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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If/then python for classifying existing field values to a new field

I'd like to have a tool or quick python script to classify an existing number field to a new text field. For example I have a roads layer that has a type identifier as a coded number and I would like ...
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40 views

extract substring after first number

Suppose I have a field titled NAME1. Examples of what is in the field appear like this: Fox Lake 1 WABASCA 166 TSU TUE 196G YELLOW QUILL I.R. 90-8 POUNDMAKER INDIAN RESERVE NO. 114-17 CROSS LAKE ...
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45 views

Update all cells in column to match value of first row?

I have a point layer; the attribute table includes x and y coordinates of original centroids associated with the points (the points were generated from the perimeters of circle features and still ...
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2answers
59 views

Error msg “Name is not defined” when trying to populate a field with the shape file name

I am trying to populate a field with corresponding file name. For example, if the file name is Route1.shp then the field value will be Route1 as well. However my code is not working. Can you please ...
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41 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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77 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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85 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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95 views

new layer from calculations with fields of other layers in QGIS

I've two layers, both with the same fields: A, V, where A is the shape's area and V a value given by me. I want a new layer with shape created by the intersection of the other layers' shapes and a ...
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30 views

How to update the value of a field dependant upon the the fields ID in QGIS Field Calculator

I am looking to create links to website pages and to automate the procedure a bit more I would like to have a standard link followed by the ID of each field. For example, I would like the standard ...
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90 views

Use field calculator to reclassify values from three different fields to populate a new field AND determine overlap with different raster

I want to reclassify values of 3 different fields AND determine if one of those fields is located inside a different polygon to populate the values of my new field. Everything is raster. I created a ...
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219 views

Calculate field in model builder using file name

I have browsed answers to similar questions but I still cant figure it out. I have created a new field called "namemonyr" in all of 646 shapefiles. I now want to populate that field using ...
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92 views

How to calculate distances in QGIS field calculator?

So I'm using qgis 2.6.0 and I have a csv (converted into a .shp) with two geometry columns, I want to create a new column with the distance between the two geometry: shot.lat shot.lon haul.lat ...
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360 views

How to calculate unique IDs starting from highest current ID

I have been using a python script in field calculator in ArcGIS 10.2 to add unique IDs automatically, however there are two things I would like to improve this process: Each ID also has letters at ...
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114 views

If/then Field Calculator

I have two fields in my model, the first is a spatial join return for the township, the second is a spatical join to a city. If there is not city, then the field is left blank. The column that has ...
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85 views

Use Field Calculator to change “Status” field in Annotations

I am trying to turn off a lot of annotations at once by using Field Calculator to set status to Unplaced. Just typing "Unplaced" into the expression, I get this error: The calculated value is ...
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244 views

ArcMap 10.1 Crashing when using field calculator

I keep getting a serious error message when I try to use the field calculator. I've joined a .csv to my SDE feature class and am trying to set one of the columns equal to one of the columns from the ...
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174 views

Updating a feature class

I am working on ArcGIS 10.2.1. I have a feature class containing more than 4000 records and a table having approximately 1000 records. Both feature class and table have some common fields however, ...
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188 views

Conditional Calculate Field Many to One

Anyone have experience calculating a field based on a many to one scenario? I have a feature class in a geodatabase with a field of unique names. Feature Class Table (let's call this ...
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367 views

Autoincrementing Python Script is over writing all fields versus just fields that are null

Using ArcMap and the Field Calculator I have a python script that should autoincrement the FacilityID field if it is null. It works the first time through but the second run causes it to overwrite ...
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271 views

Replacing attribute table entries using Python script

I am using ArcMap 10 from ArcGIS 10.2.1 package. I got an attribute table, with few collumns. I need to replace some column "String_A" entries with newer "String_B" entries, in the same row. In both ...
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2k views

Getting ValueError: max() arg is an empty sequence on a Python Script in the Field Calculator in ArcMap

I have a script that populates a FacilityID Field on a Attribute table in the Field Calculator but when I run the script below I am getting a error. EDIT: Python Script: def autoInc(): import ...
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61 views

Field Calculator extract three last digits from another field

How everyone! I have two fields the on is the cadastral number which is for example 051020213001 and I am trying to fill the other field (label) with the last 3 digits from the cadastral number, in ...
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284 views

Auto increment a new column using Model Builder Field Calculator in QGIS?

I am making a model which requires creating a grid and clipping various layers to it. Using the Create grid function does not provide an ID column, instead it creates 2 columns: "longitude" and ...
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199 views

Error when dividing a field with a number

Using arcpy CalculateField_management i want to divide a field with a spacific number: arcpy.CalculateField_management(EZG_shp, "IDX_AT_PK", "(!EURO_SUM!/!Anz_Pers!)/1668,4","PYTHON") This works in ...
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2answers
52 views

How can I populate a field of the polylines to indicate if they intersect?

