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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How do I fill in serial letters (AA, AB,AC…,BA,BB,BC…ZZ) to a shape?

(I am using ArcGIS software, ArcMap...) MY PROBLEM I have a shape file containing points. The shape file contains 3 columns named FID, Shape* and Label. In the column I want to fill in AA, AB, ...
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179 views

How do I extract partial data from one field to another?

Answer Below I am attempting to extract a date stamp that is contained in one field and insert it into another field. The issue is that the date (in bold below) is not in the same location in each ...
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221 views

Field calculator script to work out first 5 dominant area fields?

I have 5 fields of different landcover types with areas of each and found below: > PRC_Water| PRC_Bare| PRC_Urban| PRC_LVeg| PRC_LVeg| > 5 20 40 20 15 I have ...
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Python Field Calculator ArcGIS 10 expression for a RANGE

what is the python expression for defining a range of numbers? I have tried numerous combinations but cannot get a simple range of angles (100 -200) to compute correctly. Screen shot : screen shot ...
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Using field calculator to delete specific contours

I have 3 contour shapefiles with 25m, 50m and 100m equidistance. Now I want to delete in the 25m-shp-file every **50m and **00m contour and in the 50m-shp-file every **00 contour. How can I show them ...
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How to replace arcpy.CalculateField_management with an update cursor?

I'd like to replace this expression arcpy.CalculateField_management(bufferFile, "Shape_Area", "float('!shape.area@squaremeters!')", "PYTHON") with an arcpy.da.updatecursor. The reason for this is ...
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608 views

Calculating the average / MEAN of an attribute field in a QGIS model

I need to know how to calculate the average / mean of an attribute field in my point shape file. Is this possible to do with the field calculator? I just found the options min or max but not mean. The ...
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286 views

Calculating Percentiles in ArcMap?

I have a large polygon dataset (26,000) records with numerous attributes columns. I wish to calculate the percentile rank of each attribute. Say I have population_density in an attribute, is there a ...
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134 views

Calculation based on features in shapefile

I hope I get the terminilogy right! Correct me if I mess something up. I need to perform some calculations for a scoring system for different habitat types. The Problem is that I have two different ...
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1answer
684 views

How to use %value% (from For iterator) in SQL expression of Calculate Field in ModelBuilder?

I have a shapefile with data of fish specimens and the coordinates where they were tagged for research purposes. One of the fields in the attribute table of these shapefiles is the fish length in ...
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439 views

Calculating order of points along a line

I have a shape file with transportation lines and another file with all bus stops along each line (with an attribute which links stops with specific lines to which they belong). I need to calculate ...
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Field Calculator decimal places - how can I limit them?

I've added a new column to an attribute table and performed an operation with the field calculator to populate the new column. The result is a column with a percentage. My problem isn't major but I ...
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100 views

Calculate difference between values in linear order using ArcGIS

The best way to describe this without knowing Python or VB jargon is to add these screenshots. I would like to emulate this Excel calculation in ArcMap10.1. MEAS is the distance along my route and ...
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How to set order of operations for Field Calculation in Network Analyst Evaluator Dialogue? [closed]

I desire to have a ratio calculated each time I create a new route. To get this ratio, I created and populated a field that multiplied the length of each segment by a designated number from 1-5, ...
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Calculating X and Y of line start and line end using ArcPy?

I have a series of polyline shapefiles and I am trying to automate the process of calculating the X and Y coordinates of the line start and line end using Python. I have added the 4 fields (startx, ...
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Simple field calculator equation in ArcGIS 10 not working

I'm new to ArcGIS 10 and am trying to do a really simple field calculator equation and it is not working. I'm just trying to find the percentage of a certain demographic trait by doing: ...
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How to replace null values in attribute table ArcGIS 10.2

I have a string field 'Oneway' with three values '+' '-' and Null showing a street accessibility, I would like to replace them with values 'F' 'T' and null as the script for Network dataset expect ...
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How to convert state name abbreviations to full names?

