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.

learn more… | top users | synonyms

8
votes
5answers
303 views

Print out the properties of the attribute table in qgis?

I have to merge a lot of shapefiles into one great shapefile. So I want to compare the properties of the attribute tables to see if there are differences between the tableproperties of each shape ...
0
votes
1answer
56 views

Can QGIS report/calculate areas/perimeters of individual polygon components within multipart shapefile?

Can QGIS report/calculate the areas/perimeters of individual polygon components within a multipart shapefile without using the "explode" vector tool to generate a new file? using QGIS 2.2.0 on ...
0
votes
0answers
118 views

ArcGIS Python Field Calculation

Ok so i've got a problem with the field calculator in ArcGIS: I'm already pretty far with it since i got some help :P but it still doesnt work. What i've got: -A complete table of several states of ...
2
votes
1answer
194 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 ...
1
vote
2answers
98 views

Calculate field based on most frequently occuring text/value in other fields in attribute table (ArcGIS)

I was wondering if anyone knows if it is possible to calculate a field based on the most frequently occurring value in other fields. What I have is 5 fields with crop information over 5 consecutive ...
-1
votes
1answer
130 views

Error python calculation in field calculator

In a shapefile, I have Field named Elevation with a text field containing integer ranges stored as strings: 1 - 2 3 - 6 2 - 3 8.5 - 12 11 - 12 I need to categorize it using rule that if Elevation ...
1
vote
1answer
24 views

Does ArcGIS Desktop have conditional function useable in field calculations?

Does ArcGIS / ArcView 10 have a conditional function, e.g. ifx(test,if_T,if_F), that could be in-lined in field calculations?
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 ...
3
votes
1answer
311 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 ...
0
votes
1answer
204 views

Calculating Stream Length-gradient Index (Hack Index) with the field calculator

I'm trying to calculate the Stream Length-Gradient Index of a stream (example data below). Just started to get into python, but am struggling with a solution to this problem. I have 42 streams to run ...
0
votes
2answers
156 views

Model Builder Error populating attributes with Calculate Field

I would like to run a model that iterates over all feature classes in a feature dataset and uses the feature class name to populate an attribute field (see model below). However, when running the ...
3
votes
1answer
448 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 ...
0
votes
0answers
62 views

Field Calculator: Error message

Field Calculator: using the x- or yat or (0 "or-1" ) expression, I keep receiving an error: An error occurred while evaluating the calculation string: Index is out of range. I have shut down and ...
2
votes
0answers
28 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 ...
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 ...
1
vote
2answers
68 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 ;)
1
vote
2answers
76 views

Iterate through each county in a shapefile, select the county and make a second selection by location - modelbuilder

The goal of my project is to create a table with two fields. The first field showing a county name and the second field listing every county that touches the boarder of the county listed in the first ...
2
votes
2answers
122 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
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
votes
2answers
68 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 ...
1
vote
1answer
49 views

Use field calculator in QGIS so get number of points in polygone and store it in attribute table

I have to layers, one point one polygon (with 6 areas) stored as shapefiles. Now I want to count the number of points in each area and write it into the attribute table of the polygons. A column ...
3
votes
1answer
94 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 ...
4
votes
3answers
296 views

How to find/replace element in field with Field Calculator

I just want to perform the following operation done in Matlab into the Field Calculator using Python: p(p==0) = 0.001 ; p(p == 1) = 0.999; tVar = .5*log(p ./ (1 - p)) the operation consists of a ...
3
votes
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 ...
0
votes
0answers
105 views

New values created with QGIS field calculator become null upon saving

I'm having a problem with QGIS. I'm trying to create a new column in the attribute table for a shapefile. The numbers in the fourth column (see screenshots) are currently strings, so I want to convert ...
1
vote
3answers
358 views

How to Convert a Number to Percentage in Field Calculator

Using ArcGIS 10.2 and Personal geodatabase,I have a field with values of Numbers like 0.461538 and Type of "Double" can you please let me know how I can Export them to new Field in Percentage Format ...
3
votes
3answers
2k views

Basic If/Then in ArcGIS 10.2 Field Calculator (Python or VB)

I've been looking through these threads and can't seem to figure out my answer yet. Very new to VBA and Python, but lots of years with Arc.I know I can do this the slow way with Select By Attributes, ...
1
vote
2answers
166 views

How to add a new column in attribute table with attribute with indexes of another max-min ordered attribute field?

