Field calculators (which are available in QGIS, ArcGIS-related products, etc.) can recalculate the values of a single field, on all, or selected records within a table based on a symbolic expression.

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320 views

Measurement units not returned in project CRS units

I am attempting to calculate area of country polygons using the field calculator. The layer in question is unprojected WGS84, but I have set the project CRS to World Equidistant Cylindrical ...
3
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2answers
100 views

ArcGIS 10 Field Calculator [closed]

I'm new to GIS in general and field calculator in particular. I have a basic attribute table with three columns. I'd like to assign values to column C based on what is in column A. If Column A = 8 ...
3
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1answer
93 views

Field calculator uses wrong fields when working with joined data

I am having an issue in qgis table joins. i have a joined a csv file to a sqlite database and common id is used for join. the join is displays correctly in attribute table. the attributes in sqlite ...
3
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1answer
485 views

How to use the field calculator's centroid() Geometry function in qgis 2.0?

There is an option in the field calculator for centroids under geometry which when you double click gives you "centroid( ". What information is required here in order to use this function?
3
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1answer
413 views

Calculate Field python code has “Expected end of statement” error

I am creating a line shapefile from a csv in a Python (2.7) script. I am assigning an ID field from the csv to a variable and then later using it in the Calculate Field tool. The ID field originally ...
3
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1answer
837 views

Why does Field Calculator return 0 values when decimals are expected?

I realize I posed this question, and got answers, several days ago (see (Field calculator error)) , but none seem to really be working, and so am posing again. Below are two screenshots that show the ...
3
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2answers
342 views

QGIS Field Calculator Results Removed When Saving Edits

Mac OSX 10.6.8 QGIS 1.8.0 : Using the field calculator from the attribute table, the $area of each feature is shown nicely in the table until I try to save it, then all the values are replaced by NULL ...
3
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3answers
432 views

How to make Field Value constant size(length) by appending zeros towards the end?

I have been racking my brain, but I can't seem to find a solution to appending my field values in my .dbf to correspond with the values of my feature's attribute table. All I need to do is to append ...
3
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3answers
86 views

Field calculator problem

I have an issue withe the field calculator. It is impossible for me to multiplicate 2 columns (area * KZ). The result is always "0". I used the formula area * KZ....is this the right formula? LINK to ...
3
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2answers
208 views

How to create a label formatted like “ 1,000' ” from a numeric field?

This question builds on a previous question I came across at gis.stackexchange: How to easily edit attribute data using Regular Expressions? Perhaps someone can point me in the right direction? I ...
3
votes
1answer
966 views

How to use field calculator from QGIS Sextante plugin

I am trying to use the Sextante field calculator to calculate a field for a buffer radius using a categorical text field. The formula works fine when I run it using the standard QGIS field calculator ...
3
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3answers
605 views

ArcGIS Field Calculator Python numbering rows of fishnet

I have a grid of 100*100 cells. I want to add to each cell a number representing the row it is in (like in excel). I added a field and want try to solve that with field calculator: The code is ...
3
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1answer
460 views

Syntax of conditional statements in QGIS Field Calculator(s)

I have a shapefile which I need to modify. There is one column "CLASS" with the attributes: "A", "B" and "C". I need to change "A" into "1!, "B" into "2" and "C" into "3". I tried it with case when ...
3
votes
1answer
255 views

Is there a (better) way to debug Visual Basic Code Block in calculate field using ArcGIS?

From time to time, I have to use Visual Basic in Calculate field. As the code get bigger, the more complicated is to debug it. And ArcGIS (9.3) does not help as the error messages are, in the best ...
3
votes
1answer
63 views

How do I add a field to a table using the QGIS graphic modeler?

I was wondering if anyone could help as I'm struggling to get anything out of the QGIS graphic modeler. For info I have no programming skills whatsoever. I need to be able to add a new field to an ...
3
votes
1answer
313 views

How to Populate new field using expression containing MAX value from another field in ArcGIS attribute table using field calculator?

