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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70 views

Adding Rasters with multiple Field Values using Map Algebra in ArcGIS for Desktop? [duplicate]

Embarrassed that I haven't looked at this for some time (can't quite get the syntax down). (ArcGIS 10.2, Win7x64). Within Map Algebra (Raster Calculator) Trying to add the cell values of 3 rasters, ...
3
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1answer
43 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 ...
2
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4answers
95 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 ...
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1answer
78 views

Spatial join multiple attributes from smaller polygons to the bigger one

I'm trying to join (to the rectangle) values from multiple polygons intersecting for this rectangle. I've tried to use some Reference functions in Field Calculator like geomintersects() but it joins ...
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1answer
209 views

How to convert text to proper case using the field calculator?

I am working on a set of data that has over 40,000 records on ArcGIS and I want to use a Proper Case for several fields/columns on the table. Is there a Python or Java Script that can help me automate ...
2
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3answers
145 views

How to calculate Statistics of an attribute field to use it in another calculation

I want the statistics of an attribute field to use in another calculation, i can view the statistics using the field properties menu I want these to normalised the data of field 'Ia' using the ...
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1answer
29 views

Summarize multiple columns in field calculator [closed]

I am performing the Huff model with 10.000+ facilities and dwellings. As a result, each facility has a value between 0 and 1 that determines the probability a consumer patronages a facility from a ...
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1answer
69 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, ...
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10 views

Replacing null values in cell with integer using Python parser of ArcGIS Calculate Field tool? [duplicate]

In one field I have certain cells that are filled with null values. I am trying to change all those null values to 0 or say even as random as 100. I tried with the Calculate Field tool the following ...
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1answer
50 views

Capitalizing The First Letter Of Each Word In Attribute Field QGIS

I have tried capitalizing the first letter of each string in my field/column called "COMMUNITY" by referencing this post: Capitalizing The First Letter Of Each Word In Attribute Field Particularly: ...
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1answer
47 views

How to convert a “yyyy/mm” field to “yyyy/mm/dd”?

I am trying to edit an existing date field of the form "yyyy/mm" to a format that the TimeManager Plugin for QGIS can handle - I guess "yyyy/mm/dd" will do it. I've got as far as opening the ...
2
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1answer
72 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 ...
3
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2answers
127 views

Arcmap field calculator python script returns no data

I am running ArcMap 10.2 I have 4 fields with which I am working. many have duplicate entries. in order to find the single correct entry from all the duplicates I am trying to calculate out the ...
2
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2answers
157 views

QGIS 2.12 attribute table update question

I'm trying to fill in a whole lot of cells in the same column of an attribute table all at once using the field calculator. Am I on the right track with the following expression? "Author" || ...
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1answer
358 views

How to copy same values to another field in attribute table in QGIS using field calculator?

I am trying to copy values from Parsel_ID to Parsel_NO using an equation ( look at pictures) in field calculator but it is not working. What is the problem and how can I success this task??enter image ...
4
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3answers
223 views

Using IF operator with Python parser of ArcGIS Field Calculator?

I want to assign numbers to a certain types of building and I need to use field calculator. I tried many different versions of this and I still cant find whats wrong. Could you tell me where do I ...
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1answer
187 views

Use Get Field Value tool to calculate field?

I am running a summary statistic on a clip to get acre counts by area type. I want to then add a second field that has the acre count from the total area. A third field be added so that it shows as ...
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0answers
39 views

Using timestamp field to auto complete source field in QGIS

I am trying to use my timestamp field to autocomplete my source field in QGIS using the field calculator. I want my source field to be completed with a saved string e.g "Sam_Sam". I want my source ...
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1answer
146 views

Filling fields with conditional clauses

I have four fields in my shapefile. I would like to fill only one of them (cell of attribute table) and automatically after to write one cell the others one will be filled by conditional clause. I ...
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1answer
80 views

Python if/then Statement in Field Calculator to return 0 or 1 based on numbers divisible by 28?

