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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695 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 ...
2
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1answer
437 views

How can QGIS Field Calculator sum values from a spatially joined table?

Can the Field Calculater be used to sum values from a related table via a Spatial Join? I have two vector polygon layers A and B, each with a numerical column VALUES. I want to update VALUES in ...
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1answer
32 views

Polygon shapefile field calculator problem

My project is set in WGS84 only, and I have checked 'enable on the fly'. I have created a polygon shapefile and my problem is that when i use field calculator in the attribute table on my polygon ...
2
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1answer
31 views

Create field on open ArcGIS map - not saved

I am using ArcGIS desktop with an SDE feature layer with enterprise data that I do not have rights to edit. The data changes weekly but I need a field that is sum of 2 current fields without creating ...
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2answers
200 views

Add both string and automated numbers in series to attribute table using field calculator

I would like to fill a column in my attribute table with an string that ends in a numeric value. Example: Object001 Object002 Object003 I would like to automate the process of filling in the ...
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1answer
407 views

QGIS field calculator expression: selecting min/max values within field groups

I am new to using QGIS (previously used Arc) and trying to get my head round the expressions and Python. I have series of polylines representing routes and require the linear distance from the ...
2
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1answer
704 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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2answers
197 views

Randomly choosing one from multiple fields in Field Calculator of ArcGIS for Desktop?

Using the Field Calculator in ArcGIS for Desktop, I want to randomly choose one field from a list of 10 fields (strings). The Excel equivalent, which is working, is: =INDEX(A2:J2;rnd()*10+1). How ...
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210 views

QGIS: Expression WHEN property1 = 'FOO' THEN property2 = 'BAR'

Our Foundation is adding additional properties to points. If property1 = FOO , then add property2 = BAR WHEN property1 = 'FOO' THEN property2 = 'BAR' END When I run this the ...
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1answer
505 views

How do I add a column in an attribute table using QGIS graphical modeler?

I have started to make a model in QGIS 2.2 graphical modeler. I have made a buffer around a polyline and used it to clip a polygon layer. So far i t works. But the next step is to add a new column ...
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2answers
154 views

What's the use of the buffer function in field calculator?

I'm trying to find out how the buffer command in the filed calculator works. I tried to create a new field to my point shapefile (integer) with the following: buffer ($geometry, 100) but no ...
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1k views

Field Calculator returning incorrect length and area values

I can get accurate lengths of line features and areas of polygon features using the "Measuring Tool" in a QGIS project. However, when I attempt to generate length or area data in Attribute Tables ...
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1answer
350 views

Batch Update Fields in Field Calculator or Model

I have a dataset of block-level census data that I clipped to an Illinois State Senate district. To update the data (e.g. for population) I'm applying an area multiplier, i.e taking the area of each ...
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1answer
466 views

How can I refer to a model variable in a Field Calculator or Pyculator formula?

I am new to QGIS 2.0.1 Modeler (Sextante) and not very able in Python programming. My question regard the use of field calculator (or advanced python field calculator) inside the modeler. Is it ...
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2answers
740 views

Is the derived area/length/xy values of a polygon/polyline layer in QGIS usable?

I have a raster that is projected to a state plane CRS and I am adding polygon/polyline shapefiles that are projected to WGS84. On the fly transformation is set to reproject to my raster CRS. When I ...
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2answers
67 views

How to flag parcels as being within stop type dependent distance of transit stops?

first question here! I have a parcel layer and a transit stop layer. The transit stop layer has different bus stops, light rail stops, etc. I want to add to my parcel layer attribute table fields ...
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2answers
386 views

How to calculate land cover inside the buffer zones?

In one Shape file I have created 1200 buffer zones Around coordinates. I created a field and calculated the buffer zones area in hectares. Then I clipped different landcover layers to the buffer ...
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2answers
1k views

Field calculator or update cursor?

I have a feature class in which one field (let's call it "Field_A"), as yet empty, is to be populated by the contents of another field ("Field_B") multiplied by a certain number (I'll call it the ...
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1answer
3k views

How to combine If Then with InStr in ArcMap field calculator?

I want to write an if then in field calculator that tests if a field in the attribute table contains one of several versions of another string (the versions vary by capitalization). Trouble is, I ...
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1answer
762 views

Why is using two imbricate UpdateCursor not working?

I hope my question is not redundant. I wrote a script to Update a table using two imbricate cursors. The goal was: to read a records, update some of its values Make a selection based on this ...
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1answer
1k views

Counting occurrences across a record in ArcGIS 10.0

I'm a student at Millersville University, PA studying for a BA in Geography with a concentration in GIS. I've stumbled across this site for questions I've had over the past year or so with getting ...
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2answers
3k views

Multiple input tables for Add Field in ModelBuilder

My model requires field1 to be added to fc1 and fc2, and then calculated according to a Python expression calc1. field2 is then added to fc2, and calculated using calc1. How do I add the multiple ...
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1answer
41 views

Field Calculator is not calculating selection from Make Feature Layer in arcpy

I am trying to use field calculator to calculate 3 different fields in python from a Make Feature Layer variable. It calculates the first field (MATERIAL_T) but then it doesn't calculate the second ...
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41 views

Finding and using mean and standard deviation value in field calculator

I am creating a field for a z-score of a particular attribute. This requires calculating the mean and the standard deviation for the attribute across all features. I've been using the statistics ...
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1answer
63 views

Rename cells in Attribute Table to 'XXX.$ID'

I feel like this should be easy to answer, but I can't get it to work for me. I need to edit the attribute table of a .gpx file before I load it into my GPS, in order to label the points. I can rename ...
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1answer
45 views

