Latest Contributions by DuncanHornby

‎10-24-2012

All, Have a look at this page on the ideas site, there is a comment about turning on an "always validate" on table. This works great if you are in TABLE VIEW mode. But who ever uses that when creating new features in a FeatureClass, especially now in ArcGIS 10 and the new template method? If you are going to attribute a feature you are going to do it in the Attributes Window accessed from the Editor toolbar. This does not enforce the domain range. So Gemma's idea still stands.

‎10-22-2012

Some of my analyses can generate many tables (not featureclasses) and storing them within a geodatabase is a logical and sensible approach. It has always frustrated me that I could not organize them better inside the geodatabase (personal/file). I would like to see a "folder" for tables inside the geodatabase and have no issue with the table names having to be unique.

‎10-17-2012

Peter, Having looked at the model (pretty impressive!) and the Help on AddJoin I was wondering if you should put a Make FeatureLayer\Table before the AddJoin tools? Just an idea? Duncan

‎10-16-2012

All, I was recently asked about edited an existing rectangular polygon in ArcGIS 10. Now I know when you create a rectangle you can use the rectangle tool and by pressing the keys L or W you can set the length or width. Once the rectangle is created there seems no way of getting back to those length\width dialogs. Is this correct or am I missing something? Duncan

‎10-08-2012

Szymon, If I have understood you correctly you have a polyline and want to find a point along it's length that is the closest point to a polygon and get the corresponding location on the polygon? The IProximityOperator Interface has a method called ReturnNearestPoint that will return the actual point on the geometry from a point. The IPolyline has a useful method QueryPointAndDistance, it may help? One problem I can think of when iterating through the point collection of a polyline is that the nearest location along the polyline to your polygon may not be a vertex but actually the edge of a segment within the polyline, totally depends on the shape of your polygon. Duncan

‎10-07-2012

Peter, A dataset with 7.5 million Features is pretty large! What ever you do it will take time to process. Loading dictionaries with 7.5 million entries will probably cripple a machine anyway... One quick win is to ensure your fields have attribute indices, have you created these? You can often get a significant performance boost with these alone. Duncan

‎10-07-2012

Hi, I am not particularly great with python so I'm guessing that %d thing in the whereclause of the cursor is some clever pyhton thing going on? My suggestion is to simplify that into something like: sql = r"FID > " + str(records_return) Then place the whereclause with sql string in the update cursor, its also makes it a lot easier to understand and debug! Also check that you are using the correct syntax for the field name, do you put in [] for example (e.g. [FID] > .....)? Just an idea... Duncan

‎10-04-2012

1988! Now you are just showing off! :)Your solution was what I was expecting but it blows my mind, definitely going away to have a good think about it.Many thanks!

‎10-04-2012

Abel, Whilst it's no book it's worth looking on the developer blog that esri runs. I found this page: http://blogs.esri.com/esri/arcgis/2010/05/05/add-ins-for-arcgis-desktop-10/ There used to be a really good book explaining ArcObjects using VBA, but that's been made pretty much redundant now as ESRI are removing all support for VBA. But ultimately you need to look at the help files and their samples and bash your head against a brick wall until it all works 😉 Duncan

‎10-04-2012

All, I managed to "dream up" a solution overnight! I wrap the polyline with a pointcollection interface and systematically remove a vertex and test if it still has a self intersection. Eventually it will remove a vertex that will stop it being self intersecting. I then go back to the original polyline and remove that specific vertex, et Voila! I don't know if this is a slick solution to the problem but it works. The only limitation I can think of is that this method expects the self intersection to be generated by only one erroneous vertex, which in my case is typically the problem. Duncan

‎10-03-2012

All, I have a river network and a tool I am creating is failing because there are self intersections in the polylines that make up the river network (see attached image of a good example of a polyline with this problem, these can be less than a meter in length so very hard to spot visually, unless zoomed right in). Now I've written some code that can go through the entire network and identify these "offending" polylines. I use the ITopologicalOperator and ask if it IsSimple, a False tells me that the polyline has a self-intersection. So I have a programmatic way of find these on mass but what I am unsure is how to fix these programmatically on mass. I need to remove these loops. As they are so small a simple deletion of a vertex will resolve this (don't care which one) and I have been doing that manually. I want to automate this but I can't figure out how to resolve it in ArcObjects. Has anyone tried to do this and willing to share their technique? Duncan

‎10-03-2012

Looking at your code you select out a county then use that single county to clip a layer called trex_clip? Looks fine to me. Although I would put an "r" infront of your text where you declare the workspace. So your line of code should look like this: gp.workspace = r"Y:\GIS_FILES\Georgia\GDOT\TSPLOST" Duncan

‎10-03-2012

Tai, I converted your code into VBA and it ran without error for me, is it something as silly as no write permisson to the folder? Duncan

‎10-03-2012

All, Very useful thread this, it saved me! I was getting the same COM error, found this thread, implemented Simplify and IsKnownSimple_2 but was still getting the error. I eventually solved it by adding a SimplifyNetwork of my polylines that I was attempting to do the Symmetrical difference on. So for the record my full code snippet is: pPolylineStart.SimplifyNetwork() pPolylineTest.SimplifyNetwork() pTopoOp = pPolylineTest pTopoOp.IsKnownSimple_2 =False pTopoOp.Simplify() pPolyline = pTopoOp.SymmetricalDifference(pPolylineStart) Thanks Duncan

‎10-01-2012

Philip, If you read the Help for this tool the very first thing it states under the usage section is this: All input rasters must be integer. A floating-point raster must first be converted to an integer raster before it can be used in Weighted Overlay. Duncan

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My Ideas

Latest Contributions by DuncanHornby

Re: Range Domain Validation

Re: Add ability to store feature classes and other geodatabase objects within a simple folder structure.

Re: ArcGIS10SP5: Add Join (ModelBuilder) still doesn't work?

Can you edit an existing rectangle (change length\width)?

Re: Nearest points on two geometries

Re: How to use Python dictionaries and update cursor instead of ArcGIS Joins?

Re: Trouble with using Update cursor to delete rows. - URGENT help required !

Re: How to remove self intersections in polylines using ArcObjects?

Re: ArcObjects Books for 10.0 (where?????)

I worked out a solution

How to remove self intersections in polylines using ArcObjects?

Re: Help with script I wrote that is only partially working

Re: Can't create Raster DataSet

ITopological Operator,HRESULT 0x80040218 on SymmetricalDifference

Re: Raster calculator output problem

Re: GeoPackage (GPKG) versus File Geodatabase (GDB...

Re: GeoPackage (GPKG) versus File Geodatabase (GDB...

Re: Dissolve polygons only within a given distance...

Re: How do I remove purple border around chart?

Re: How do I remove purple border around chart?

Coordinate Reference Systems

ArcGIS Arcade