I don't use python all the time. In a point feature class, I'm trying to populate an ID field with 1's and 0's based on whether the FID is divisible by 28. I've started the following code but ...
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2answers
84 views

Understanding if-else statements in ArcGIS field calculator when coded value domain used?

I am attempting to set a newly created field based on the strings in another field 'TNMFRC'. I am pretty sure that I have the code write, and yet everything is set to a value of '6'. Here's my code: ...
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1answer
170 views

Python script for if/elif condition in field calculator [duplicate]

I need some help in calculating the last column (OD_pairs.Ai_) based on the condition; if travel_cost has a value below 10, OD-pairs.Ai_ takes the value of the first column(Aij_OjFCij..) if ...
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1answer
51 views

Help with else/if else in arcMap? [closed]

I'm attempting to create quick code that simply assigns a gps coordinate to a certain station on the map. Here's my current code Pre-logic script code: def update_nones(lat,bay_statio): if ...
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1answer
64 views

Getting different values for area field calculations using ArcGIS Desktop?

We have self developed application based on ArcGIS 9.3.1 SP2. Our agents use that application to edit parcels. The parcel layer has a field SHAPE_AREA that is calculated by ArcGIS. Our application ...
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2answers
100 views

Using ArcGIS Desktop field calculator (python) to parse date

I'm trying to parse a datetime field using python (but have never used python for it before). I have a field that contains a valid date, but not a valid time... and other fields that have valid hour ...
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1answer
39 views

ArcGIS 10.2: VB to Python

I have the following VB code to produce a percentage in a field calculator. " [FIELD_1] / [Total]*100 " It works in VB. I've tried the following without luck. !FIELD_1! / !Total! * 100 Can anyone ...
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3answers
188 views

Unable to replace Null values using Python parser of ArcGIS 10.0 Field Calculator?

I'm using the following python code to replace Null values by 0, using field calculator: def nulls(p1): if p1 is None: return 0 else: return p1 But nothing happens, Null values stay. I'm ...
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0answers
68 views

ArcGIS 10.0 Python script won't recognize null [duplicate]

Has anybody ran into in issue where Python field calculations and/or scripts won't properly query Null (None) values? The calculation I'm working on is a little more complex, but even the simple ...
2
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1answer
46 views

Using Arcmap to update a field based on data from another fields

I'm trying to update latitude and longitude data per individual station for a lab I'm working for. Here's some code I have that's supposed to assign any all bay stations of a certain name the ...
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1answer
56 views

Using python to do a interpolation on field calculator [duplicate]

I need to increment a row in attribute table: def func (w,v,pot): return pot + ((pot+1 - pot)/(v+1 - v))*(w-v) The "+1" is not the addition of number one to the variable, is the intention to ...
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1answer
38 views

A script to populate a numeric field in Arcgis based on some content of a string field?

I have field in an attribute table populated with expressions like "6S2Olch1E", "10S1B", "9B3S2Olch" and so on. I need to make a numeric filed populated with only numbers associeted with letter S from ...
2
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1answer
53 views

Calculate field using data from excel table

I need to interpolate data that I have in a excel file using data from an attribute table of a point feature. I want to create a new field on the attribute table with the result of that interpolation. ...
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1answer
201 views

Writing expression syntax for Calculate Field in ArcPy?

I'm stuck on my CalculateField function with how to correctly type the syntax. I'm not particularly tied to the variables I assigned up front. The issue is syntax for the expression. I am ...
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2answers
103 views

Removing extra string from text column in Attribute Table to make numeric column from number part using ArcGIS Field Calculator?

I received a shapefile about invasive species. I am using ArcGIS 10.2 for desktop. In Attribute Table, there is column called "Infested_Area" and its got number mix with text, for instance "9100 sq ...
2
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1answer
116 views

Calculating percentage using QGIS Field Calculator?