Using Arcmap to update a field based on data from another fields

I'm trying to update latitude and longitude data per individual station for a lab I'm working for. Here's some code I have that's supposed to assign any all bay stations of a certain name the ...
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2answers
72 views

type mismatch: 'esri_8' when using field calculator

I am trying to run the VBScript 'round' function using the field calculator on a column for a numeric field that contains a large number of rows (> 500k). When I run the code on a subset of the field ...
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74 views

Creating a weighted rating model/script for vector data

I'm using ArcMap and trying to create a model or script that can rate routes based on a weighted calculation of attributes. Right now the individual attributes don't have rating values which I could ...
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55 views

Passing Value for Dictionary Look Up in Field Calculator fails [closed]

I've a field calculator that I am trying to use that uses a csv file to look up appropriate value based on key that is passed provided to the function. As provided below, the only values calculated ...
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119 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 ...
2
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1answer
183 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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567 views

Cause of Field Calculator UnicodeEncodeError: 'ascii' codec can't encode character u'\xf6' in position 5: ordinal not in range(128)? [closed]

def Befahrung(value1,value2): if value1 is ' ': return ' ' else: return "G:\\Example\\" + str(value1) + "\\File_" + str(value2) + ".pdf" I try to create a field with a hyperlink. It works ...
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31 views

How to get Subtype name in Field using field calculator [duplicate]

I would like to get feature subtype name in another field using field calculator. Any one can advise to make this success? I am expecting ".Cal" file code using with Field calculator.
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2answers
300 views

How to trim strings in Field Calculator?

I am currently working on a County plat book and am in the process of prepping the "Owner_Nm" field that will serve as my annotation layer. I am trying to whittle down the owner names, based on ...
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0answers
32 views

How to save complex expressions in QGIS Field Calculator? [duplicate]

I have been debugging some long case expressions in the field calculator and getting frustrated because I have to remember to copy the expression before I test it otherwise I end up having to reenter ...
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3answers
1k views

Using python elif syntax in Field Calculator to reclassify a range of values from a different field and populate a new field

I'm trying to use the Field Calculator with a python elif statement to reclassify values from a different field and populate a new field, and while I'm not getting an error message of any kind, I'm ...
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2answers
760 views

Can anyone tell me why my field calculator is returning this error?

All I am trying to do is pull into a text field, a section of another text field via: fieldB = !fieldA![some_index:other_index] However I keep receiving the error below and I can't figure out why. ...
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347 views

Calculate field

I am working in ArcMap 10.2 and would like to calculate a field. The output should be the value of 'field 1' only if 'field 1' has a value 0 or it should give the value of 'field 2'. How to do ...
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4answers
5k views

Field Calculator: Add “0” to the front of all values in a column

I have a table for each state with Zip Code values. The 5-digit Zip Codes that start with "0" have been reduced to 4-digits. I cannot figure out how to add a "0" to the front of all the values in the ...
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3answers
140 views

Lists in field calculator in ArcMap?

Would anyone please indicate to me why this is not working. I am trying to convert all instances of '02ND' to '2ND' for example where some of the input fields (f1) are already converted and some are ...
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2answers
105 views

Field Calc to change one digit in a sequence Arcmap

I have an 11 digit ID in one field I'll call "Current_ID". I would like to create a new field named "New_Field" and populate it with same value except I need to change the value of the 4th digit from ...
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4answers
851 views

Python script for Field Calculator. ArcGis 10.2.2

I have a point shapefile with two columns i want to process. The first column is aspect and the second is aspect_m60, there is only one row with the aspect of my point. I have tried to write a script ...
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2answers
122 views

How can I do more flexible matching in conditional expressions than provided by LIKE?

With LIKE '%' works but I have had no luck with character ranges, i.e. [0-9] to match a digit. Oh for a regular expression ;)
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1answer
4k views

Delete first two letters from a string field

I'm looking for a field calculator python statement to delete only the first two letters of string entries. For Ex: !Name!.strip([0:2]) I know this syntax is incorrect. Thanks a lot
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2answers
494 views

Syntax error from Python parser of ArcGIS field calculator if then?

Using ArcMap - I would like to calculate one field based on the value of another field. I want to Update the field 'Date_Class' based on the value in another field 'MIN_YEAR_B'. I was trying to do ...
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4answers
4k views

Calculating acreage using ArcGIS Field Calculator?

What is the expression to calculate an acreage in USA ? I am aware that there is a geometry calculate but when you convert raster to polygon it doesn't do it's job and I have to use the field ...
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1answer
4k views

How to search text string and select item in QGIS?

I have a table attribute with complete roads name. I have to search items by digiting a part of the road name and I need to colour all the items selected. eg: ROAD NAME: / road 01 / road 02 / road 11 ...
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3answers
1k views

field calculator syntax error

I'm trying to calculate the direction the 'generate near table' function gives me into actual directions, N, NW etc. Azimuth would be a start too. I tried this script in the field calculator but it ...
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638 views

If/else statement in arcgis

I try to fill the fields with the condition if / else but it does not work. I do not know where is my mistake in the code. def TextValue ( !Classe! ): if !Classe! == "Steppe arbustive" or !Classe! ...
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2answers
65 views

How to add “0” to multiple parts of text value in Field Calculator with Python

I have values in a text column that are as follows: 000_100 100_200 ... 1000_1100 1100_1200 I want it to read: 0000_0100 0100_0200 ... 1000_1100 1100_1200 I want all values to have the ...