Field calculators (available in QGIS, ArcGIS Desktop, etc) can recalculate the values of a single field on all, or selected, records within a table using an expression.

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Putting multiple lines of Python into ArcGIS 10's Field Calculator

I've gotten some incredibly valuable help here on this already, much Thanks. Entering these lines of Python one at a time works like a charm.... Just need one more seemingly simply issue solved... ...
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50 views

Python to create new fields in many layers / QGIS

I have a number of line layers on which I need to perform the same task: add 4 columns with the start and end points of each line. The expressions that I use to do this are: $xat(0) $xat(-1) $yat(0) ...
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51 views

Referencing other points(rows) in field calculator

I'm trying to calculate an angle between points using a field calculator. Is it possible to reference the previous or next FID with reference to the current one using the field calc? Eventually I'd ...
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1answer
53 views

Concatenate fields in Field Calculator using Python [duplicate]

I'm trying to concatenate fields together and used this post as a guide: <Adding hyphen in ArcGIS Field Calculator to merge two columns?> ; however, I'm still getting a 989 parsing error. Here's ...
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28 views

Field Calculator unexpectedly results in integer or decimal, depending on input

In model build, I have the following Field Calculator tool running: You can see in the results below that when the calculation involves a decimal, the output shows 6 decimal points, but when the ...
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68 views

How to use the field calculator in QGIS to determine the total of differents fields

I have an attribute table with 7 fields. I want my attribute " A1 " to be the total of " IP1 to IP5 ". I am not familiar with the request in the field calculator. How can I calculate the value of ...
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53 views

get day and time from date field with time, with field calculator

I'm using ArcGIS 10.1 and have a field containing a date and time I need to get the day of the week based on my date field and also when the same field that contains date and time I need to do this ...
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85 views

QGIS processing toolbox: fieldcalculator - update only selected features is not possible

I am working on a model where I need some calculations on only some selected features. In the normal fieldcalculator you can check 'only update ... selected features'. When using the fieldcalculator ...
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67 views

Python codeblock to remove numeric characters from a column not working

I am trying to make use of a codeblock found in this thread: How to remove numeric characters from alphanumeric value in field calculation? I put this code into the pre-logic script field of the ...
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222 views

Copy first row of attributes and paste for each feature

In a newly digitised polyline vector layer, there are 7 columns attributes value that are choosen inside a value map combo-box that MUST be exactly the same for every newly digitised line (I choose ...
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85 views

Replace Expression in Field Calculator to include a Numeric Range

There has to be an easier way to clean up address data, I hope? GeoCoding, I need to remove APT# and any number or letter that follows.
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Cannot convert string to int using ArcPy Calculate Field

When I load a csv file to join with ArcPy, it converts all string fields that are numeric to integers. Therefore, I have to add another field within the feature class that I'm using for joining that ...
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50 views

Unexpected behaviour when summarizing a field in ArcMap (Un-Equal strings)

I couldn't figure out why when I use summarize the Field " LandUse_Arabic " it the summary shows two identical values in the output table. But when I use select by attribute, despite the fact ...
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Converting values in datetime field to strings in text field using Python parser of ArcGIS for Desktop?

In the attribute table of my file geodatabase feature class I have a populated field called DateField of type date, and a text field called TextField. I have not yet hit on a way to convert the ...
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2answers
79 views

select parcels in polygons and add fiels depending on the polygons

I have a lot of feature classes (results of service area with different polygons (0 to 10/ 10 to 20/ 20 to 40 and 40 to 60) (figure 1) Also i have a shapefile with a lot of parcels (figure 2) ...
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160 views

Add a certain number of days for a date field

I have one field for a permit decision date, and then I have another field for 180 days from that permit date. The permit date field has data entered, but the 180 day field I would like to calculate ...
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152 views

Subtracting columns (that include null values) in ArcMap Field Calculator

I’m desperately trying to run a very simple command where I subtract one column with others. However the problem is that some rows have NULL values, therefore the result of subtracting is also NULL. I'...
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157 views

What is the expression for getting a subset of characters in QGIS Field Calculator?

