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arcpy

One of the standards in our databases is to store dates as 8-digit integer values in the format of yyyymmdd. This requires us to occasionally convert values from date fields into this format. We can do this in the ArcMap Field Calculator using this arcpy function: def datetodouble(inNum): splitList = str(inNum).split("/") return splitList [2] +("0"+ splitList [0])[-2:] +("0"+ splitList [1])[-2:]
One of the common functions I have to do is assign each record in a feature class with a unique identifier–normally just a sequential number from 1 to N. In ArcView 3.x, the formula was simply ‘rec + 1’ if I wanted to start with the number 1. In ArcGIS, the process got a little more complex–you had to write a little VBA in Field Calculator as described by ESRI.
I have been working on a python script that I want (NEED) to run as a scheduled task on a remote machine. I got to the point that the script did exactly what I needed when I was interactively running it in a Windows session but had problems when running it as a scheduled task. The debugging process was cumbersome–make a change, schedule a task to run it, log out of the machine, and wait.
I’ve previously posted python code to check if a field index exists for both ArcGIs 9.3 and ArcGIS 10.0. Recently I have been working on a process that was using this code but it was not working because it looks for an index with a specific name. It was not working in this case because the name of the indexes was getting incremented as they were being created. For example, I was building an index on the table C5ST, field RelateId ([C5IX].
Random luck me to discovering a bug related to feature classes whose names start with ‘nd_'. It appears that you are allowed to create feature classes starting with ‘nd_’ but ArcCatalog will not display them. Further research shows this behavior also occurs for table and for ArcSDE (PostGres) geodatabases, personal geodatabase, and file geodatabases–I am using ArcCatalog 10.0. I first noticed something odd was occurring while importing a series of shapefiles into a geodatabases.
Discovered something today. I was working on an arcpy script that copies a raster dataset from a file geodatabase into a Postgres SDE geodatabase and then does some boring routine tasks–building stats, creating a mosaic dataset, adding the raster to the mosaic dataset and making a couple referenced mosaic datasets. It sometimes has trouble with the initial step of uploading the raster because of the sheer size of if (1m elevation raster for counties) and it failed today on one.
For some odd reason, I wanted to split all the arcs in a polyline feature class to a specific length–if a specific feature was longer than the target length, it would become two or more separate polyline records. Here is the bare-bones script that copies an existing feature class into a new feature class then processes each record, splitting it into multiple records if the polyline is longer than the user-specified tolerance.
During a process I was working on, I needed to compare a feature class before and after some edits. I did not quickly find anything in ArcToolbox but searching ArcResources led me to Change Detector script by Bruce Harold. After making a couple of tweaks–for some reason in one of my feature classes, the Shape field had an upper case ‘S’ and in the other it was a lower case ’s'.
I have to often get a table structure for a feature class or table into either a spreadsheet or word processing document. There might be an easy way to do this in ArcGIS 10 but I haven’t found it. So, as is my nature, I decided to roll my own. This is a bare-bones script that iterates through the fields, printing the field name, type, width, and precision. There are three optional features to it:
I was making an edit (adding leading ‘0’s) to a coded-value domain in an SDE database and realized that my edits were changing the order of the rows of my domain. Rows were moved to the bottom of the list when they were edited. So I went through the process of converting my domain back to a table, made my edits in Access and exported the rows to a .dbf in the order I wanted them.
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