I have a shapefile containing counties and their respective population for a given area. I woould like to use the Field Calculator to create a new field that contained the % of the total population in ...
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Calculating Grid square page names using loops, counters/cursors [duplicate]

I've created a large grid of 1 sq-mile cells to use for QC projects at my job. I've given each row a letter ID, and each column a number ID. So the grid starts with A01, goes to A02, etc. Next row ...
3
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1answer
74 views

QGIS field calculator returning results in different units?

I am trying to use QGIS to get the perimeter, area, bounds width, and bounds height of US congressional districts, using the US Census TIGER shapefile. I loaded the shapefile into QGIS, set my CRS to ...
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1answer
246 views

Passing two variables into codeblock of Calculate Field tool of ArcGIS Desktop?

I have a script tool that truncates each word in field to 3 characters and outputs the result in a new field: "THIS IS AN EXAMPLE STRING" becomes "THI IS AN EXA STR" import arcpy ...
2
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1answer
124 views

Create list of [X, Y] coordinates within field calculator

Lately i've been working on a script that must calculate a value in ArcGIS field calculator based on all vertex coordinates of a polyline. But i am struggling to create a list of a polylines ...
0
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1answer
59 views

calculate specific rows and populate their result in another field

I'm working on ArcGIS 10 desktop version. I have a file with one entity entered multiple times (rows) and each time that has been given a new value against it. I want to sum the values against this ...
0
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1answer
37 views

Updating Values in FIelds of ArcGIS editing only portion?

I have total 96 records which are having duplicate values like 999999. What i want is to convert these values into unique ones like 999901,999902,999903 and so on, through the 96 records. I want ...
2
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1answer
127 views

Convert Field Expression to ArcGIS Python Script Tool

I've created the following field calculation that I'd like to convert to a python script tool: def blocklow(a, b, c, d): mylist = [a, b, c, d] # create list from input range variables if mylist ...
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52 views

Concatenation of fields with if or when circumstances

I have a field named PROJECT_DESCRIPTION that concatenates the STREET_NAME, FROM and TO fields. Sometimes the FROM or TO fields are only address ranges. In my PROJECT_DESCRIPTION field I would like to ...
2
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1answer
77 views

Selecting numbers within the slash (/) using ArcMap Field Calculator?

I have date data that I'm separating into three separate fields (all fields are string type, including the input field) by day, month, and year. Unfortunately, the date field is raw data and isn't ...
0
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2answers
149 views

Find minimum in a column of attribute table using python on Field Calculator

I have a column X in attribute table where the values are repeated in some lines. What I need is to make a condition that says: when the values in column X are the same, find the minimum of column Y ...
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2answers
75 views

Extracting a Feature Class' Name, and Adding It to a Field

I'm building a bike network dataset based on an existing street network. Each bike lane/route/path has a unique ID number (assigned by our engineering deparment) that must be included in a separate ID ...
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1answer
60 views

How to assign a new name for values selected from two columns?

I'd like to assign a new name (either HIGH, MEDIUM or LOW) to values selected from different columns in ArcMap 10.3 I selected the two values from the two columns ("MAIN_ROCK" and "SUB_ROCKS") using ...
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1answer
45 views

How to select different values from two columns through Select By Attributes?

I'm using ArcMap 10.3. I'm trying to select by attributes different values from two columns. I want to define the areas where Main rock is GRAVEL And Sub-rocks are : a. mudstone tephra loess b- ...
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62 views

How to create a sequential unique id by groups?

I'd like to use the field calculator in QGIS to create a unique feature (polygon) id that reflects different levels in a geographic hierarchy. So say I have a REGION attribute within which there are ...
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1answer
49 views

Calculate proportions of point counts per polygon based on threshold values

I have an attribute table containing "Joint_Count" and Raster ID (A1, A2, etc), where Join_Count refers to the sum of points per raster ID. If the sum of all Join_Count represents 100%, how do I ...