphere by as much as 30% - not when the radius of the earth is 4000 miles. It is only by shear luck that I realised I had a problem. Why is the software unable to alert me to this problem?

‎04-01-2021

About two years ago I first attempted to migrate to arcpro from arcmap. I had about 24 different maps and I put them all into one arcpro project. The consequence of this was that arcpro took forever to start, and sometimes crashed. According to ESRI, when pro starts it verifies, or attempts to access, or .. whatever.., every dataset in every map whether or not that map is the current one in Pro. Not good. I am once again going to try and migrate to Pro. So, my question is: what is considered best practice for a Project. How many maps is it reasonable to be contained in one project. Second question. All my maps use a common file geodatabase. Is it considered wise to move that geodatabase into the project, or is it best left where it now is. If I move it, I will have to change all the paths of all the layers in my maps that use data from my one file geodatabase. Thanks Rob Stevens

‎03-31-2021

Ty Tim. I am a bit hazy about using these web based APIs. But your posting gives me, I think, all I need to work my way through it, though have not tried yet.. I gather that for some of ESRI's tiled datasets there is one source which allows one to create an offline package, and another that is always up-to-date in real time .. or something like that

‎03-30-2021

I am using ESRI World Streetmap as a basemap. Can I dowload and store that tiling (as a .tpk ?) so that i do not need to be online when i run arcmap. I have roral internet and my maps take forever to load. I know these tilings can be cached locally but it doesnt seem to help with the drawing performace. Rob Stevens

‎04-10-2020

Running arcmap 10.7.1 windows 10 all latest patches etc etc. I am running this tool: Standard Toolbox => Conversion Tools => To geodatabase => Table to Table. My source is a feature class in a file geodatabase (.gdb). My output is a .csv file. This **** tool truncates my field names to 10 characters. Yes, if I were making a .dbf table that truncation would be necessary. There is no such restriction in the length of field names in a .csv, none whatever. So why does it do it? Because ESRI is not much concerned with the interoperability of their product with others. This is, once again, typical. This software is on its umpteenth release. This kind of imprecision, lack of attention to detail, lack of desire to dot the i's and cross the t's, lack of motivation to not saddle the user with the burden of working around these issues; this what characterizes ESRI's software. I swear that every day I use arcmap I run into some new irritation requiring me to interrupt my workflow while I have to code up yes another kluge.

‎02-28-2020

In May 2016 I filed an incident, 01765731 which was verified and confirmed as a bug, given id BUG_000096273. The gist of this bug is as follows: 1.geocode some addresses using World Geocoder online service 2. Umpteen fields are returned, and two of them are labelled X and Y and (at least with the options I chose for geocoding) are the longitude and latitude, presumably (although I would not trust anything ESRI does) in the datum of the geographic coordinate system used whether or not one requested a projected coordinate system 3. Some errors in addresses are corrected by hand. 4. Review and Rematch those addresses using the software and World Geocoder. 5. Now the fields X and Y for those corrections are no longer geographic coordinates but appear to be distances (Feet in my case, from some coordinate origin, but once again I have not the time or patience to go through all the calculations and verify) This BUG still has not been fixed. So I end up with a pile of data, some of which uses feet, and some decimal degrees. And here is the kicker which is why I bring this up again: 6. A second attempt to review/rematch an address fails. This very helpful message is displayed: "There was an error storing the modified result". Yeah, I'll say. I wonder if I could be forgiven for wondering why I should pay ESRI for using this service? There seems to be not the slightest volition to get these less-than-critical bugs fixed. Four years down the road and still not closed. BTW: this is not the only bug in the WGS. I have reported at least one other, and that too isn't foxed. It strains my belief to think that there can be many companies who are able to just continually ignore these bug reports and still enjoy any kind of customer base. Agree?

‎02-21-2020

I have numerous datasets using State Plane coordinates (North Oregon actually). I want to use the ESRI World Street Map,a tiling, as a basemap. It was created using World Mercator Auxiliary Sphere as cs. Am I correct in thinking that it will not work, unless the map frame itself also uses World Mercator Auxiliary Sphere? I don't believe tilings can be reprojected, and I don't believe that World Street Map is available in any projected coordinate system other than Web Mercator Auxiliary Sphere.True? In the past I used basemaps from Business Analyst. These were normal layers, available at several different scales, but which also admitted scaling to any arbitrary magnification, and could also be reprojected. I would prefer to keep using them. But if you try and import those feature classes into ArcPro (the future) you will crash and burn. Despite all the hoopla about ArcPro, it is just more of the same from ESRI: ever more sluggish, ever more bloated. (I know I can reproject all my existing datasets, or have them project on-the-fly. That is not what I am asking. I don't wish to be obliged to keep reprojecting, nor do I especially wish to use Web Mercator: there is a reason why local authorities use State Plane coordinates in their maps).

