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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37 views

How to fill the column in attribute table with same values?

I have about 19000 records, I added new column and I would like to fill it with string values (eg. brand)- same value for all rows. I'm not considering copy/paste. I know I could do it with exporting ...
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2answers
48 views

How to assign a unique ID to groups of items in the attribute table in ArcMap?

Using arcmap's field calculator I need to programatically loop through all of the entries in the field and for each name it gets its own unique id. So names that are the same would get the same ...
2
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1answer
35 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 ...
2
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2answers
148 views

Performing math in Python parser of ArcGIS field calculator?

I never used python but now I need a code to do this calculation: I'm doing this: math.atan(math.fabs( !Y2! - !Y1!)/math.fabs( !X2! - !X1!) )*(180/math.pi)
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1answer
33 views

ArcGIS Field Calculator nested elif is None not working

I am calculating a field based on two other fields in ArcMap 10.2 using python. My Pre-Logic Script Code is def myfunc(legend,Btype): if(legend == 'Apple'): return 'Banana' elif(legend == ...
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3answers
13k 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, ...
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1answer
62 views

Rewriting VB codeblock as Python for ArcGIS Field Calculator?

I am looking for assistance to rewrite my VB codeblock into Python. Im on Win7, Arc10.2 and Python 2.7 The code below works fine for me, I am simply looking to port it to Python so i can progress down ...
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24 views

Combine string and OBJECT ID

I would like to update the Map_Feature_ID field with a String " WP_" and then follow the "WP_" with the OBJECTID field. So I will end up with "WP_1", "WP_2" all the way to the end in the Map Feature ...
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3answers
534 views

Replacing Variable in VB-Expression-File (.cal) of ArcGIS Desktop?

I'm trying to modify a VB-Expression saved in a cal-file by ArcGIS Desktop 9.3: dim out if [D19830701]=-9999 then out= [D19830501] else out= [D19830701] end if ...
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1answer
80 views

Concatenate fields value excluding empty values

I need to concatenate the value of two fields excluding empty values, using Field calculator. The fields are: AREA_HI and AREA_LO I have tried using a Python script but ArcGIS returns an error ...
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1answer
68 views

if-else logic expression in field calculator

I want to calculate the value of a new field using an if-else condition with field calculator in modelbuilder. Want I want to do is as follows: if my new field is empty, then use the expression ...
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1answer
209 views

How to create sequential field based on sorted data? (or extract pop-up data?)

I downloaded a kmz field and converted it to a GDB fc on arcmap. However, the field I need to label the layer by is stored in the pop-up html field... It looks like this: <html ...
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1answer
63 views

if/then with VBScript in ArcGIS Field Calculator giving Error 000539: SyntaxError: invalid syntax?

What is wrong with this VBscript in the field calculator? ColumnC= if [ColumnB] > 0 then [ColumnC] = [ColumnA] / [ColumnB] endif Each time I receive this syntax error message: Error ...
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1answer
430 views

Field Calculator Runs In IDLE (2.6.5) but not ArcGIS 10 SP3

just wondering if anyone else is having issues with the field calculator in ArcGIS 10 SP3. In the following code I do a pretty simple field calculation with a variable (an array) as one of the ...
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2answers
420 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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1answer
44 views

Using Python parser of ArcGIS Field Calculator to populate values in one field based on those in another?

I am trying to populate a field with a sorting code that represents the value of another field. Example: EXPCODE|SORT| S4DNN2 |3.5 H2BNN2 5.0 EXPCODE is a field with a value like "S4DNN2." SORT ...
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1answer
34 views

Coordinates for specific points calculated in QGIS Field Calculator?

I have got a layer in QGIS that is comprised of connected points which define regions of a country, thus the attribute table consists of 38 regions while the number of nodes in this layer is about ...
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1answer
37 views

Getting and using XY centroids in ArcGIS Field Calculator using Python Code Block

I am writing a script to obtain Grid reference but cannot fathom how to get XY centroids without creating new fields (all examples I have found are based on writing XY centroids to field). Here's ...
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1answer
42 views

Using defined function code block with Python in ArcGIS

I am running a Field Calculation within a Python script in ArcGIS. Within this Field Calculation I am calling a defined function within a code block. Here is the dialogue that I ran and works: ...
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0answers
12 views

How to get 1st and 2d vertical derivativ from gravitational survey? [closed]

I have a bouguer anomaly map and i want to do a vertical derivativ on it so i did 2d fft on gravity data then i used this equation : A(u,v)=A(u,v)*(SQRT(u^2+v^2)/n)^n after ...
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2answers
77 views

How to add multiple python expressions in field calculator

How would I add multiple python expressions in the ArcMap Field Calculator if possible? I tried separating each expression on a new line and also separating with a semi-colon but neither worked. ...
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2answers
49 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 ...
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1answer
169 views

Calculating a Unique ID on a Subgroup of Polygons

I would like to assign a unique ID to polygons in a dataset. The catch to my issue is that I would like polygons that fall within a polygon to have the same unique ID. My example is related to ...
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2answers
47 views

in attribute table [closed]

Rows consist of letters and numbers that had 6 strings expression. I want to group these rows according to at least 3 strings be similar. How can I do?
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29 views

Network Anlayst hierarchy evaluator [closed]

Working with ArcGIS (v10.2.2) Network Analyst and reformating the road network with a hierarchy evaluator and receive the following error message: The field evaluator result statement has multiple ...
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4answers
72 views

How to remove period, comma, symbols using field calculator?