I have a column of 10 character names e.g. L3NAM1988K. How can I delete the first 5 characters and the last 1 character using an expression in the QGis Field Calculator?
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129 views

Converting Aspect degree to westness

I have extracted Aspect values in degree from DEM in ArcMap 10.2 full license. I want to investigate effect of Westness in my model so I was using conversion formula of Folded Aspect : ABS (180- ABS(...
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1answer
77 views

Referencing fields in code block of Field Calculator in ArcGIS for Desktop?

I'm trying to use values from a field to fill a new field with a truncated version. The 'str.rindex' function is working out well, but I can't seem to figure out how I'm supposed to reference the ...
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2answers
111 views

Returning value from other field, using FieldCalculator

I am very new to Python and need what I believe is a very basic script in order for my field to represent another fields' input, if the field's value is 0. I tried to search for this, but gave up ...
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Field Calculator Python Expression Issues

I'm pretty new to Python and this is my first post on this forum so I could use some help. I am currently attempting to run some code in the Field Calculator in a model in order to replace string ...
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174 views

How to convert unix time to qt time type?

How can I convert unix timestamp to qt time type using qgis field calculator? I would like to avoid importing my table into excel and convert the timestamp to qt time type.
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How to compare string fields in the same table with ArcGIS 10

I don't know exactly if there is a tool for this or a maybe a python script could be more suitable. I want to compare string elements from a field (POI_NAME) with another string element in another ...
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229 views

Replace characters

How to remove a special number of characters of a string, e.g. the last 7 characters? And how to join them as the first characters to the string of another field? Thank you for VBS and Python synthax ...
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How to use DateDiff() Function across day transition in ArcGIS Field Calculator?

I am trying to calculate the time difference between two fields using the DateDiff() function in minutes. I have successfully calculated the times that fall within the same day but I am having trouble ...
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129 views

Decimal Degree data erases itself between edit sessions in QGIS

I have a shapefile with point data. I calculate the $x and $y of the points successfully I save the changes and close the edit session. Once I reopen the attribute table, the data after the decimal ...
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312 views

python add fields that may have NULL values

I would like to use python to calculate a field (short integer) using other fields (short integer) present in the table. In some cases these fields may have NULL values for one or more of the fields. ...
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240 views

Arcpy Calculate Field Formatting Syntax

I am trying to field calculate a double field (PID) to a new string field (PIN). Using: qry = '"139-{}".format(!PID!)' arcpy.CalculateField_management(out, "PIN", qry, "PYTHON") Given a PID = ...
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147 views

Populate an attribute table field using the 'startswith function

I am hoping that someone may be able to help me. I am new to ArcGIS, and even newer to Python. Working in ArcGIS 10.1, I have done is created a new text field in an attribute table, which I have ...
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1answer
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Calculating a field based on two other fields, if they exist [duplicate]

I'm using ModelBuilder to iterate through ~800 shapefiles to add and calculate a new field (I'll call it Field_A). Field_A needs to be populated by either Field_B or Field_C, whichever exists. Half of ...
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Python script for identifying duplicate records (follow up)

I am trying to calculate a field that marks duplicates and sequentially numbers them. I am using the code below that I found here: Generating sequential numbering for duplicate values in a field ...
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982 views

Generating sequential numbering for duplicate values in a field sorted by ObjectID

I am trying to figure out a solution to an field calculation problem. What I'm trying to do is automatically (using either ArcPy or the Field Calculator) generate sequential numbers, beginning at 1, ...
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438 views

Need a Python field calculation that works like the DatePart( ) VB Function

I have a field called Abandoned Year (short integer data type) that I am trying to populate with a four digit year from a column called Decommission Date (Date data type). I have done this in the ...
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1answer
146 views

using “abs()” function in QGIS field calculator?

