Field calculators (which are available in QGIS, ArcGIS-related products, etc.) can recalculate the values of a single field, on all, or selected records within a table based on a symbolic expression.

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1answer
58 views

using “abs()” function in QGIS field calculator?

I'm pretty new to GIS in general and I'm trying to take an absolute value of the difference between two fields in field calculator when creating a new field, but using ABS () returns an invalid ...
5
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3answers
997 views

calculating a field in which null values may be present

I would like to calculate a field (short integer) using other fields (short integer) present in the table. In some cases these fields may have null values for one or more of the fields. For example, ...
1
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1answer
96 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 ...
1
vote
2answers
281 views

How to write a QGIS regex for rounding to two places after the decimal point?

In QGIS field-calculator round() is not working in QGIS 1.8 so I try to do the following with a regex: I'd like to keep the first two places after the decimal point - where do I go wrong? ...
0
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2answers
114 views

Stacking attributes in a text field

I am trying to stack my text in an attribute table using the field calculator, but it does not seem to be working. My field name is: Facilities. My attributes are in this format: Public ...
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2answers
365 views

ArcPy Field Calculation with special characters

I'm trying to calculate a string field, using "µSv/h". Running this in the manual field calculator works just fine, but I've tried this in the Python window in ArcMap as well as the IDLE, but both ...
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4answers
1k views

Field Calculator: Add “0” to the front of all values in a column

I have a table for each state with Zip Code values. The 5-digit Zip Codes that start with "0" have been reduced to 4-digits. I cannot figure out how to add a "0" to the front of all the values in the ...
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0answers
193 views

python script to calculate and return values based on several conditions

I need to calculate and return the value "continuous" to those records in a polygon feature class with species records aggregated to a UTM grid considering the attributes are species name, grid code, ...
2
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1answer
92 views

How to convert QGIS Field Calculation to ArcGIS?

I have a field calculator expression I use in QGIS to generate unique IDs that are sequential, but start with a text string. I now need to perform the same thing in ArcGIS, but I am unsure of how to ...
2
votes
2answers
144 views

How to calculate land cover inside the buffer zones?

In one Shape file I have created 1200 buffer zones Around coordinates. I created a field and calculated the buffer zones area in hectares. Then I clipped different landcover layers to the buffer ...
2
votes
2answers
427 views

Field calculator or update cursor?

I have a feature class in which one field (let's call it "Field_A"), as yet empty, is to be populated by the contents of another field ("Field_B") multiplied by a certain number (I'll call it the ...
1
vote
1answer
74 views

How to fill inn A, B, C …Y, Z, A, B, …Y, Z, A, B, and so on? [duplicate]

as a second part of a problem i am trying to solve. I need help to figure out how to fill in serial letters.. Starting at A.. going to Z and starting over at A again.. I have a tabel with numbers ...
5
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4answers
623 views

How do I fill in serial letters (AA, AB,AC…,BA,BB,BC…ZZ) to a shape?

(I am using ArcGIS software, ArcMap...) MY PROBLEM I have a shape file containing points. The shape file contains 3 columns named FID, Shape* and Label. In the column I want to fill in AA, AB, ...
0
votes
1answer
560 views

How to calculate polygon areas in acres or square miles instead of feet?

I have a layer in State Plane NAD83. When I use "Vector|Geometry Tools|Add/export geometry columns" or Field Calculator they both create the area in feet. What if I want acres or square miles? Thanks ...
6
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3answers
1k views

How to replace non-English characters in attribute tables using Python?

I have a few shapefiles where some of the attributes contain the non-English characters ÅÄÖ. Since some queries doesn't work with these characters (specifically ChangeDetector), I tried to change them ...
1
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2answers
117 views

How to get a string from a Double with a fixed number of decimals?

