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)

3
votes
2answers
2k views

Populating field with max M value of feature using Python in ArcGIS Field Calculator?

I need to calculate the max M value for a line feature using Python in ArcGIS 10 Field Calculator but I cannot figure it out. In 9.3 I used the follow VBA expression… **Pre-Logic VBA Script Code:** ...
3
votes
1answer
43 views

Replace non-ASCII characters in QGIS Field Calculator

I want to replace all non-standard characters from fields in a dbf table in QGIS. From http://stackoverflow.com/questions/20078816/replace-non-ascii-characters-with-a-single-space I see we can use ...
3
votes
2answers
38 views

Name of field in ArcMap Field Calculator window

A few days ago I was answering Comparing two fields and printing result as 1 (if number matches) or 0 (if not) using Python Parser of ArcGIS Field Calculator? When describing the process required ...
3
votes
1answer
104 views

QGIS Field Calculator functions

Using QGIS 2.12.3, within the Field Calculator "Geometry" section, there are certain functions, such as "area", that also have a corresponding term beginning with a dollar sign, i.e. "$area". I don't ...
3
votes
2answers
67 views

Why is VBS If Then Label Expression not working?

I am trying to label a field based on other field. For [TYPE] = "PRIMARY", the [LABEL] is having this structure: "TAN80901B" For [TYPE] = "SECONDARY", the [LABEL] is like this: "TAN80901C/D20b" I ...
3
votes
1answer
102 views

Reclassifying a polygon using ArcGIS field calculator?

I am trying to reclassify a polygon into three classes: 1 and 2 = 5 3 and 4 = 3 5 = 1 I have been trying to do this by calculating a new field in the attribute table but I am very ...
3
votes
2answers
185 views

Which python function should I use to populate a string field based on a numeric value from a numeric field in ArcGIS Field Calculator

I am new to Python and I'm trying to write a simple if then statement in Field Calculator in ArcGIS 10.2.2 that will take the values from a numeric field and add them to a string field. I can't ...
3
votes
2answers
221 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 ...
3
votes
1answer
2k views

How to summarize a column in QGIS field calculator

I have data with a column containing a number value, and I want to divide the value of each feature by the total sum of all the values in the column (to get a percentage). So I would like to know if ...
3
votes
1answer
1k 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 ...
3
votes
3answers
2k 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
2answers
304 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
votes
1answer
132 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
votes
1answer
2k views

How to copy values from field to another using arcpy?

Can some one please let me know how I can do simple field calculation like Copying From "A" to "B" in ArcPy? I have found lots os example on web which they all used extra expression and they were ...
3
votes
3answers
833 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
votes
1answer
595 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
votes
1answer
47 views

How to convert a “yyyy/mm” field to “yyyy/mm/dd”?

I am trying to edit an existing date field of the form "yyyy/mm" to a format that the TimeManager Plugin for QGIS can handle - I guess "yyyy/mm/dd" will do it. I've got as far as opening the ...
3
votes
2answers
100 views

Using ArcGIS Desktop field calculator (python) to parse date

I'm trying to parse a datetime field using python (but have never used python for it before). I have a field that contains a valid date, but not a valid time... and other fields that have valid hour ...
3
votes
1answer
75 views

QGIS field calculator returning results in different units?

I am trying to use QGIS to get the perimeter, area, bounds width, and bounds height of US congressional districts, using the US Census TIGER shapefile. I loaded the shapefile into QGIS, set my CRS to ...
3
votes
1answer
50 views

add text value to attributes

this is a novice question I have an attribute field that's missing a piece of information, i'd like to amend the attribute field like below: This is the current attribute field: "V:\Building & ...
3
votes
2answers
117 views

Field Calculator Script

I am looking to check how up-to-date a feature class is by using our latest parcel update. I am wanting to check "owner" field with "Owner_1"...I am using field calculator to grab the last name in ...
3
votes
1answer
272 views

Accumulating values of date field using Python parser of ArcGIS Field Calculator?