I've an attribute column named e.g. VALUE with different values I would like to make a column named e.g. ORDERsuch that the greatest value has the attribute 1 the second value 2 etc. etc. so order ...
1
vote
1answer
94 views

Problem in long expression in field calculator

I am trying to compute the following expression with Field calculator. The input table values are around the size of this value: 562643580,7843, and the field name (the field of destination) is: ...
2
votes
1answer
225 views

How to make autoIncrement number start with (001…009, 011…099)?

i have a challenge with my time in my work, i have feature class called "Parcel" storing many data, i generated an autoIncrement number by using field calculator, in field "parcel code" Expression: ...
2
votes
1answer
163 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 ...
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. ...
0
votes
0answers
61 views

Bug in Qgis 2.0 Field Calculator with Values from Joined table

I have a data of hospitals. I have two excel sheets, one has no of patients examined in each hospital and other has no. of patients treated in each hospital. I want to find percentage of treated ...
4
votes
1answer
84 views

Are Date columns in feature classes stored as python datetime objects?

I have a Date column called readings_measurement_tstamp stored in my feature class. I would like to add a String column to this feature class and Field Calculate it to be be just the %H:%M:%S ...
0
votes
0answers
60 views

Populate a new field with list of the top 5 values of all fields for that record

I have 15 fields. I would like to add a new field that is populated with the field name and value of the top 5 highest values of the 15 fields for each record in the table. The new field would be a ...
5
votes
1answer
62 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 ...
1
vote
2answers
467 views

How to fill attribute field of one feature based on calculation on attribute field of another feature

I would like to fill an Attribute field of a geodateabase table based on some calculations such as 'sum' over specific field of another Feature class. Is there an Approach to formulate it? while in ...
1
vote
1answer
60 views

Mismatch in area calculation using Field Calculator vs Group Stats in QGIS 2.0

I have two polygon files (A being my area of interest and B being a categorised land cover layer). Both layers were in the same projection (projected and not geographic). Using QGIS 2.0, I used the ...
0
votes
0answers
14 views

Unique referencing based on Co-ordinates

I have a list of 400 nodes, all split across 'maps' which are gridlines 1000x1000m. Each grid area is referenced by the first 3 digits of the X value of the centre and first 3 digits of the Y value ...
3
votes
1answer
181 views

Can't compute area of shapefile in field calculator

This shapefile represents the counties of NM. I am trying to compute the area of each polygon (yes, I know there is an area field, but this is a simpler example of a problem I'm having which doesn't ...
3
votes
3answers
2k 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 ...
0
votes
1answer
130 views

Field Calculator - replace string function - data value recognised as a column and is “not found” [closed]

I have the same challenge as GrahamD - Field Calculator - replace string function I have exactly the same challenge. Exactly the same as GrahamD's challenge, p abbreviated for pan. Type_2 as a test ...
0
votes
2answers
181 views

Field Calculator - replace string function

Within an attribute table I'm trying to replace one string with another using the 'replace' function . As an example, there are a number of features whose field 'NAME' contain the string '(B)' and ...
4
votes
2answers
78 views

How to replicate trunc function on QGIS?

I've search a bit before asking this question, but I haven't found the answer. Is there a Trunc function on QGis? I've tried using floor, but it doesn't work (like I want) if the number is negative, ...
1
vote
1answer
133 views

Is there a way to automatically calculate attribute values for new features?

I am creating a vector point layer which will be added to over time. I have been using the field calculator to populate fields such as X and Y coordinates. I'm wondering if there is a way to have ...
2
votes
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 ...
3
votes
2answers
342 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) ...
0
votes
1answer
96 views

Is it possible to calculate a value based on values of another row?

I have a point shape file in qgis. For one of the attributes, I would like to offset the values, i.e. the value for point 1 goes to point 10, the value for point 2 goes to point 11 and so on. I see ...
2
votes
1answer
73 views

Populate an attribute table field using the 'startswith function

I am hoping that someone may be able to help me. I am new to ArcGIS, and even newer to Python. Working in ArcGIS 10.1, I have done is created a new text field in an attribute table, which I have ...
4
votes
2answers
138 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 ...