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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2
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4answers
100 views

Calculate Length Totals in ArcGIS based on field values

I am having trouble finding the right words to describe this problem but here goes: I have 3 values (120,270,380) in my field called operatingvolt for every segment of conductor. Each segment of ...
1
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2answers
93 views

Calculate field more wisely

I first classified firstCol into groups and then I want to give the groups with different weighted values in another field, SecondCol. I will need to give different weighted values very often. I find ...
10
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2answers
1k views

Computing new attribute based on changes in another attribute using ArcGIS Desktop with Python?

I am attempting to classify a set of gps time-encoded point data into behaviors based on different attributes. I have created an attribute that is 0 for home and 1 for away based on location, and ...
15
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6answers
6k views

Find/Replace Double Quotes using Python Parser of ArcGIS Field Calculator?

I'm trying to use the Field Calculator (ArcMap 10.0) to strip out double quotes in an address field (I didn't put them in there, believe me). I've tried many incantations but am still unable to even ...
7
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1answer
10k views

Adding automated values to attribute field?

I have parcel and buildings layers. In their attribute tables I want to replace "NULL" values with numbers from 1 to 2000, in "Parcel ID", or "Building ID" field. How can I do this in ArcGIS ...
0
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1answer
601 views

Adding sequence numbering based on attributes in table? [duplicate]

Is there a way to auto populate a sequence of numbers based on another attribute in a table? For example, if field "Name" has a sequence of numbers from 1 to 10, and I want to number all the rows in ...
1
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1answer
39 views

Calculating average values of condition or receive values from a table for calculation in another table

I have a table with data (in this example the field "TSS"), a field time corresponds to the data for each point. I want to create a field with the mean values for each point all time values, without ...
1
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1answer
4k views

Concatenating fields using VBscript in ArcGIS Field Calculator?

I'm trying to get one column of text to move into another column that already has text. I DON'T want to replace it, I want the transferring text to be added to the already existing text in a shp file ...
2
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3answers
150 views

If else if in ArcMap Field Calculator (Python)

Help! I think I am missing something that must be so obvious but I cannot figure out what I am doing wrong. Here's some background: I have one short integer field (MajAspNum) that has values 1-10....
2
votes
4answers
98 views

IF else statements arcmap, using python

I have a shapefile with a number of fields. I have one field (let's call it Field A) that I need to populate based on another field (let's call it Field B). If Field B is greater then 0 I need it ...
0
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0answers
30 views

Calculate field for each Feature Class in Dataset using Python and different arguments

I have Dataset with Feature Classes in it. I'm building this in ModelBuilder. I want to calculate new field (SMB_ID) depending on attributes for each feature class. I was trying to make it simple ...
2
votes
1answer
85 views

QGIS processing toolbox: fieldcalculator - update only selected features is not possible

I am working on a model where I need some calculations on only some selected features. In the normal fieldcalculator you can check 'only update ... selected features'. When using the fieldcalculator ...
3
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1answer
49 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 ...
2
votes
1answer
106 views

Running ArcGIS field calculation using Python with algebraic expression using other field values as variables?

I'm trying to run a field calculation using multiple fields in a table as well as independent numeric values with python code in the field calculator window. I've included the first 7 lines of the ...
2
votes
1answer
75 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 ...
1
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2answers
70 views

How to compute the distance from the current polygon centroid to another in QGIS field calculator?

There is layer with polygons. I want to save in new field distance of every polygon's centroid to centroid of one particular polygon. To do this I should write some expression like this: distance(...
2
votes
2answers
90 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 ...
3
votes
3answers
84 views

Can't replace attribute with field calculator

I have an attribute table where one of the columns (laeskaerm) has been edited/created by checkboxes on 2 different machines. Result: it contains both 1, 0, true, false and NULL I'd like to replace ...
3
votes
1answer
3k views

Selecting by attribute and calculating field of new selection in ModelBuilder?

I have a polygon shapefile (with 4000 records in it) that I want to group into different regions by doing a "select by attribute". I need to do this about 164 times because of the different selection ...
1
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1answer
65 views

How to edit virtual field definitions in QGIS?

I have a virtual field in QGIS. The values are updates depending another column with a concatenate CASE statements. I would like to edit this statement but I cannot see it. I have attempted to use ...
2
votes
1answer
126 views

Using ArcMap Field Calculator to count number of identical values?

I have a file with an attribute table with data in 3 columns, and would like to use field calculator to populate a 4th column. The data is integer numbers between 0 and 56. I want the new column to ...
1
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1answer
65 views

Polygon Surface Area Calculator in different map projection(s)

I'm simply looking for an online tool or a utility to calculate the surface area of the same polygon (i.e shapefile) in different projection (projected and geographic projection system) systems. It ...
-3
votes
1answer
51 views

Calculating field gives invalid expression in QGIS?

I am a new user of QGIS and I want to add a new field in my attribute table named densite which can be calculated by POP(population) / Area, in Field Calculator, I wrote POP/Area no result !! invalid ...
4
votes
2answers
908 views

Calculate average value for each row

The picture is an example, but the method would be the same at mine bigger dataset. So i have some parcels with each a ID value and some fields. such as field 1, field 2, field 3, fieldd 4,... with ...
2
votes
3answers
56 views

Add value to entire column in attributes

Is there a way to add a value to the entire column? I don't think i can use raster calculator because it's a text i want to add, the letter "B". Here is a picture. This is what happends when i use ...
4
votes
3answers
4k 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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1answer
28 views

calculating sq ft of an picture image with only a scale bar as reference

I have an architectural image of a building. However, I had to change the blueprint and extend the walls out further increasing the total sq.ft., and simply for the means of drawing out the new ...
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0answers
61 views

Calculate z score into new field in ModelBuilder? [closed]

I'm trying to calculate z scores for a given column. I am working with a shapefile, that contains fields like percent poverty, percent tree canopy and temperature. My ultimate goal is to add new ...
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1answer
863 views

Deriving Z-score values for given field using ArcGIS for Desktop?