‎02-21-2020

I was able to get this to work, even though the arcpy documentation is not very good. It turns out that I really didn't need to expend the time and effort although it was a very useful learning exercise. I simply wanted a tool where I could rename several fields at once, the Alter Field tool in the standard ESRI toolbox only allows you to change one field at a time: having to run that tool a score of times is tedious. Instead you can use the Merge tool, but you only enter one file, and then change the names of the fields in the dialogue box. It has the disadvantage that you have to create a new feature class whereas Alter Field allows an in-place modification. I still do not properly understand this API. The dialogue box I get has a checkbox to set the field's visibility. But this is a function of a layer, not of a feature class (isn't it???). This whole arcpy toolkit really is second rate, and especially so the documentation that goes with.

‎02-16-2020

Hi David Amen to what you said in your second sentence. They are not well described in ESRI documentation, and my understanding, which can scarcely be the right word, is only superficial derived from reading the ad-hoc code of others. If I understand you properly, I think you are telling me that GetParameter() returns me an object of the type described in the the parameter list of the tool. I am coming up to speed with how to use these APIs (eg how to write meaningful stuff into the Results, and how to reports errors and warnings).

‎02-16-2020

Dan Onwards! I have an answer to my last difficulty. The problem was that with the data type of Field Info the Multivalue parameter property should be "No". I had it set to "Yes". I would say that the Multivalue property needs to be better explained in the documentation. Now I need to figure out how that data is returned to my python script. That is not at all self evident since there seems only the capability to read the data as a string. I am wondering whether it is some kind of JSON.

‎02-15-2020

Thank you Joe, thank you Dan. I used the procedures that you both recommended (actually, I am using Arcap, not pro, but it was easy given the toehold that you provided to find the corresponding pages in the latter). It was straightforward to get boxes for the input and output feature classes. I cannot seem to get the list of field renames to work. Nothing I do seems to allow me to enter values. In the list of types there is a "Field Info" type, and the GUI shows the boxes. But it does not allow me to enter anything. Even if I select a type of "String" with multiple values I cannot enter any data. I must have a severe misunderstanding of what these data boxes mean. I attach a screen shot of where I am right now.

‎02-14-2020

I have written a number of tools using arcpy as pure Python standalone scripts. Now I want to make an interactive tool that I can use, for example, in a model pipeline. I have the Python code which I can run as a standalone, and get the parameters from the python command line e.g python <script_name> <parameter1> ... <parameterN> All the tools supplied by ESRI have a GUI to interact with the user and collect these run time parameters. How do I do that instead of using the command line? Specifically I need to get the name of an input and output feature class, and also to collect a list of field name mappings (so there will be an a priori unknown number of these). I am not sure whether I am posting this question to the proper group. Please tell me if not.

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Date Last Visited	‎09-12-2024 03:19 AM

My Ideas

Latest Contributions by RobertStevens

Re: Multiple Ring Buffer and Geographic Coordinate systems

Re: Spatially joining polygons centroid within

Re: Multiple Ring Buffer and Geographic Coordinate systems

Multiple Ring Buffer and Geographic Coordinate systems

Best Practices for ArcPro Projects

Re: Download Tiling for Local Use

Download Tiling for Local Use

Table to Table Unnecessarily Truncates Names

Years go by and Bugs Remain Unfixed

Use ESRI World Streetmap as Basemap in State Plane Coordinates?

Re: How to Get User Input for New Python Tool

Re: How to Get User Input for New Python Tool

Re: How to Get User Input for New Python Tool

Re: How to Get User Input for New Python Tool

How to Get User Input for New Python Tool

Transform from NAD_1983_HARN to WGS_1984

Shape_Length and Shape_Area of Geographic Coordina...

Re: Conda. How can it be so slow?

Conda. How can it be so slow?

Activation of Conda Environments