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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Field Calculator - How to evaluate and sum multiple fields?

I'll do my best to describe the problem - my main issue isn't so much the python code but rather the logic I'm using. The file I'm working on is a polygon shapefile with forest attribute data. In the ...
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1answer
188 views

Calculate Field based on two fields using python

I'm trying to calculate new values for a field based on two other fields. In VB I don't have any problem, but I need to use python to publish my gp service.
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1answer
556 views

How to create a Qgis python script to manipulate fields with some parameters?

I'm just beginning with QGIS. I have a shape file with 10 fields field1, ..., field10, and many thousands of data. I will like to automatize the next sequence (in a python script or a model): load ...
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1answer
55 views

Categorizing GPS data based on cumulative time using ArcGIS Desktop?

I have GPS data which includes “Lon”, “Lat”, and cumulative Time from 0 (sec) as fields. I want to add an integer variable new field, “Trip,” which starts from zero, and is incremented by one after ...
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111 views

How to add column to attribute table using field calculator with $length function?

I used the following code to add a separate column to the attribute table with the length of features. from PyQt4.QtCore import QVariant from qgis.core import QgsField, QgsExpression, QgsFeature ...
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266 views

Remove Leading Zeros with QGIS Field Calculator

I'd like to take this attribute value: "MAP_PAR_ID": "0160011000", and populate a new field with "16-11". This works: concat(substr("MAP_PAR_ID",0,3), '-', substr("MAP_PAR_ID",5,3)) but i need to ...
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74 views

Using Field Calculator to fill out a list of unit numbers

I am adding address points for individual units in trailer/RV parks and I would like to be able to use the Field Calculator to assign the unit numbers. Is it possible to tell the Field Calculator a ...
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1answer
109 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
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63 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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Field Calculator QGIS: CASE WHEN [duplicate]

at first, sorry for my English. I'm using Google translator. I have a .shp file with attribute table. Like this... -- A -- -- B -- -- C -- QString Double Double Data ...
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88 views

Averaging XY data for locations in QGIS

I wanted to find out mean of the selected point using QGIS. I tried out selecting using attribute table but could not find an option for mean in field calculator. I have attached a screenshot with ...
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195 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: ...
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102 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 ...
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2answers
517 views

Writing Python script in Field Calculator in ArcGIS Desktop?

I'm a programmer, I have programmed in C#, Java, but not with Python. And I'm not a geographic worker. How can I write a python script into Field Calculator to be able to check the other column value. ...
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1answer
94 views

Concatenate fields value excluding empty values

I need to concatenate the value of two fields excluding empty values, using Field calculator. The fields are: AREA_HI and AREA_LO I have tried using a Python script but ArcGIS returns an error ...
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1answer
58 views

Is there a way to automate field calculations for ArcGIS Server?

I have a field that I'd like to be concatenated with each new objectID when a feature is created in my feature service. Workflow: Feature added, already contains objectID. Would like my Service ...
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1answer
635 views

Slow performance with Add Join and Calculate Field?

I have a point layer and a table with approximately 100 fields. I need to join the table to the point layer based on a key field and create a new shapefile / feature class. This script has been ...
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1answer
814 views

ArcGIS 10.0, Field Calculator Nested “if” statement with strings

I need to assign a value depending on other two columns "FNP" and "Teilort". I wrote this script in phyton for field calculator. It actually works (no error messages) but the results in every cell is ...
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101 views

Geometric functions in field calculator in QGIS

I had a look in the manual of QGIS and I also browsed the Internet to find some useful information about the geometric functions of the field calculator. I've found this post but I'm still confused. ...
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1answer
362 views

Finding distance between consecutive points using ArcGIS Desktop?

I am wondering how I can get the distance between consecutive GPS locations in ArcMap 10 (i.e. the distance between consecutive GPS locations sent in during a wildlife telemetry study).
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2answers
554 views

How to delete last part of a string starting from the 1st non numeric character? [closed]

I'm looking for a Python or VB statement to remove the last part of a string, starting where the 1st non Numeric character appears, using the Field Calculator in ArcMap 10. Here's an example of what ...
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308 views

Iterate calculate field in multiple tables in ModelBuilder

I would like to iterate calculate field in multiple tables using ArcGIS Model Builder. The figure below explains details of the calculations. My existing model calculates value only for the first ...
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113 views

How to handle “Error: Town not found” when updating an existing field with Field Calculator?