I would like to modify the following accumulative/sequential python code sample in field calculator in a Date Time field. I think this is the correct code to use but let me know if not. The Date Time ...
3
votes
1answer
404 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
votes
1answer
197 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
502 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 ...
3
votes
1answer
177 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 ...
3
votes
2answers
170 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
1k 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
votes
2answers
4k views

Using Value from Iterate Feature Selection to Calculate Field in ArcMap 10.1 ModelBuilder

I have two polygon feature classes, an alignment layer and a parcels layer. I am trying to use ModelBuilder to create a tool that will do the follow: iterate through groups in a single field of a ...
3
votes
2answers
500 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
votes
3answers
830 views

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

How do I append my field values in my .dbf to correspond with the values of my feature's attribute table. I need to append 0's to the field value if the field value is less than 11 characters in ...
3
votes
1answer
68 views

QGIS find and then replace value in multiple columns

This is based on a previous question/answer that I had. QGIS -replace values in multiple columns I need it to update 3 fields now and I get an name 'e' is not defined error. What have I done wrong? ...
3
votes
1answer
37 views

Conditional Statement in QGIS Field Calculator

I'm using QGIS to calculate total loss in an earthquack attack. I wrote this expression in Field Calculator. CASE WHEN "build_type" = 1 AND "MMI" < 5 THEN "perc_loss" = 0 WHEN ...
3
votes
1answer
72 views

Calculate area of geometry derived from current feature in QGIS 2.8

I'm trying to create a new field defined as the area of the convex hull of the current feature, in the Field Calculator in QGIS 2.8. Calculating the area of the current feature is easy ($area), and ...
3
votes
1answer
38 views

How to replace a directory using QGIS Field calculator?

I have a column called Hotlink full of incorrect directories and I need to edit them. They currently read C:/ABCD/filename.pdf and I want them to read C:/Maps/ABCD/ABCD/filename.pdf The script I'm ...
3
votes
1answer
46 views

QGIS - Field Calculator: scale_linear gives unexpected result

When I try to use scale_linear, its output isn't as I expected. My values are from 1 to 16, so I set domain_min = 1 and domain_max = 16. I want to interpolate to interval from 1 to 4 so I set ...
3
votes
1answer
768 views

Why is arcpy.CalculateField_management() writing 1899-12-30 00:00:00 instead of expected date?

I'm using ArcGIS 10.3.1 for Desktop to test before writing an answer to How to enter date with arcpy.GetParameterAsText with arcpy? I have written the test code below that I am running against a test ...
3
votes
2answers
380 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
votes
2answers
124 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
votes
3answers
124 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
votes
1answer
3k 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
votes
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
votes
3answers
1k 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
votes
1answer
487 views

Sum up area left “underneath” polygons in QGIS?

I have an area shape layer and multiple other area shape layers. Now I would like to calculate how much space (square kilometers or percentage of area) of the polygons of this area layer is NOT ...
3
votes
1answer
1k views

calculate value using maximum value from different feature class

I'm trying to get the maximum numeric value from one feature class and use that value in an expression to calculate values of a different feature class. fc2.bldg_id = max(fc1.bldg_id)+1 Can this ...
3
votes
1answer
33 views

Tiny difference of calculated area of polygons

I have a shapefile of about 62.000 polygons. I calculate the area of each polygon on a field, named AREA1, with Calculate Geometry option. Secondly, I create a new field field named AREA2. I calculate ...
3
votes
1answer
23 views

QGIS: Error message in query builder

I am using QGIS version 2.14.1 (Essen) and trying to update data in my table using field calculator. I am inputing the following statement: update "table_1" set "table_1" ='y' where "table_2" ...
3
votes
2answers
65 views

Field Calculator - conditional function and string variable?

I know this question has been asked before in different fashions, but I can't seem to get my python script to work despite looking at all the relevant questions I could find. I am simply trying to ...
3
votes
2answers
41 views

Using Field Calculator vb to check for name with /n in the string?

I am calculating values for a field (Score) based upon the names from another field (Modified). One name is "blaugh\nblaugh". Field Calculator keeps treating the name as having a new line command. I ...
3
votes
1answer
213 views

Add comma to number labels, multiple records in attribute table

A QGIS question: How can I insert commas in 4 digit numbers in an attribute table that has multiple records, with some numbers that are only in the hundreds? It's for an animation so multiple labels ...