I want to delete . , # in attribute table using field calculator (VB Script or Python). How can I remove these using this example address: N. First St., Unit #1 (I don't need city or state name) I ...
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1answer
146 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 ...
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3answers
2k views

ArcGis Python Script, Calculate Field

Sorry for my English. I am trying to write a Python Script for ArcGis 10.2. #import system modules import arcpy import math from arcpy import env #Set environment options ...
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2answers
268 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 ...
0
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1answer
75 views

Problem with addιtion abstraction in Field Calculator

I want a bit analytical respond for the mistakes I have done in my code cause I am new to programming. I am using ArcGis 10.2. and I must process a field with distances in an attribute table I have. ...
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2answers
3k views

using mod() with IF THEN field calculation

I am trying to use the field calculator to assign a "odd" or "even" value to a field of small integers. I usually do this with by selecting where: MOD([field],2) = 0 and then just calculating it ...
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42 views

Iterate through all fields in attribute table and multiply by field

I have a table with a whole bunch of census variables (race, age, education, etc). I want to multiply all of these fields by a factor that I calculated. For example: Field1 has values of 10,20,30,40 ...
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1answer
112 views

How to remove comma from combined fields which should be null?

I have Drivers License as one field and State as the other and there are to be combined and formatted as Drivers License, State. How do I handle records that do not have either a Drivers License or ...
2
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1answer
29 views

How to change GK-coordinates to UTM with the field calculator in QGIS?

i have a qgis project in ETRS89 (UTM) with some vectorshapes. i already transformes them from GK into UTM. but now the attribute table still show me the GK-coordinates. HOW can i change it? with the ...
4
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1answer
195 views

Converting 12-hour time to 24-hour time using Field Calculator

Does anyone know how to convert string time formats in ArcMap v10.2 from 12-hour to 24-hour using a simple query in the Field Calculator? i.e. NO Python, NO editing in Excel, NO changing my Windows PC ...
2
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3answers
101 views

How do I normalize the values in a single Field (from a table) in ArcGIS?

First of all, this is my first post, and I would like to appreciate all the useful information I have found so far on this site. Second of all, I have encountered a problem, in Field Calculator. ...
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1answer
51 views

Attribute table not updating after QGIS field calculator used? [closed]

Using QGIS 2.8.1 i am trying to update an attribute table using the field calculator. its a vector layer of vegetation communities. i am trying to update the area fields in the table. The output ...
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2answers
461 views

area values determined with field calculator become null when saving

using field calculator in Qgis 1.8.0 to get the area, it shows just right at first but when I save it, the values become Null. help please
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1answer
40 views

Concatenating fields while also replacing values within certain stings [closed]

I am trying to use python to concatenate multiple fields in a polygon layer. Specifically, I am attempting to combine the values of four fields into one: EXPCODE = !MATRIX! & !PLANT! & !PCT! ...
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1answer
334 views

Join and Calculate vb.net

Im trying to join an excel table to a shapefile and then calculating those fields using vb.net. The code I have written has no errors, but won't work when I try it in ArcGIS 10.1 and I'm out of ideas. ...
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1answer
204 views

Slow performance with Add Join and Calculate Field?

I have a point layer and a table with approximately 100 fields. I need to join the table to the point layer based on a key field and create a new shapefile / feature class. This script has been ...
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1answer
401 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 ...
2
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2answers
54 views

How to convert negative field values to positive?

I have an xyz file that I want to convert negative field values in the z column to positive values. How do I do this with field calculator?
2
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3answers
63 views

How do I use the field-calculator in QGIS to return the name of a country from a different shapefile?

I have a shapefile that consists of a list of archaeological sites with the x and y coordinates. I have an Natural Earth shapefile for the countries of world. I was wondering how I go about ...
0
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1answer
24 views

ArcGIS do calcuation on multiple input fields of attribute table and the number of input fields is changing

I have attribute table with headers: ID(bgrp), F1 (F2011_46), F2 (F2011_48), ...Fn I want to do math calculations on the fields from F1 to Fn. For example, count the total number of non-zero Fn ...
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9k views

How do you test for a NULL string field in the Field Calculator with Python?

I am trying to perform an operation on a string field with a condition that it contains data. Referencing None with Python does not appear to work when the field is nullable and contains <Null> ...
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18 views

Incorrect Acreage QGIS 2.6.0

I have six polygons, all of (fairly) similar size. The first one is 8 acres, the others are obviously wrong with 120,000 acres, and 106,000 acres and so on. I am calculating with the field calculator, ...
2
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1answer
25 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 ...
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3answers
879 views

Why do area calculations return negative values?

I have created a shapefile with some polygons and am now trying to calculate the area of these polygons. The original CRS was WGS84, I have reprojected it to WGS 84 / World Mercator so unit is metres. ...
0
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1answer
24 views

Raster Calculator or Local-Combine tool? (in ArcPy)

i have 3 classified rasters and i wanted to use the following query from r. calculator: (rclslope>=45) & (rclmosaic>=2000) & (rclfocal>15) to arc.py how can i write it? Is it ...