I have a data table with columns that includes city names (ex: San Jose) and state name abbreviations (ex: CA). Is there a way to define the state names as their full names (i.e., CA = California) and ...
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How do I add a hyphen to the Field Calculator to merge 2 columns?

I am trying to build a field calculator expression to merge two columns into one. I am looking for the word that makes it a range. Example: I have 2 columns in elevation, From and To. I want to ...
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ArcGIS 10/arcpy: Help needed with syntax for CalculateField_management in Python script

I need to use CalculateField_management in a Python script, and the calc expression needs to concatenate a runtime variable, a string, and a field (string) value. I have searched all over for ...
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2answers
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Way to find minimum value from a group of values - QGIS?

I'm wondering if there is a way to find the minimum value of a group within QGIS? Basically I need to find the minimum distance of each unique value in a table of about 5000 records. I can do the ...
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437 views

How to find/replace element in field with Field Calculator

I just want to perform the following operation done in Matlab into the Field Calculator using Python: p(p==0) = 0.001 ; p(p == 1) = 0.999; tVar = .5*log(p ./ (1 - p)) the operation consists of a ...
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How to count occurrences of one field grouped by values of another?

Is there a way of calculating the number of unique text strings in a field in ArcGIS 10.1? I have a number of repeated strings in this field, but would like to calculate the number of unique strings ...
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If/then VBScript/Python code equivalent to SQL IN ('x','y',z') expression in ArcGIS Field Calculator?

we need just like the following, only with multiple records selected... have tried the "xyz" in (1,2,3,4,5) SQL code but of course VB Script wants something else. dim f2 if [field1] = "foo" then f2 ...
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416 views

Cannot compute area of shapefile in field calculator of QGIS?

This shapefile represents the counties of NM. I am trying to compute the area of each polygon (yes, I know there is an area field, but this is a simpler example of a problem I'm having which doesn't ...
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How to insert a quotation mark through the Field Calculator of attribute table of a Shapefile?

I have a shapefile of polylines with information of diameter. But the problem is that i didn't enter the inch sign(") with the values of diameter. What would be the solution that qutation mark would ...
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Elseif Conditional Statement in QGIS Field Calculator

I am trying to write an ELSEIF conditional statement in QGIS Field Calculator (version 1.8.0). I have used an example I found online: CASE WHEN val < 0 THEN 'negative' WHEN val = 0 THEN ...
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using mod() with IF THEN field calculation

I am trying to use the field calculator to assign a "odd" or "even" value to a field of small integers. I usually do this with by selecting where: MOD([field],2) = 0 and then just calculating it ...
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Find and Replace expression needed in Field Calculator ArcGIS 10

Looking for the Field Calculator code (Python preferred) to replace the last numeral values in a field using another field's values for entire attribute table. Please see screen shot here:
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1answer
299 views

Converting 12-hour time to 24-hour time using Field Calculator

Does anyone know how to convert string time formats in ArcMap v10.2 from 12-hour to 24-hour using a simple query in the Field Calculator? i.e. NO Python, NO editing in Excel, NO changing my Windows PC ...
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318 views

Changing default parser in ArcGIS Field Calculator to Python?

Is there a way to change the default parser in the Field Calculator to Python? So annoying to always change now that I'm trying to move away from using VBScript... I'm using ArcGIS 10.1 for ...
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533 views

How to add attribute data up?

Sorry if this question is too simple/easy for you guys, but I'm still learning QGIS and pretty much teaching myself where I can. Is there a way to add data from 2 columns into one new column inside ...
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169 views

basic problem using division in field calculator

This is a very basic question, but I can't figure out what's going on. I've got election results I'd like to simply display as percentages rather than vote totals, which should be as simple as ...
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1answer
337 views

How to SUM field and then insert into NULL column?