I have a featureclass (in a File Geodatabase), with a particular field of type Double. I want to copy it over to a text field, so that only 3 decimal places are shown. For example: 34.78902345 ...
2
votes
2answers
216 views

Capitalizing The First Letter Of Each Word In Attribute Field

Does anyone know of a way to capitalize the first letter of each word in a field in an attribute table? I am doing this in QGIS. I know of field calculations to change all the words to Lower or ...
0
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0answers
29 views

Exporting QGIS attribute table to excel [duplicate]

I have a million rows in the attribute table, with lat/lon columns that I want to export to Excel. Selecting all the rows causes QGIS to crash. Is there another way to do the export? The million rows ...
1
vote
1answer
488 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 ...
6
votes
1answer
3k views

Calculate area within Python script in Arcmap

I am trying to calculate the area of a polygon within my Python script. I create a new polygon from merging two together, and I'd like to add the area of the resulting polygon to a field in the output ...
1
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2answers
352 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
3
votes
1answer
881 views

Why does Field Calculator return 0 values when decimals are expected?

I realize I posed this question, and got answers, several days ago (see (Field calculator error)) , but none seem to really be working, and so am posing again. Below are two screenshots that show the ...
3
votes
3answers
263 views

Field calculator error [duplicate]

NOTE: This problem is similar to one that was answered here: Why does Field Calculator return 0 values when decimals are expected? I'm relatively new to python, and am trying to run a simple field ...
3
votes
2answers
347 views

QGIS Field Calculator Results Removed When Saving Edits

Mac OSX 10.6.8 QGIS 1.8.0 : Using the field calculator from the attribute table, the $area of each feature is shown nicely in the table until I try to save it, then all the values are replaced by NULL ...
0
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0answers
55 views

Replace Null Values Field Calculator [duplicate]

I am using ArcGIS 10 and have a polygon shapefile in which many of the numeric fields are Null. The polygon shapefile in question is produced by joining a polygon shapefile with a point shapefile and ...
2
votes
1answer
356 views

Am I over-complicating adding and then calculating fields? Suggestions for a better way? (Python)

I'm attempting to re-position a question I asked yesterday here. I am starting to think that the way I wrote my code just isn't the best way. Am I overcomplicating things? I know for a fact that ...
2
votes
1answer
779 views

Incorrect field name resulted in RuntimeError: ERROR 999999 (Also, better code for adding and calculating fields)

This is the bottom half of my code (and it's been edited somewhat to share publicly). The code works perfectly fine when the fieldList has only three fields in it, but when I populate it with all 108 ...
2
votes
1answer
237 views

Calculate field result is float with Arc tool, integer with arcpy script

I am trying to calculate a field for some points within a python script using arcpy functions. (This is calculating the percentage visibility from a cumulative viewshed, if that matters.) # Process: ...
0
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5answers
2k views

Changing null value to specific numbers in ArcGIS for Desktop? [closed]

I have a Excel file showing annual precipitation and I add it on arcmap. When I tried to check it's attribute table the field calculator is passive. I want to change all the Null value to specific ...
3
votes
2answers
217 views

How to create a label formatted like “ 1,000' ” from a numeric field?

This question builds on a previous question I came across at gis.stackexchange: How to easily edit attribute data using Regular Expressions? Perhaps someone can point me in the right direction? I ...
0
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0answers
26 views

I need to add one table to another table as strings.

But all of this two table data is numeric. And one of them is float. So I need to add from the float table only integer and merge it with other table. What to write in field calculator?
0
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0answers
321 views

How can I get shape filename in attribute field using field calculator with VBA?

I want to store ths shapefile name in an attribute field using the field calculator and visual, but can't find the way to do it. Can anyone help me, please? Thanks!!!
2
votes
1answer
900 views

Using the Field Calculator in a Domain field

I have a coded domain field with 10 dropdown options. Possible choices include integers and text. I need to change a selection of 250 features (which have differing values) to the same value. This ...
1
vote
1answer
873 views

Delete first two letters from a string field

I'm looking for a field calculator python statement to delete only the first two letters of string entries. For Ex: !Name!.strip([0:2]) I know this syntax is incorrect. Thanks a lot
0
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0answers
64 views

How to populate polygon extents to an attribute table in QGIS

Is there a way to calculate the XMIN, YMIN, XMAX and YMAX of a polygon and write it to a field in an attribute table? The Geometry functions available in the Field Calculator are for points. ...
2
votes
1answer
203 views

Mysterious Invalid Syntax in Field Calculation

I'm trying to calculate a field in Model Builder using the Calculate Field tool. I'm using the following code block and expression in the calculation, but am getting an "invalid syntax (, line 1)" ...
4
votes
2answers
435 views

Field Calculator decimal places - how can I limit them?