I've got one field X with 10 numerical attributes (float/double). I've created a new field Y (also float/double) which I need to populate with the percentage of each record/attribute (in each of the ...
3
votes
1answer
60 views

Do pad functions of QGIS Field Calculator have bug?

I have this expression in the field calculator: regexp_replace('1', '^(\\d+)', rpad('\\1', 3, '0') ) gives 01 rather than 001 as expected. the *pad functions work fine when called outside ...
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2answers
189 views

Round decimal number in ArcGIS10.1

How can I round the decimal number in a table in Arcmap: e.g. how can I set it to 2.60?
2
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3answers
126 views

ArcGIS 10.1 : Returning shape.area in my code block

I try to calculate a field using an 'if' statement in the field calculator. Here is my code : " #Expression MyField_2 = def Reclass(!MyField_1!) #Parser Python 9.3 #Code Block def ...
2
votes
1answer
344 views

Why does this python function return a value of 0 in field calculator?

I am trying to calculate the percentage of a total which the median value makes. I have a column with the median column labelled (i.e. 1st,2nd,3rd,4th column is median), the columns of values and the ...
2
votes
3answers
475 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 ...
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2answers
399 views

Why is QGIS Field calculator button greyed out?

I'm using QGIS to attempt to calculate the area enclosed by a set of points that I have capture used a GPS device. I have imported the coordinates from a CSV but when trying to open the field ...
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2answers
754 views

FIeld calculator gives integer not a real as requested

Two fields "population" and "F06_popula" (both integers) were used in calculating a new field pct-diff. I asked that the new field be a decimal with a width of 10 and precision of 3. The result has ...
2
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4answers
3k views

Basic Field Calculator help

I have no experience with Field Calculator in ArcGIS 10. I have a very simple calculation I would like to perform that I could do easily via pure SQL but just can't seem to get my head around it in ...
2
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2answers
131 views

Updating column in Field Calculator using values of another column?

I am very new to GIS, so I hope to get some help. I am using ArcGIS 10.2 for Desktop. I want to create a new numeric column on my attribute table to store "seasons" in numbers. For example, I want ...
2
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1answer
144 views

ESRI File Geodatabase with a field calculator with an incrementing number

I've got a python script that runs on the Field Calculator of a ESRI File Database. Right now it runs correctly in that it will increment the last three digits of the value. But this is a script ...
2
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1answer
197 views

How to return absolute values using ArcMap field calculator?

I have a field of number ranging from -50 to 50. Is there a way using the ArcMap field calculator to populate a field with all of these standardised (positive numbers) so I have a range of 0 to 50 ...
2
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4answers
129 views

Field calculator Python else statement question

The codeblock below is run on Field1 and calculates Field1 to equal Field2 if they are not equal. Else it returns Field1. My question is, does the else statement actually recalculate Field1 to equal ...
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3answers
750 views

Python and CalculateField

I am having trouble with using Python together with my gp.Calculatefield tool in my python script, and I am not sure why.. Heres the code (UPDATED) import arcgisscripting, os, sys myTempWorkspace = ...
2
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2answers
481 views

Looking for python/VB script to insert a new uniqe field

Is there any phyton/VB script which will add a field to shapefile which will be corresponding to first three characters from the shapefile name ? I am working in modelbuilder and arcgis 10. Thanks ...
2
votes
1answer
2k views

How to set the value of a field in all selected rows of a table using ArcGIS 10

I have an attribute table in ArcGIS (it's large - around 300,000 elements). I've selected some rows of the table using 'Select by attributes' and I want to set the value of a field for all of those ...
2
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1answer
101 views

How to get the First and Last Point coordinates of a Polyline with Field Calculator in ArcGIS10

I'm trying to get the First Point coordinates (x,y) and Final Point coordinates (x2,y2) from a polyline in ArcGIS 10 with the Field calculator. I've added 4 (double) fields like StartX,StartY,EndX ...
2
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2answers
113 views

Comparing 2 fields using Python

I am trying to compare 2 fields(double) using python. I want to round to the nearest 10th and flag those with a "1" that are not equal. Here is what I have at the moment: def Qcontrol(old, new): ...
2
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1answer
127 views

Field Calculator: return two or more field value

I trying to return three field values in same If Statment and conecate them, but i Get NULL value insted of the conecated fields getClass (!InDiameter! , !OutDiameter! , !TheridDiameter!, ...
2
votes
1answer
54 views

How can I change all the entries in a field to be entirely lower case?