I am only in the beginning stages of learning Python. I have a column, 'QUANTITY_SOLID', that I want to take the sum of all of its rows. I understand I can do this with 'SUMMARY_STATISTICS', but i'm ...
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190 views

Extract one GPS fix per day from data?

I am in the fortunate position of having 2 years worth of animal movement data. With such a large amount of data I would like to extract only one fix per day to make it easier to work with. Data = 14 ...
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How to Calculate Field in joined table using ArcPy?

I have to calculate a field based on another field in a joined table, but an error occurs: "Parameters are not valid. ERROR 000728: Field !Table_A.field_A! does not exist within table" My code: ...
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Field Calculator VB Script Codeblock IF statement syntax is wrong?

I can't figure out why the syntax is wrong in Field Calculator ArcMap 10. The complete codeblock is Dim CapitalDia As Number Dim TwagDia As Number Dim X As Number CapitalDia = [New_Pipe_S] TwagDia ...
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split string after first word

I want to split a string field after the first word using the space as a delimiter so that "WA ROSSOUW ORANJE BELEGGINGS" becomes "ROSSOUW ORANJE BELEGGINGS". I am using Arcmap10. Thanks.
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Moving “last name” from last to first in the Attribute Table

How do you get e.g. "John D. Doe" to "Doe, John D." in the AT using VB Scripting without going individually going through each line? I am using ArcGIS 9.3. I should note that not all the names are ...
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Is there a Log or Ln function in QGIS Field Calculator?

I can't seem to find any way to take the logarithm (natural or base 10) of a field in QGIS. I have gotten to the field calculator but there is not a button for log and I can't seem find any formula ...
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Field calculation- Arcpy

I am developing a script to calculate the values of two fields (C and D) based on value of field A (It is a Point feature): A C D 0.2 1 1 0.2 1 2 0.2 1 3 0.4 2 1 0.5 3 1 0.5 3 2 So the idea is n ...
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Iterative position within Field Calculator/Python

I'm not great with Python or programming in general, so I'm not even sure how to ask this question. Basically what I've got is in the left column, and what I want is in the right column. UniqueID ...
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Nested “if” statements in ArcGIS Field Calculator

The solution in VB for the base process is @ "If then" VB Script code (or Python) equivalent to SQL's IN ('x','y',z') expression in ArcGIS Field Calculator question? ...
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1answer
455 views

Calculate Field in ModelBuilder gives General error executing calculator. ERROR 999999: Error executing function. Expected end of statement?

I am attempting to do zonal statistics for multiple images and I need to add an extra field that will have the name of each raster file in each row to the finally appended file. I have added a field ...
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Can Hyperlink be based on two fields for path and file name separately?

I need to create a hyperlink field. I have one field with the file name, and another field that contains only part of the file path (the real path is unknown). The table contains 14,000 records with ...
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How to do a simple find and replace in QGIS field calculator?

I'm trying to replace selected string values in an attribute table, eg. "Text1" for "Text2" (QGIS 1.8.0), patriculary for those rows with NULL values. I have been trying to use the replace expression ...
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891 views

Why can't I multiply two string fields in the Field Calculator by converting them to int() and float()

I'm using ArcGIS 10 and new at python scripting. I have a string field that I need to calculate by multiplying two other string fields. I can do it in python using two arbitrary values... CINPT1 = ...
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VBA functions use in ArcGIS Field Calculator

Would this be ok to use them for the field calculator in ArcGIS 9.3 ? See here MS Excel VBA Functions Or should I fix them in MS Excel and save as a file and then use the join with the shapefile or ...
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Replacing multiples words using field calculator in attribute table python

I need to replace multiple words with one word in a field at one time in one script. Example in my LettersField I need to replace all the "Aa" and all the "Bb" and all the "Cc" with "Rr". I am ...
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264 views

How to use Field Calculator to assign values to only Odd (or Even) page fields for Data Driven Pages?

I am creating a map book but do not want the page numbers for each map page to be on the same side (since its printed double sided), I need the page numbers to be placed on opposite sides? I am using ...