I've added a new column to an attribute table and performed an operation with the field calculator to populate the new column. The result is a column with a percentage. My problem isn't major but I ...
0
votes
3answers
359 views

How can I easily detect gaps in a polyline using arcmap 10.0 (arcview license)?

I'm making routes by selecting links from a streets layer which I export as a new temporarely layer in arcmap 10. This layer which I call route_temp unfortunately can be very long and contain gaps, ...
2
votes
2answers
428 views

Type mismatch error in Calculate Field tool in ArcGIS 10.1

I'm trying to run a rather lengthy model (built in ArcGIS 9.3.1) in ArcGIS 10.1 and I'm recieving an error on a Calculate Field tool. The error is - Type mismatch: 'iif'. This error is refering to ...
5
votes
1answer
269 views

How to add attributes in proportion to intersecting area from another layer

I am new to using QGIS. I have two polygon layers: Voronoi of Access Points Census block maps with population I want to get number of people covered by each Access Point (Assuming uniform ...
2
votes
1answer
106 views

Syntax question for ArcGIS ICalculator object

This is a silly question, but I have this code snippet that I can't figure out: 'Define a calculator for NewArea field pCalculator = New Calculator With pCalculator .Cursor = pCursor ...
1
vote
1answer
503 views

Arc 10 Python .shp attributes - usings fields to populate other fields - if/then/else statement

Ive been looking for a solution and unable to find one so please help if able: I'm trying to avoid manually inputting Begin and End engineering station values already inputted into a seperate field. ...
4
votes
2answers
172 views

ArcMap: Calculate Quarter using Date field

I am using ArcMap 10.0 and making a map where I symbolize on annual quarter (i.e. Q1 2013, Q2 2013, and so on by quarter through 2015). If a date field contains this: 01/15/2013, and I wanted to ...
-1
votes
1answer
226 views

Field Calculator Does not Work in Arc10

I'm having a problem, described below, with Field Calculator in ArcGIS 10. I wonder if there is a known fix at this point. I'm updating to 10.1 soon, but this work cannot wait until then. Details: ...
0
votes
1answer
263 views

Add sequence numbering based on attributes in a table [duplicate]

Is there a way to auto populate a sequence of numbers based on another attribute in a table? For example, if field "Name" has a sequence of numbers from 1 to 10, and I want to number all the rows in ...
2
votes
1answer
565 views

Using Python in the Field Calculator, how do I refer to a field in another shapefile?

I want to compare the changes in geometry between two shapefiles (of election districts in NYC. One is from 2001 and the other 2005). I am attempting to calculate a new field in the 2005 shapefile ...
3
votes
1answer
2k views

Using Python to Calculate a field

I am trying to replace values in a single column using an else if statement, but I keep getting an Syntax error in line 2. I'm new to Python so it's probably an easy solution, but I haven't been able ...
5
votes
2answers
152 views

Using field calculator to delete specific contours

I have 3 contour shapefiles with 25m, 50m and 100m equidistance. Now I want to delete in the 25m-shp-file every **50m and **00m contour and in the 50m-shp-file every **00 contour. How can I show them ...
3
votes
3answers
752 views

Auto-calculate field (area or formula)

I'm wondering if anyone has any insight into the potential to auto-calculate the value of a field, either area or distance (ideally) or a formula (based on the values of say 2 other fields, or an ...
4
votes
3answers
673 views

How to insert a quotation mark through the Field Calculator of attribute table of a Shapefile?

I have a shapefile of polylines with information of diameter. But the problem is that i didn't enter the inch sign(") with the values of diameter. What would be the solution that qutation mark would ...