I have two feature classes, one ploylines, one a buffer. How can I populate a field of the polylines to indicate if they intersect?
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479 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 ...
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145 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: ...
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235 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 ...
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222 views

Help with field calculator in Python script

I am getting a syntax error in my script but I know from testing it in ArcMap attribute table, the syntax is fine. Anyone have any idea why this code doesn't work? I see that a search cursor has been ...
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117 views

How to perform intersect operations in the Field Calculator in QGIS?

How to use the Intersect function? How would I specify to REPLACE layer1.field1 with layer2.field2 WHEN layer1.geometry INTERSECTS layer2.geometry Is that feasible in QGIS?
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272 views

How to correctly use LIKE in the code block of a Reclass expression in ModelBuilder Calculate Field

I have a Reclass expression that works when i am search for single instance of a data field. I also wish the Reclass to work with a SQL type LIKE selection with Wildcards. e.g. I need to reclassify ...
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359 views

Python Field Calc for Document Hyperlink

I am trying to create a script that will hyperlink to a .tiff or .pdf. These files are stored in one folder on a shared server. I want the script to look in a field: 'PLAT_IMAGE', which has the plat ...
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456 views

remove whitespace Python code results in odd character - Field Calculator

I need to remove whitespace from the end of a string in a field in ArcMap. I tried first the VBA function RTrim, but whitespace still remained. I thought maybe the whitespaces were tabs, so I tried ...
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221 views

Comparing field values to update new field using ArcGIS for Desktop?

I am currently doing an analysis in ArcMap 10 using python. I have two shape layers, one is a point layer and the other one is a line layer. The point layer have attributes for point's unique ID, as ...
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2k views

Using File Geodatabase with Null values in Field Calculator of ArcGIS Desktop 10.0?

I want to use the field calculator to get the sum of a couple of columns. The problem is that some of them has Null Values. I am not able to find a solution. I tried this Python functions: stack( ...
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113 views

How to reach a field value of a record in field calculator in ArcGIS 10.1

I have two fields showing number of people in two age groups "young" and "old". these people also live in a cell (point) whose distance to a specific facility is calculated. then I categorized these ...
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568 views

How to calculate field as cursor name?

First time dealing with cursor. I have lines intersecting polygons, I want to get a table with all attributes of the lines, add a field and calculate the field as the name of the polygon. I was able ...
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95 views

How to import text only out of a string field to a new field

I want to import data out of a string field in my shapefile to a new field for labeling. The string field contains river names and codes and I just want to display the text i.e river names
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435 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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2k views

Do QGIS Field Calculator xat(n) and yat(n) functions work in version 1.7.x?

I'm trying to use the xat(n) and yat(n) in the Field Calculator but can't get them to work. Does anybody have an example how to use them? I need the start and end coordinates for line segments, does ...
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13 views

How to add the values of a common field to a field during union

If I have say 3 overlay features; A,B,C each has a field called FIELD_ID If I do a union, I will get 3 new fields in the output: FIELD_ID_1, FIELD_ID_2, FIELD_ID_3 But how do I get just one ...
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33 views

Using ModelBuilder or Python parser of Field Calculator to check values between two datasets?

I have a *.dbf that I need to check values against for a shapefile. I need to report whether the values match the dbf in the shapefile and, if not, what the value should have been (in two new ...
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46 views

How do I Calculate Grouped Percentiles or Batch percentiles in ArcMap?

My question is similar to this one which was answered successfully: Calculating Percentiles in ArcMap? My addition is how do I batch this solution for multiple files or apply a group-by feature to ...
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42 views

If then statement in model builder

I have a model that adds several fields, two which are manual inputs (County Name and User). I am manipulating several parcel layers (approx 90 counties). In my model, one field takes the state and ...
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25 views

Forcing area calculation into miles in QGIS (without changing the PCS) [duplicate]

I'm working on an assignment that requires me to create an area column in miles without changing the projected coordinate system. ArcGIS has a tool that can do this ('Calculate Geometry')-- does QGIS ...
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39 views

Using Advanced Python Calculator in QGIS Modeler

I'm trying to create a column with integer values based on a small function that basically uses conditional statements. In short, a reclassification. My attempt below: def getValue(Etat): if Etat ...
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73 views

How to use QGIS field calculator between different points of same layer?

I'm in a course learning about GIS systems, and we have recently recorded a gps track. I've exported this track as .gpx and imported the points into QGIS. Each point has a timestamp. One of the ...
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49 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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36 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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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, ...