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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Calculating values of field based on two others using Field Calculator in ArcGIS Desktop?

I need to combine two fields in an attribute table. I want to do this using the field calculator. What is the proper script to write to combine a field called "name" and "type", so that it produces ...
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795 views

Automatically assign numbers to point file in various order in QGIS

I know how to automatically assign numbers to a new point files using the $rownum function in the field calculator. However it does it from the top-left over and down like reading a book. I could ...
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46 views

Add and Calculate Field in Table with ArcPy?

I have written the following script to iterate it as a tool for all my tables with ModelBuilder, but i have a problem wth my codeblock. I want to add a field FID to all my tables and to add the values ...
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How to update a bulk selection of fields using field calculator in QGIS 2.8.1

I have an attribute table showing vegetation communities. The table has three columns ("ID", "Veg Comm" and "Area_ha". Instead of having to copy and paste text after each polygon created into each ...
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38 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 ...
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57 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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72 views

Calculate field based on other two added fields in ArcGIS Model Builder

I have a model in model builder where I add 2 fields, "field 1" and "field 2". For each field I calculate their values using the calculate field tools. Afterwards I add a third called "Field 3" of ...
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146 views

Cannot convert string to int using ArcPy Calculate Field

When I load a csv file to join with ArcPy, it converts all string fields that are numeric to integers. Therefore, I have to add another field within the feature class that I'm using for joining that ...
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61 views

VB Script field calculator - error with conditional statements

I have limited VB Script experience, but have been working on the script below and keep getting errors, the most common being "expected identifier". Can someone tell me what I'm missing here? Dim ...
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85 views

How to perform If Statement in Field Calculator of ArcGIS for Desktop? (Python or VB)

I've one field "MAXSPEED". I want a Field Calculation that will calculate an additional field ("noise"): If MAXSPEED > 40 then the term: (73.5 + Log ( 25 ) * ( [MAXSPEED] / 50)) should be used to ...
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47 views

how multiply a ranges of values for other value on python

I need multiply ranges>1.5 and <=4.5 * 9, but I am new in this type of language. please help me. def CalcD(Level_water) if Level>1.5 and <=4,5 * 9
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What's wrong with this VB Script code for the field calculator in ArcGIS 10?

I am trying to use one field's contents ([Condition]) as a condition for populating another field ([Intact]). I try to run the following code in the Field Calculator, but it never works (and is not ...
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145 views

Calculate value from an equation using Field Calculator Python/VB Script

I wanted to calculate a result value from 3 fields using an equation. VBScript or Python codes are also accepted..:-) the equation is RESULT= [(R^2/3)(S^1/2)]/n..
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266 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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92 views

Calculating Field B from Field A, except where Field B has existing value, using ArcGIS Desktop 9.3?

Im trying to calculate Field B from Field A except where Field B has existing value in ArcGIS Desktop 9.3. (I suspect its straight forward but I have 'searched' and havent cracked it yet) Any ...
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217 views

Debugging CalculateField_management ERROR 000623: Invalid value type for parameter field?

I am trying to select records in my table that have certain words in the "Name" field and then code them as 0 (not pharmacy) or 1 (pharmacy) This is just a test searching for two words to select ...
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119 views

How to include a quotation mark in a text field from field calculator

I'm trying to attribute pipe size and need to include a quotation mark in a text field. How do I include that in the field calculator. "4"" doesn't work.
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81 views

Python in ArcGIS, CalculateField_management, updating with single value

I have a float field which I want to simply update all values with 1. I can easily do this within the field calculator but I have started using python today, what is the syntax to simply update a ...
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147 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 ...
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94 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 ...
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2answers
1k 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 ...
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292 views

How to concatenate XY values in attribute table without messing up the numbers in ArcGIS 10.1?

Here's the procedure I use and the resulting problem I'm having. First I use the Add XY coordinates tool to add POINT_X and POINT_Y fields to the attribute table of a point layer. I then add a new ...
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273 views

Stuck updating one field based on the condition of another using Acrpy or Field Calculator

I have a shapefile with 5,000 city points. I need to populate a new field, "cls_pop", based on each cities population, so that cities with a population > 2,000,000 will have "cls_pop" = 1, cites with ...
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473 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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Concatenate Fields into One Field in QGIS

I have seen some posts on this, but only for ArcMap. I am looking to take a range of values from two fields and concatenate them into one field to make a unique value. For example: XMAX YMAX ...
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462 views

FieldPyculator Plugin - How to Classify Fields?

