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.

learn more… | top users | synonyms (1)

1
vote
3answers
60 views

Generate a string based on an integer range

After some initial research, I was unable to find a solution for the following issue. I'm sure there's an answer to this question already floating around here somewhere, but hopefully someone can give ...
1
vote
4answers
170 views

How to remove period, comma, symbols using field calculator?

I want to delete . , # in attribute table using field calculator (VB Script or Python). How can I remove these using this example address: N. First St., Unit #1 (I don't need city or state name) I ...
1
vote
2answers
143 views

Calculate field management not working within customized Python tool in ArcGIS

I am trying to make a custom made Python Script tool which I would like to use in Model builder. I am using the arcpy.Calulate_field_management function (simple reclass function as an example), but it ...
1
vote
3answers
465 views

Extract numbers from string field

I am trying to calculate field test2 with only the numeric values from a string field test. The entire script is like: def makestr(test) list=[] for s in test: if s.isdigit(): ...
1
vote
2answers
119 views

Using Python For a Field Calc

In AcrMap 10.2 I'm trying to add a field and run this script in Field Calc: !shape.isMultipart! to see if I have any multipart lines. I keep getting geoprocessing failures. I am clicking the ...
1
vote
3answers
2k views

How to Convert a Number to Percentage in Field Calculator

Using ArcGIS 10.2 and Personal geodatabase,I have a field with values of Numbers like 0.461538 and Type of "Double" can you please let me know how I can Export them to new Field in Percentage Format ...
1
vote
3answers
222 views

Conditional Statement for attribute data

I'm trying to write a conditional statement that references another field within the same shapefile layer. I want it to only do so if the one field is " Null " and leave is alone if there is already a ...
1
vote
2answers
252 views

How to get a string from a Double with a fixed number of decimals?

I have a featureclass (in a File Geodatabase), with a particular field of type Double. I want to copy it over to a text field, so that only 3 decimal places are shown. For example: 34.78902345 ...
1
vote
2answers
1k views

Debugging ERROR 000539 from CalculateField in ArcPy?

I previously successfully used the sample code here: How to calculate Field using part of filename in ModelBuilder? # Import standard library modules import arcpy, os, sys from arcpy import env # ...
1
vote
2answers
195 views

How to select only areas bigger than x acres?

I would like to create a new shapefile from another area shapefile. The new shapefile should only contain all areas that are bigger than 5 acres (10.000 m²). How do I do this?
1
vote
3answers
558 views

Replacing Variable in VB-Expression-File (.cal) of ArcGIS Desktop?

I'm trying to modify a VB-Expression saved in a cal-file by ArcGIS Desktop 9.3: dim out if [D19830701]=-9999 then out= [D19830501] else out= [D19830701] end if ...
1
vote
2answers
75 views

How to generate random points from FIDs using ArcPy or ArcGIS Field Calculator?

I'm trying to generate a shapefile of random points using FID from the attribute table. My attribute table has 800,000 features and I only need a sample of 240. Is there a way to do it in arcpy or in ...
1
vote
2answers
108 views

How do I add rows together to populate a new field?

How do I add the values in columns 11_acciden, 12_acciden, 13_acciden, and 14_acciden in order to populate the total_acci column?
1
vote
1answer
203 views

python expression convert field to string and format with leading zeroes

I would like to create an expression using the field calculator in ArcMap to be able to convert an Int field to a string and add leading zeroes. I am able to do it in a python window with an example ...
1
vote
2answers
131 views

Calculate Fields from 3 different fields using ArcGIS for Desktop?

I'm using a shapefile of different vegetation and land cover types and I want to generalize to a simpler classification (ie. I only need to differenciate between young and old forest and open land, ...
1
vote
1answer
93 views

Extracting data from Address field using ArcGIS for Desktop?

