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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Calculate Field Syntax: If statement over many fields

Apologies if this has already being asked but I couldn't find a page pointing to this problem. I'm struggling with the python syntax in the Calculate Field so that, in the table above: if b, c, d, ...
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2answers
2k views

Use output of Add Field as input for Calculate Field in ModelBuilder

I have created a simple model in ArcGIS 10 which, after some initial processing of a feature class, outputs outputfc and adds a field to it. Regardless of the feature class input (which the user ...
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2answers
1k views

Force the decimals to use the comma in Field Calcuator ArcGIS 9.3.1

Can I add the comma "," to force the decimals to remove from the attribue and replace with the number? For example, I have an Acres field column that says 506320.0750 and I want to replace the decimal ...
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3answers
91 views

Calculate field using variables as fields

When I calculate a field like this: field_0="field_name0" arcpy.CalculateField_management("Layer", field_0, '!field_name1! / !field_name2!', "PYTHON_9.3") It works! The field "field_name0" in the ...
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4answers
1k 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 ...
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1answer
2k views

Using Python to Calculate a field

I am trying to replace values in a single column using an else if statement, but I keep getting an Syntax error in line 2. I'm new to Python so it's probably an easy solution, but I haven't been able ...
3
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2answers
5k views

Using conditional statements in Field Calculator

I have two fields, "P_Area" and "PC_Area", whose sizes I'd like to compare in a third field, "Areas_Equal". The "Areas_Equal" field should contain a "Yes" if the other two are equal and a "No" if they ...
3
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1answer
320 views

Adding an “m” to the end of every number in a row

What function do i need to use to add an space and an m after every item in a row, using the field calculator in the attributes table. I have a load of numbers (as strings) and would like to add m ...
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3answers
922 views

Auto-calculate field (area or formula)

I'm wondering if anyone has any insight into the potential to auto-calculate the value of a field, either area or distance (ideally) or a formula (based on the values of say 2 other fields, or an ...
3
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2answers
456 views

Python find string with two decimal characters

I have two columns in a personal geodatabase table that I'm trying to add up (to a third field) using a python function in field calculator, however some of the string values are not real numbers. ...
3
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2answers
841 views

Why is ICalculator.Calculate significantly slower than the CalculateField geoprocessing tool with SDE datasets?

I just discovered today that there are essentially two ways to calculate field values in ArcObjects: 1. Using ESRI.ArcGIS.GeodatabaseUI.ICalculator: ITable table = …; ICursor updateCursor = ...
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1answer
3k views

How to count and record the number of entities with the same name in the field calculator?

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 ...
3
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1answer
301 views

Using Python in Field Calculator to compare two fields

I'm trying to use field calculator to compare two fields in a table of tax parcel data, Land Value (LAND_VAL) and Improvement Value (IMPRVT_VAL). My goal is to determine (1) Parcels with land value ...
3
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2answers
101 views

How To Determine Percent of Matched Data?

In my attribute table, I have 2 columns with qualitative (categorical) data. Both of them are from different sources so I am trying to find the percent of matched data from these 2 columns. I created ...
3
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1answer
101 views

How to find lowest value that is not null using Python in ArcGIS for Desktop?

I have four fields in my table, (A,B,C,D). The field type is double with some fields being NULL. I used min(A,B,C,D) to return the smallest value and it works well if there are no NULL value in any of ...
3
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2answers
505 views

If-Then Statement in Field Calculator

Scenario: I have four fields: A, B, C and D Field A is text-based and contains values from '000' up to some number 'xxx' Field B contains a set of values (also text, but represented by numbers) ...
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2answers
69 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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1answer
121 views

QGIS - Is it possible to increase Output Field Name?

When creating a new Column, the default value for the length of the name is 10. Using the Field Calculator via the Model Builder, I want to include the names of regional areas into the columns which ...
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2answers
624 views

Adding VBA into a Python script generated by ModelBuilder

I have created a model that does a calculate field and have used VBA in the code block. But when I export it to Python, it doesn't work. Here is the VBA code: new_value = ...
3
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2answers
160 views

Expression to calculate and sort data from several layers into one layer

I am trying to develop an expression whereby one layer can add data from 2 other layers and then rank them, is this possible? I have also tried the problem with using just 1 layer but I cannot work ...
3
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3answers
475 views

How to create button that calculates acres on selected polygon features?

I'm looking to create a simple button that calculates acres on selected polygons and can't quite find what I'm looking for. I read through this thread: automating a python script..., but found it ...
3
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1answer
384 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 ...
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1answer
83 views

Using arcpy and script toolbox to add the date to a attribute table

I would like some information on how to add a date to an attribute table, by adding a user specified date in a script tool that will update the polygons attribute table. In short I have two polygons ...
3
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1answer
85 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: ...
3
votes
1answer
156 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
74 views

How to find and replace a singe word in a string?

How do i find and replace a single word of a string? e.g. Calle Iparraguirre to Iparraguirre I've tried: replace( 'Calle\\s', 'Calle\\s', '') replace( "name",'calle','') and all combinations ...
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2answers
123 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
votes
1answer
110 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
651 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
711 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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2answers
389 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 ...
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3answers
530 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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2answers
72 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 ...
3
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2answers
62 views

assign a number for each group in field calculator

I have several thousand features each of which has a name. The names are not unique. what I want to do with the field calculator is assign a number to each name so I can refer to a number and always ...
3
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3answers
97 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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1answer
1k views

Using the Field Calculator in a Domain field

I have a coded domain field with 10 dropdown options. Possible choices include integers and text. I need to change a selection of 250 features (which have differing values) to the same value. This ...
3
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1answer
1k 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
700 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
156 views

Calculate population coverage?

I am relatively new to QGIS and hope I explain this right. I am looking at the percentage of an population that has geographical access to healthcare. Therefore I have one shapefile with village ...
3
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2answers
571 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
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1answer
75 views

How to use QGIS field calculator in python?

I would like to use QGIS Field Calculator in Python to update the existing column based on certain conditions? How can I do this?
3
votes
1answer
108 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 ...
3
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0answers
110 views

How to calculate percentages using QGIS field calculator expression?

I am new to QGIS. I am wanting to calculate a field using other fields and some operators. Here is my expression: case When "RVM_CAT" = 'B' OR "RVM_CAT" = 'C' Then ("PC1" /100) * "RE_ha" When ...
3
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0answers
64 views

Can you use wildcards for column headers in Field Calculator?

I know you can use wildcards for fields like so (in the Field Calculator): case when "column" ILIKE '%example%' then 1 else 0 end Can you do something similar for the column headers themselves? I ...
3
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0answers
71 views

Warning 000405 when trying to calculate field [closed]

I am trying to create a model but am getting hung up on my first step. I need to calculate an ID field from an FID field so that I can join it to another table based on the ID field. So I have a ...
3
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1answer
79 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 ...
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0answers
69 views

Using Field Calculator to Convert Data Type In Field

I am trying to convert a field that is listed as "String" because it was imported into QGIS as a CSV (rural poverty population percentages by county in NC). I need to convert the percentages field ...
3
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1answer
67 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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0answers
289 views

Field calculator error [duplicate]

NOTE: This problem is similar to one that was answered here: Why does Field Calculator return 0 values when decimals are expected? I'm relatively new to python, and am trying to run a simple field ...
2
votes
3answers
376 views

Setting Zero values back to NULL

I'm working with ArcGIS 10.2 for Desktop and OS Windows 7. I need to set numeric vales from Zero back to NULL, but I can't from the field calculator. I'm working with a vector file and I need to ...