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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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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86 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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114 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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80 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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134 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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90 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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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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264 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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264 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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2k 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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465 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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1k views

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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460 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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252 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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343 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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41 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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48 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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55 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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43 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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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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34 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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55 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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156 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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84 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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37 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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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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46 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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144 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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145 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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139 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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222 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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66 views

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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67 views

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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124 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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73 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?
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30 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?
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163 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 ...
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460 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 ...
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284 views

Cursor Update Python Script for Multiplying Several Fields against a Ratio (Real) in ArcGis

Disclaimer: Python Neophyte, Uber-reliant on GUI, working to wean... I have a Python script for replacing multiple Field values with another table value that was graciously provided by the inimitable ...
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241 views

Using a different projection to calculate areas using the Field Calculator

I have a dataset that is in a WGS84_UTM projected coordinate system, can I force the Field Calculator to use another coordinate system when I use it to calculate areas using pythons ...
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323 views

Convert a number in attribute table to binary

I would like to convert whole integers from decimal to binary in ArcGIS using the field calculator. I am looking for the equivalent of DEC2BIN excel command. All values are 255 or below so 8 bit is ...
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317 views

Stop rounding values in Qgis attribute table

I am calculating the areas of my polygons in Qgis using $area and everything works fine until I click on "save". All my values are rounded to an integer. I tired setting the output field type to ...
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73 views

How to move a value from field1 to field2 using Field Calculator?

Hi I would like to move value in field1 to field2. Purpose is to after that delete the column 'field1' to get a better column naming standard /Jan
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649 views

How do you calculate a column value based on the value of another column?

I am trying to select data based on whether it starts with certain characters and then update a field. For example if [Asbuilt] starts with "WL" then do something. Here are the two methods I have ...
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3k views

Use Round in ArcMap 10.x Field Calculator on field with both numeric and NULL values

With older versions of ArcMap (9.3, 9.2, etc) I was always able to round numbers down to 2 decimal places using field calculator even if that field had both numeric values and a bunch of NULL values. ...
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ArcGIS field calculator: VBScript get data from previous row

When using the field calculator, how do I get data from the previous row in VBScript? In Python I'd do something like this: for index, row in enumerate(rows,start=1): row[index-1] += 5 I'm ...
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22 views

Using “calculate field” in python script fails to display Arabic characters correctly

Using “calculate field” in python script fails to display Arabic characters correctly. I have exported the modelbuilder to python script, but unfortunately the Arabic characters cannot by displayed ...
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38 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 ...