I am fairly new to using python in field calculator and could use some help. I want to populate SitusRdType with RD or AVE or LN or ST or DR depending on the road type. I also want to just have the ...
1
vote
2answers
169 views

Field Calcuator to add percent using Python

What might I go wrong here is that I am trying to add percent. I use the Field Calcualtor and it keeps getting an error. I am opening the Table to add a field named Percent and then type this: ...
1
vote
1answer
295 views

Simple field calculator equation in ArcGIS 10.2.1 not working with python parser

I am trying to calculate a percentage in a field in a table. customers and total_customers are short integer fields. arcpy.AddField_management(tableSepSel2, "percent", "DOUBLE") ...
1
vote
2answers
863 views

Concatenating text and string in Field Calculator expression (python)

I'm trying to copy an attribute value from one field to another (sum of raster values), but I'm having issues in writing a functioning expression for a Calculate Field script. I'm adding a field ...
1
vote
1answer
3k views

How to search text string and select item in QGIS?

I have a table attribute with complete roads name. I have to search items by digiting a part of the road name and I need to colour all the items selected. eg: ROAD NAME: / road 01 / road 02 / road 11 ...
1
vote
1answer
755 views

Using Python if/then/else to return value from either of two fields based on value of third using ArcGIS Field Calculator?

I'm trying to avoid manually inputting Begin and End engineering station values already inputted into a seperate field. I'm dealing with(4) fields: Begin_Sta End_Sta Beg_End and Station. The ...
1
vote
3answers
895 views

Automatically assign numbers to point file in various order in QGIS

I know how to automatically assign numbers to a new point files using the $rownum function in the field calculator. However it does it from the top-left over and down like reading a book. I could ...
1
vote
1answer
30 views

Debugging Indentation error on Python Parser of ArcGIS Field Calculator?

Would anyone please help me find out why I get an indentation error in line 3 def calc(f1,f2,f3): remove_list = ['01ST', '02ND', '03RD', '04TH', '05TH', '06TH', '07TH', '08TH', '09TH'] if f2 in ...
1
vote
2answers
42 views

QGIS upper round in field calculator

I need to to in the field calculator the following calc: toint(Field1 / 25.0) but i need to round the result to no decimal places but upwards. Exmaples: If 17/25 result should 1. If 25/25 result ...
1
vote
4answers
217 views

Calculate Field with Python Issues (If statements)

I don't know a whole lot about python and scripting, so I was hoping somebody could give me a couple pointers on fixing some code. I am trying to calculate a "final results" attribute field. The ...
1
vote
1answer
95 views

count how many times an attribute is repeated, using “field calculator”

I'm using Arcgis 10.2.2 there is a way to count how many times an attribute is repeated, using the "field calculator" to make a selection after example of repeating more than 20 times
1
vote
1answer
92 views

How to work with accentuated strings in Python scripts in ArcGIS Desktop Field Calculator?

` pre-logic: def myCalc(name,nameVal): if (name == nameVal): return 1 else: return 0 var_name= myCalc(!Epulettipus!,"Lakóépület") ` This doesn't work with accentuated strings. (But ...
1
vote
2answers
337 views

How to concatenate double with string in field calculator with Python expression?

I'd like to concatenate my lat/lng with a few string fields in ArcGIS. What is the correct expression to use, avoiding VBA. I don't want to convert the lat/lng fields to string either. my 4 fields ...
1
vote
1answer
78 views

Calculation of a text value, The value of which is separated by a special character

How can I calculate a text value, the value of which is separated by a special character? For example: dog | duck, I would like to keep the first value: dog or elephant | cat, I want to keep ...
1
vote
5answers
204 views

Calculations in if statement

I want to perform a simple calculation with the Field Calculator using this piece of script (note that all the elif statements are attempts for another syntax and non of the worked): def ...
1
vote
1answer
699 views

How to sum up multiple columns values into one single column

I have one table containing many columns. Using field calculator, I want to create a new column containing (for each line) the sum of all columns values. Pretty dumb, but just cannot find the correct ...
1
vote
2answers
264 views

Creating a new integer field based on text in a different field - ArcGIS 10.1

I need to create a new integer field based on another text field. All instances of a the same text string in the existing field should be assigned the same number (starting at number 1). Can I do this ...
1
vote
1answer
130 views

How to write a expression in field calculator for finding $X and $Y?

I'm trying to calculate the lat/long of points using the Q GIS field calculator.Nathan W suggested to First, save the layer as WGS84 and import it again. Then in the field calculator you can use $x or ...
1
vote
2answers
399 views

How to write a QGIS regex for rounding to two places after the decimal point?