I have a field with a bunch of species names, but for a single species there a bunch of case combinations (e.g. Cat, CAT,cat). I want to make a new field which has all the entries in all lower case. I ...
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2answers
111 views

Field Calculator, Conditional

I am trying to assign Value from one field of my Attribute table to a new field based on the 3d field.... The Code Block I am thinking about as follows: *def conditional (!FarmCateg!): if ...
2
votes
1answer
78 views

Extract characters inside parentheses in QGIS

I have a shapefile of the buildings on my college campus. It has a "name" field that includes the name of the building and then in parentheses the building's campus address (i.e. Health and ...
2
votes
1answer
337 views

How to use Field Calculator to calculate area as percentage?

I am searching for python code to use in Field Calculator to calculate area as a percentage in relation to another field? The area percentage needs be calculated based on the total area for each ...
2
votes
1answer
231 views

Calculate field result is float with Arc tool, integer with arcpy script

I am trying to calculate a field for some points within a python script using arcpy functions. (This is calculating the percentage visibility from a cumulative viewshed, if that matters.) # Process: ...
2
votes
2answers
419 views

Type mismatch error in Calculate Field tool in ArcGIS 10.1

I'm trying to run a rather lengthy model (built in ArcGIS 9.3.1) in ArcGIS 10.1 and I'm recieving an error on a Calculate Field tool. The error is - Type mismatch: 'iif'. This error is refering to ...
2
votes
2answers
554 views

Trimming Specific Text Values in QGIS Field Calculator

Sorry if this is a dumb question, but I am wondering if there is a way to copy the text from one field to a new field, but eliminate specific words. For example: **Old Field** ...
2
votes
1answer
39 views

How to return end of string up to a certain character using Field Calculator?

I am trying to accomplish this task: http://stackoverflow.com/questions/15851568/how-to-get-the-last-part-of-a-string-before-a-certain-character within the Field Calculator. I have the below but ...
2
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2answers
144 views

Convert from Julian Date to Calender Date in Field Calculator

Does anyone know of a way to convert from a Julian date to a regular calender date in either QGIS or ArcGIS field calculator? Thanks...
2
votes
2answers
98 views

Conditional field calculator expression

I need to calculate the PIPEID field to equal the G_KEY_COMP field if PIPEID is null or PIPEID and G_KEY_COMP do not match. I think the first condition of the PIPEID being null is covered by the ...
2
votes
3answers
119 views

Calculate Field tool to calculate on null fields

I'm using ArcGIS 10.1. I want to use the calculate field tool in ModelBuilder on a table where if field1 is null, it should take the value of field2. If field1 has a value then it should stay as is. ...
2
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3answers
90 views

How to write FIDs of points within each polygon to polygon field?

I have two feature classes one with points one with polygons (in ArcGis 10.2). Now, I want to write into a String Field of the polygon layer a list of all the Point-FIDs that are within each polygon ...
2
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2answers
208 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 ...
2
votes
1answer
348 views

Am I over-complicating adding and then calculating fields? Suggestions for a better way? (Python)

I'm attempting to re-position a question I asked yesterday here. I am starting to think that the way I wrote my code just isn't the best way. Am I overcomplicating things? I know for a fact that ...
2
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1answer
440 views

Field Calculate Degree Minute Second in Different Format

I have a field that is in degree minutes seconds, populated from ET Geowizards COGO Inverse tool. It populates the values as 90-12-28.15 where 90 is the degree, 12 is the minutes and 28.15 is the ...
2
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1answer
432 views

Field Calculator operation is not working

I've done this 100s of times and I can't understand why it won't work! I'm trying to copy the first 8 digits of from a HUC 12 (Hydrologic Unit Code) to a new field, which represents a larger ...