Could someone tell me how to classify/populate fields with QGIS FieldPyculator Plugin? In the Attribute Table, I have a field named POPULACAO with population data: I want to apply a weight to ...
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259 views

Small issue with field calculator

What am I doing wrong in this field calculator logic? Pre-logic def re_score(elev_t,f2, contour): f2=contour if elev_t.endswith('.5'): f2 = "Midi" return f2 Expression for field "Contourtyp" ...
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344 views

How to tranform a column field into a list using Field Calculator

I'm trying to make a simple field calculation with ArcGIS 9.3: New field = Old field - Old field(first value) which in Calculate Field with python code should be Expression: !Old field! - first ...
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51 views

Area is calculating wrong using $area in field calculator (QGIS 2.8.1-Wien)

There is a similar question posted, but the solution to it seems to be that polygons were multipart: Wrong $area from field calculator (QGIS) In my case, all polygons are singlepart. I have several ...
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50 views

Calculate area intersected areas, problem

(I'm working in QuantamGIS) I intersected two layers creating a new layer. Within the attibute table of this new intersect layer i would like to calculate the new areas. However, it just doesn't ...
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59 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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66 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 ...
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46 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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44 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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47 views

How can I allocate a $rownum in reverse order in QGIS?

How can I allocate the $rownum value in reverse order in QGIS? I have a created a grid layer to use in an atlas and the ID allocated is from top left to bottom right - which is what I want if I want ...
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161 views

Using Python in the field calculator - if/else over multiple fields

I'm trying to work out how to populate a field depending on the lowest score across 6 other fields. I've read several other questions relating to if/else statements but I'm only just starting to learn ...
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98 views

Setting field equal to raster Name ID for batch process in ArcPy

I am wanting to set an existing field called RasterID to the name of the raster for which the attribute table belongs to, but for a batch of rasters. Is there a way to do this with my current code ...
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41 views

Multiply whole column with the field calculator in QGIS

I have a layer with the field size. I did some mistake with the value and now I need the values multiplied by 16. But instead of going through 500 lines and recalculating them I would like QGIS to do ...
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49 views

How to use field calculator in QGIS to calculate new coordinates, and use that new columm to geolocate a layer's points

In a separate question, at How to shift a CRS by an observed offset, I asked about shifting a CRS to align the problems aligning data points with a satellite image obtained from OpenLayers. (They ...
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94 views

ERROR 000989 Issue with Python Script and Field Calculating distance between two long lat points

very new to scripting and I have been struggling with my script for a while. I'm not sure why it doesn't work in field calculator. I am trying to calculate a list of distance between two long lat ...
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47 views

What is the expression for getting a subset of characters in QGIS Field Calculator?

I have a column of 10 character names e.g. L3NAM1988K. How can I delete the first 5 characters and the last 1 character using an expression in the QGis Field Calculator?
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169 views

Using if else statement in Python Parser of Field Calculator in ArcGIS for Desktop?

I need help in writing the python script in the field calculator. I have three fields namely: CODE COMPLEX Map1 Map1 is an empty field that I want to populate. I have a number of conditions to cater ...
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155 views

Field Calculator - How to evaluate and sum multiple fields?

I'll do my best to describe the problem - my main issue isn't so much the python code but rather the logic I'm using. The file I'm working on is a polygon shapefile with forest attribute data. In the ...
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153 views

Remove Leading Zeros with QGIS Field Calculator

I'd like to take this attribute value: "MAP_PAR_ID": "0160011000", and populate a new field with "16-11". This works: concat(substr("MAP_PAR_ID",0,3), '-', substr("MAP_PAR_ID",5,3)) but i need to ...
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Syntax to add attributes in a line in the Expression String Builder

I have several columns with certain values, here's an example: | Apple | Banana| Orange | Pear | Expected result | 1 | 1 | 1 | 1 | red | 1 | 2 | 2 | 1 ...
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Sum a field in buffer intersection

I have looked and do not see this answered in any other discussions. Purpose: Site suitability analysis for brewers spent grain processing facility Method: Locate intersecting buffers with greatest ...
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How to use Fields in the Field Calculator? [duplicate]

I'm using the Field Calculator in ArcMap and I need to create a unique ID for every storm drain in my county. An ID Should look something like this: 16-I-003 The first number is the municipal number ...
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136 views

Using the Rule-based style to calculate each grid cell from overlaps

I am using the Rule-based styling properties (QGIS 2.2) to determine the colour of grid cells for a merged shapefile. Each grid cell defined by its ID may be overlapped by several layers as defined by ...
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72 views

Arcgis 10 assign values to field based on values in other field [duplicate]

I have a table with two fields A and B, and i want fill field B with "some values" from field A: FieldA: 123456_CC; 123_D; 1234567_AB; 123456768_F I just need the "text" that is associated with the ...
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77 views

Create and immediately update field using Field Calculator

You can create fields and once created, populate them with data using the Field Calculator. But can you do both at the same time using an expression? Or must you do it in 2 steps?