In QGIS field-calculator round() is not working in QGIS 1.8 so I try to do the following with a regex: I'd like to keep the first two places after the decimal point - where do I go wrong? ...
1
vote
2answers
580 views

ArcPy Field Calculation with special characters

I'm trying to calculate a string field, using "µSv/h". Running this in the manual field calculator works just fine, but I've tried this in the Python window in ArcMap as well as the IDLE, but both ...
1
vote
1answer
86 views

How to fill inn A, B, C …Y, Z, A, B, …Y, Z, A, B, and so on? [duplicate]

as a second part of a problem i am trying to solve. I need help to figure out how to fill in serial letters.. Starting at A.. going to Z and starting over at A again.. I have a tabel with numbers ...
1
vote
1answer
169 views

Calculating values of field based on two others using Field Calculator in ArcGIS Desktop?

I need to combine two fields in an attribute table. I want to do this using the field calculator. What is the proper script to write to combine a field called "name" and "type", so that it produces ...
1
vote
1answer
23 views

Calculating field on insert (real time) using QGIS?

We use QGIS as a field application. We like to calculate with a input value and then also calculate with the result of the calculation Example: Liters: 1000 -> Liter per container: "this has to be ...
1
vote
2answers
58 views

using field calculator on string field that has some empty values?

I have a CityState field that has the city and states of landowners. Bellingham WA, for example. I am making two new fields, OwnerCity and OwnerState in which I strip the last two characters of ...
1
vote
1answer
48 views

How to calculate azimuth in QGIS field calculator?

Is there any way to calculate the azimuth of two points in the QGIS field calculator? The coordinates are stored in an attribute table. x1 | y1 | x2 | y2
1
vote
1answer
35 views

How do I move the last two characters of a column within the attribute table to another column?

I have data in a column that looks like the below example: El Monte CA I need to move the last 2 characters to a separate column. Which function in the field calculator will deliver those results?
1
vote
1answer
60 views

Conditional Statements in Arc Map 10 (field Calculator)

I'm attempting to calculate the values of a field based on IF THEN statements in ArcMap 10 (in field calculator) but I haven't succeeded yet on that. What I want to add is the following expression: ...
1
vote
1answer
60 views

CalculateField with variables

I'm trying to make a python script on arcmap 10.2.2 which will copy values from an old field (selected by the user) and paste them in an new field (named by the user). I wrote that: fc = ...
1
vote
1answer
82 views

Create new attribute ranking polygons by size in QGIS

I'd like to create a new field in the attribute table which gives the rank of the polygon by size. For example, the polygon of the largest size would be rank 1 and the smallest rank N. I was hoping ...
1
vote
1answer
70 views

Add and Calculate Field in Table with ArcPy?

I have written the following script to iterate it as a tool for all my tables with ModelBuilder, but i have a problem wth my codeblock. I want to add a field FID to all my tables and to add the values ...
1
vote
2answers
61 views

How to update a bulk selection of fields using field calculator in QGIS 2.8.1

I have an attribute table showing vegetation communities. The table has three columns ("ID", "Veg Comm" and "Area_ha". Instead of having to copy and paste text after each polygon created into each ...
1
vote
2answers
54 views

How to remove a certain number of digits from the front or end of an attribute field?

Can I use the filed calculator in QGIS somehow to remove the first 4 numbers in all attribute fields in a column? Example 16011234 -> 1234 EDIT: Silly, I can just subtract with 16000000 in this ...
1
vote
1answer
56 views

If statement problem in Field Calculator - Arcgis

I have a field entitled "Lung_lunc". It contains some "0" values and the rest are values > 0. I want to turn those "0" values, into "0.0001". I have added a new field: "Lung_lunca", and I want to use ...
1
vote
1answer
69 views

ArcGIS Field Calculator nested elif is None not working

I am calculating a field based on two other fields in ArcMap 10.2 using python. My Pre-Logic Script Code is def myfunc(legend,Btype): if(legend == 'Apple'): return 'Banana' elif(legend == ...
1
vote
1answer
98 views

How can I allocate a $rownum in reverse order in QGIS?

How can I allocate the $rownum value in reverse order in QGIS? I have a created a grid layer to use in an atlas and the ID allocated is from top left to bottom right - which is what I want if I want ...