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 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 ...
6
votes
1answer
690 views

How to add attributes in proportion to intersecting area from another layer

I am new to using QGIS. I have two polygon layers: Voronoi of Access Points Census block maps with population I want to get number of people covered by each Access Point (Assuming uniform ...
6
votes
1answer
246 views

Calculating a Unique ID on a Subgroup of Polygons

I would like to assign a unique ID to polygons in a dataset. The catch to my issue is that I would like polygons that fall within a polygon to have the same unique ID. My example is related to ...
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0answers
52 views

How to undo field calculation in ArcGIS Pro

I am using ArcGIS Pro and cannot find a way to undo field calculations. With ArcGIS, field calculations could be undone when an edit session was active, but Pro seems to be in a perpetual edit ...
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3answers
13k views

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: [asian]/[...
5
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2answers
2k views

Arc 10 field calculator scripts

I need scripts for the field calculator that: extracts the first word from a column, i.e. "Jones School" - "Jones", and A script that will capitalize this new field, "Jones" - "JONES". This is Arc ...
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5answers
817 views

How to combine text and integers in a string field?

I have field with numbers in it (field type: double, number format: numeric) and I need to create a new field and put text in front of the numbers. I know that I need to add a new string field, but ...
5
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1answer
5k views

Python If else statements

I'm trying to populate a field from another. The catch is that it isn't 1 or 2 values. If my field A = 4 then I want it to return field B to 0. But if Field A is 1, 2 or 3 then I want the user to be ...
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1answer
3k views

Converting state name abbreviations to full names using ArcGIS Field Calculator?

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 ...
5
votes
1answer
5k views

Using VBA in ArcMap field calculator?

I am trying to use ArcMap's Field Calculator to populate values in a column based on a value in another column. So, in pseudo-code: if [field1] = 'Foo' set [field2] = 'Bar' endif Something like ...
5
votes
2answers
562 views

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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5answers
4k views

ExecutING SQL script in ArcGIS field calculator?

I am trying to transfer over row data from a table to columns in a shapefile table. There is a common "SA" variable between the two (i.e. the study area number) but there is more than one land use ...
5
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1answer
527 views

Translate Excel formula to be used in field calculator

I have a series of equations to create corner points to make rotated polygons based on angles in the attribute table, but I have created it in excel and can't figure out the syntax to get it to work ...
5
votes
2answers
982 views

Capitalizing The First Letter Of Each Word In Attribute Field

Does anyone know of a way to capitalize the first letter of each word in a field in an attribute table? I am doing this in QGIS. I know of field calculations to change all the words to Lower or ...
5
votes
2answers
356 views

Calculating Quarter (Q1, Q2, etc) using Date field in ArcMap Field Calculator?

I am using ArcMap 10.0 and making a map where I symbolize on annual quarter (i.e. Q1 2013, Q2 2013, and so on by quarter through 2015). If a date field contains this: 01/15/2013, and I wanted to ...
5
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2answers
2k views

How to add a sequence to the attribute table?

Is there a way to use the field calculator in QGIS to create a range of values in a count sequence with a specified input range? For example, if I wanted to have the values 1 to 5 repeated within my ...
5
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2answers
458 views

Filling in patterns into attribute table column of ArcGIS?

Attribute tables in ArcGIS are not nearly as easily editable in comparison to something like Excel. For example, you have sorted the table based on some column value, and now want to fill in the ...
5
votes
1answer
495 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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3answers
9k views

ArcGIS 10 Python split string

I am trying to use Python to split a string field into three new fields at the separator " - ". The field is in the format "a - b - c". So I initially had this in the field calculator for newFieldA: !...
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1answer
4k views

Recording frequency of names in the attribute table?

I have a question with ArcGIS 9.2. In an attribute table the column [name] includes the name of every place in this layer. Next to that (in columns [numbers]) there should be recorded how often a ...
5
votes
2answers
321 views

How to calculate with time values in QGIS?

I have two string fields in a vector layer, "From" and "To", with values in the format of 10:16:30 and 10:18:00 e.g. I would like to calculate the difference in minutes as a decimal value, in this ...
5
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1answer
105 views

Field Calculator text field to new shapefile

I have point features being selected by a polygon feature and copied to their own shapefile. I also have certain values of the polygon feature being applied to the newly created point file. The ...
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4answers
1k views

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, AC...,...
5
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1answer
9k views

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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1answer
205 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 ...
5
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2answers
251 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 ...
5
votes
2answers
773 views

Why does ArcGIS Field Calculator expression unexpectedly return a binary value (0 or 1)?

I am running simple field calculator expressions and experiencing some of the silliest results I have ever seen. I am working on census data (living as a shape file) and trying to perform a simple [...
5
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1answer
3k views

Using Range in Python expression of ArcGIS Field Calculator?

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 :
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votes
2answers
106 views

Why can't I multiply values from column named 'length' using field calculator via PyQGIS?

I want part of my plugin to multiple value of length and add it to table.Basing on this question: How to use QGIS field calculator in python? , I made script that works fine for some filed: I can ...
5
votes
2answers
247 views

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 ...
5
votes
2answers
2k views

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 ...
5
votes
2answers
1k 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 ...
5
votes
1answer
823 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 ...
5
votes
3answers
167 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 ...
5
votes
1answer
48 views

Auto-generated field in ArcSDE for end user

The objective: Create a process where a coworker can open an .MXD, start editing, add a feature to represent a complaint, then add records in a related table to represent an inspection. Along the way, ...
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1answer
1k 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 ...
5
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2answers
3k views

Field Calculator does not notice selection? [closed]

I have a problem with the Field Calculator in ArcGIS 10. I selected specific points of a Shapefile I want to calculate, but FC is always calculating all fields. Unfortunately there is no checkbox in ...
5
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3answers
552 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 ...
5
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4answers
586 views

Is there a way to close a geoprocessing operation when the dialog box has been hidden/pushed to the back of the window

Is there a way to close a geoprocessing operation when the dialog box has been hidden/pushed to the back of the windows? I ran a python process as VB Script and when the error message appeared I ...
5
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0answers
43 views

How to update null geometries from an attribute [duplicate]

I have a large point feature class and have realised that there are several hundred features with null geometry. Fortunately the coordinates are stored as an attribute. So What I need to do is update ...
5
votes
1answer
171 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 ...
5
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0answers
232 views

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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votes
4answers
4k views

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, ...
4
votes
3answers
245 views

How do I say “use the value from the same row” in Field Calculator?

I have an attributetable with several columns. I want to change the values of column1 if they are NULL with the values of the same row in column5. case WHEN column1 is NULL THEN END How do I say "...
4
votes
3answers
12k views

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 ...
4
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3answers
4k views

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 ...
4
votes
1answer
3k views

Adding hyphen in ArcGIS Field Calculator to merge two 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 ...
4
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1answer
1k views

VB scripting in ArcGIS Field Calculator?

In my attribute tables field I am trying to get rid of the "&" in between names i.e. "John Adams & wife" and want it to say "John Adams and Wife" in all the attributes with "&". What is ...
4
votes
3answers
6k views

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 ...
4
votes
2answers
473 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 ...