I have a shapefile with an attribute field with a range of numerical values. How do I derive z-score values for this field using ArcGIS for Desktop?
1
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1answer
46 views

failed to Writing conditional (if/then) statements into Field Calculator of ArcGIS for Desktop using Python parser?

I wrote this following several examples but it is still wrong. I need to populate a new field based on 5 ranges of values. def marks(Wards for try.JHRatio ): if (Wards for try.JHRatio <= 50)...
5
votes
2answers
773 views

Why does ArcGIS Field Calculator expression unexpectedly return a binary value (0 or 1)?

I am running simple field calculator expressions and experiencing some of the silliest results I have ever seen. I am working on census data (living as a shape file) and trying to perform a simple [...
5
votes
1answer
4k views

Recording frequency of names in the attribute table?

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 ...
1
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2answers
147 views

“CountIf” or alternative function in ArcMap field calculator?

Within ArcMap 10.3 field calculator, I am looking to count the number of features in a column that match the current value, and output that count. Ideally, the output would look like this: Number &...
4
votes
3answers
603 views

Moving “last name” from last to first in Attribute Table of ArcGIS Desktop?

How do you get e.g. "John D. Doe" to "Doe, John D." in the AT using VB Scripting without going individually going through each line? I am using ArcGIS 9.3. I should note that not all the names are ...
4
votes
1answer
1k views

VB scripting in ArcGIS Field Calculator?

In my attribute tables field I am trying to get rid of the "&" in between names i.e. "John Adams & wife" and want it to say "John Adams and Wife" in all the attributes with "&". What is ...
0
votes
1answer
98 views

How calculate sequential values based on group field?

In field calculator i calculate sequential values in field [ORDER_ID] What need change in script to calculate sequential values based on group field [GROUP_ID]. I select values manually and use ...
1
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0answers
67 views

Replacing Null values with field calculator

My goal is to use the field calculator to replace null values. I am trying to replace nulls in the ToDate_Time with the FmDate_Time. When I run the code below the results window says that it worked ...
3
votes
1answer
47 views

Help with Rastercalculator - Filter areas with a certain height difference

I'm struggeling a little bit with the rastercalculator tool of QGIS. At the moment I am working with a DSM and a DTM. My aim is to filter all wind turbines out of the DSM and replace it with the ...
1
vote
3answers
276 views

Using Field Calculator to compare two fields in att table and returning if equal or not in ArcGIS for Desktop?

Using 10.2.2 I am attempting to compare two fields in an attribute table using the Field Calculator. I'd like to return a value of '0' if they are equal and a value of '1' if they are not equal. ...
2
votes
1answer
79 views

Reproducing GRASS GIS network analysis tutorial in QGIS Field Calculator

Im looking to reproduce the assigning of road speeds as denoted in a GRASS GIS tutorial (v.net.alloc tutorial), where the road speed is assigned by road type (i.e. 'interstate' = 75 mph etc.) to then ...
5
votes
1answer
5k views

Using VBA in ArcMap field calculator?

I am trying to use ArcMap's Field Calculator to populate values in a column based on a value in another column. So, in pseudo-code: if [field1] = 'Foo' set [field2] = 'Bar' endif Something like ...
2
votes
3answers
305 views

How to get around “The field is not nullable” error?

I have a shapefile of lines. I want the angle of every line calculated in a field. I am using the script below in arcmap, but when it encounters a line that is horizontal, it stops calculating any ...
1
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1answer
74 views

Copying some values from several columns to another column in attribute table? [closed]

I am trying to copy selected values from several columns to one single column in the attribute table. Specifically, where columns (Grid_code, grid_code1, grid_code2.... etc) have values of 4 and 10, ...
0
votes
1answer
81 views

Calculate percentages with field calculator in arcgis?

I am trying to calculate the percentage of each the area of each polygon in the selected area. I tried using ( math.fsum(!shape.area!) / !PolygonArea! )*100 and other codes but I cannot make it work. ...
1
vote
2answers
159 views

Update multiple fields/columns in QGIS

I need to update fields in attribute table of a vector using QGIS. I use field calculator for each field, but i have too many fields (and too many vectors also) and i need to program the task. The ...
0
votes
2answers
35 views

update cursor based on location

I'm working on a python script for ArcGIS 10.2/10.3. What I want is to automatically fill in a field of a point layer based on the location of that point in relation to a polygon layer. Say I have a ...
2
votes
1answer
783 views

Getting First and Last Point coordinates of Polyline with Field Calculator in ArcGIS Desktop?

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 ...
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0answers
11 views

How to calculate area percentage from polygons from one shapefile within another? [duplicate]

I'm working on a project where I have to create python code that takes land-use data and adds a percentage field for each land-use category in a Census Tract shapefile. I've been trying to work with ...
5
votes
5answers
4k views

ExecutING SQL script in ArcGIS field calculator?

I am trying to transfer over row data from a table to columns in a shapefile table. There is a common "SA" variable between the two (i.e. the study area number) but there is more than one land use ...
1
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1answer
25 views

Clearing Calculate Value before Model Run in ArcGIS ModelBuilder?

I am using ArcGIS 10.2 for Desktop. I have a model which contains several branches, which branch should run is based on the results of an earlier stage in the model. If the first stage of the model ...