I want to update a field in field calculator. update existing field is checked. Column to be updated : Column2 CASE WHEN "COLUMN1" IS NOT NULL THEN "COLUMN2" = "Town" ELSE ...
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275 views

How to flip, or invert attribute tables with respect to row ID arcgis

I need to invert the fields of an attribute table relative to the row ID field. As a very simple example of what I need; if the row IDs of 1, 2, and 3 corresponded to identical values in another ...
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2answers
2k views

How to replace “NULL” value with Zero in geodatabase table

I am having some difficulties to change "NULL" values to zero in geodatabase. I have tried the following python code in ArcGIS 10.1 ("Field Calculator") to change it but did not work. Pre-Logic ...
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2answers
95 views

ArcGIS Field Calculator passes European-formatted floats as tuples

I have the problem that the ArcGIS Field Calculator doesn't read a float number when it is included in Python by referring to the field that contains it, in this way: def giveResult(floatValue): if ...
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326 views

How to calculate cumulative decreasing sum in ArcGIS-10.2

I need to calculate the cumulative decreasing sum as a field in a rasters attribute table. The cumulative decreasing sum is the accumulation of the last values to the first, so it is basically the ...
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2answers
105 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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940 views

How to Calculate Cumulative Field Values in Arcmap

My problem is conceptually quite simple; In Arcmap 10.2, I wish to create a field which contains the cumulative values of another field in the same attribute table. For example, if the first three ...
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1answer
148 views

How to calculate square footage from multiple records into one field?

I want to add up the square footage for each building floor and enter the total into another field within the same feature class. Each floor has a different size and is a separate polygon with a ...
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2answers
587 views

Calculate Fields with Null Values using arcpy.da.UpdateCursor of ArcGIS for Desktop?

How do you calculate fields with null values? I have multiple fields that may have null values, that aren't being calculated in the third field. import arcpy with ...
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1answer
166 views

Trouble calculating areas in QGIS using field calculator

I am testing various projections to calculate areas using ICES statistical shapefiles and the QGIS field calculator. I am using ICES areas downloadable from the following link: ...
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192 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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341 views

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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1answer
380 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") ...
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155 views

Why will my field calculator python function always return Null if any inputs are Null?

I've written a simple python function that outputs a list based on yes/no fields. It appends a word to a list if it has a "yes" in another column then writes the list, formatted according to the ...
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373 views

Cumulative field calculation using Python in ArcGIS for Desktop?

I am using the following Python code to sum cumulatively but I need the summation to take place while the other field is equal to 1 and then again start the summation when it's equal to 2. I need the ...
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2answers
186 views

How to calculate area of shapefile with a merged layer

so i have 'save as''d the new project and layer with my new Custom CRS project string being '+proj=laea +lat_0=70 +lon_0=0 +x_0=0 +y_0=0 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs'. ...
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172 views

How I can reverse numbers in a string without reversing any text? [closed]

I have a string, I need to reverse just the numbers in the string without the text: String: [321 test] The result will be: [123 test]
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1answer
2k views

Meaning of exclamation mark in Python parser of ArcGIS Field Calculator?

In the following line, I don't understand what those exclamation marks mean? And why put everything in quotation? I don't understand the purpose of the variable expression, please explain to me as I'm ...
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1answer
673 views

How to calculate unique IDs starting from highest current ID

I have been using a python script in field calculator in ArcGIS 10.2 to add unique IDs automatically, however there are two things I would like to improve this process: Each ID also has letters at ...
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2answers
470 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 ...
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3answers
136 views

If/then Field Calculator

I have two fields in my model, the first is a spatial join return for the township, the second is a spatical join to a city. If there is not city, then the field is left blank. The column that has ...
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141 views

Concatenate an object ID and string to publish gp service with field calculator?

I have a simple model which concatenates and object id and a string, to create something like 1SRS2567, the concatenate function of OID and the string field are able to be passed in VB, but not ...
3
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1answer
223 views

How to calculate the intersected area from a layer with overlapping buffers in qgis

I need to calculate the area of landusetypes in 50m around various dots (all in one shapfile). My problem is, the buffers around the dots are overlapping each over in some places. I tried to ...
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70 views

Syntax to add attributes in a line in the Expression String Builder

I have several columns with certain values, here's an example: | Apple | Banana| Orange | Pear | Expected result | 1 | 1 | 1 | 1 | red | 1 | 2 | 2 | 1 ...
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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 ...
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425 views

Why is this field calculator expression evaluated incorrectly when using Python syntax?

I have a polygon featureclass containing an integer field 'gridcode'. I've added 2 new float fields VB_calc and Python_calc, both of which should be equal to gridcode / 1,000,000. If I calculate the ...
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1answer
675 views

Concatenate multiple string / text fields some of which may have NULL values ArcGIS

I am trying to repeat the behavior of this code from the ESRI website. I want to replicate the output example in ALL_Type field, so that it concatenates a field but it deals (ignores) any that have ...
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128 views

Calculating Field B from Field A, except where Field B has existing value, using ArcGIS Desktop 9.3?

Im trying to calculate Field B from Field A except where Field B has existing value in ArcGIS Desktop 9.3. (I suspect its straight forward but I have 'searched' and havent cracked it yet) Any ...