I'm pretty new to GIS in general and I'm trying to take an absolute value of the difference between two fields in field calculator when creating a new field, but using ABS () returns an invalid ...
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1answer
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Incorrect field name resulted in RuntimeError: ERROR 999999 (Also, better code for adding and calculating fields)

This is the bottom half of my code (and it's been edited somewhat to share publicly). The code works perfectly fine when the fieldList has only three fields in it, but when I populate it with all 108 ...
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1answer
272 views

Syntax for ArcGIS ICalculator object?

I have a code snippet that I can't figure out: 'Define a calculator for NewArea field pCalculator = New Calculator With pCalculator .Cursor = pCursor .PreExpression = "Dim ...
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3answers
874 views

Field calculator script not working

I am trying to do the following in the field calculator in ArcGIS 10 if [IncdStDir] = " " then [IncdStNo] &" " & [IncdStName] &" " & [IncdStSfx] else [IncdStNo] &" " & [...
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Recoding values based on contents using ArcGIS Field Calculator or Python?

Is there a convenient (or even effective) method for recoding field values using the field calculator or standalone python script? In this case, I am given several unique strings to identify a type ...
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1answer
121 views

Calculating angle between polyline segments and assign this value to point?

I have a polyline feature with many segments (polyline split at vertices). I plan to record angle values to attribute table per each polyline segment and assign it to point features. I need to ...
2
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3answers
61 views

Stacking multiple selected points in ArcGIS

I would like to find a way to stack multiple selected points in ArcGIS, either using the field calculator or python script. For example, I want to snap all points representing houses on a street into ...
2
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1answer
47 views

Loading Features prompt in QGIS?

I'm currently working on a dataset with 3.8m records. I have a very simple expression to update a field that I want to execute using the Field Calculator, while having the Attribute Table open. Do I ...
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2answers
61 views

Sequential attribute field calculations with null values using Arcpy

I have a series of x,y co-ordinates converted from a .ply file. I was able to extract the file into a suitable x,y format for arcmap, the issue I have is that they are co-ordinate points representing ...
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80 views

Reproducing GRASS GIS network analysis tutorial in QGIS Field Calculator

Im looking to reproduce the assigning of road speeds as denoted in a GRASS GIS tutorial (v.net.alloc tutorial), where the road speed is assigned by road type (i.e. 'interstate' = 75 mph etc.) to then ...
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1answer
56 views

Calculate field using data from excel table

I need to interpolate data that I have in a excel file using data from an attribute table of a point feature. I want to create a new field on the attribute table with the result of that interpolation. ...
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1answer
128 views

Calculating percentage using QGIS Field Calculator?

I have a shapefile containing counties and their respective population for a given area. I woould like to use the Field Calculator to create a new field that contained the % of the total population in ...
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256 views

Controlling label/attributes of grid/fishnet index using ArcGIS for Desktop and ArcPy?

I have used the Grid index feature tool to create an index grid. The label/attribution of the page names are populated in a "row" orientated manner. eg lef to right a1,a2,a3,a4,a5,a6 b1,b2,b3,b4,b5,b6 ...
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How can I copy non-blank values to a new column from different columns in the same layer in QGIS?

My data: n1 n2 n3 NEW_COLUMN 11 null null null 33 null null null 55 My desired result: n1 n2 n3 NEW_COLUMN 11 null null 11 null 33 null 33 null null 55 ...
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32 views

Alphabetical Sort within a Record

I am performing a union on a polygon feature class with multiple overlapping polygons. Each of the records in the resulting feature class can be thought of as "unique area" polygons made up of the ...
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112 views

How to change GK-coordinates to UTM with the field calculator in QGIS?

i have a qgis project in ETRS89 (UTM) with some vectorshapes. i already transformes them from GK into UTM. but now the attribute table still show me the GK-coordinates. HOW can i change it? with the ...