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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Using Calculate Field (Data Management) tool to calculate 3D Length in ArcGIS 10.1

I'm relatively new to the world of model builder and scripting, so it's likely there is a very simple solution to the question I've been trying to figure out. I'm trying to create a tool that takes ...
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4answers
3k views

How to concatenate numbers and add in leading zeros?

I have three text fields populated as follows: 1, 9, 1 that I need to concatenate into a field that looks like 01.09.01. Getting to 1.9.1 is easy but can anyone help out with how to formulate it so ...
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1k views

Unit of $length in QGis Field Calculator

I'm calculating field of various features in my shapefile using QGis. I'm getting some sample length as 0.134914579766986. I want to know in what unit (eg: meters, km etc) is the above value ?
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681 views

Why does field calculator expression sometimes return a binary value (0 or 1)?

I am running simple field calculator expressions and experiencing some of the silliest results I have ever seen. I am working on census data (living as a shape file) and trying to perform a simple ...
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2answers
1k views

arcpy: check for same record in cell above and below

After using the find duplicates in arcmap 10, I want to check if the feat sequence ("find duplicates" marks all records with the same attributes with the same number [in "feat_seq"] and creates a ...
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1answer
1k views

Qualifying field names in field calculator

I am trying to set up a quick model that: Takes a point feature layer of development projets (a table in an access database with xy coordinates), Spatially joins polygon neighborhood designations to ...
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1answer
235 views

Calculating Percentiles in ArcMap?

I have a large polygon dataset (26,000) records with numerous attributes columns. I wish to calculate the percentile rank of each attribute. Say I have population_density in an attribute, is there a ...
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1answer
99 views

Area calculation of an object without coordinates

I have a photo of an object with a scale and I want to calculate its area. I guess I have to create a polygon of the area to be calculated to use the 'field calculator'. But how do I tell the program ...
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1answer
357 views

Debugging Visual Basic Code Block in calculate field using ArcGIS Desktop?

From time to time, I have to use Visual Basic in Calculate Field. As the code get bigger, the more complicated is to debug it. And ArcGIS (9.3) does not help as the error messages are, in the best ...
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4answers
8k views

Why doesn't the Field Calculator work in ArcGis 10?

When I try to calculate a field nothing happens. I have always been able to just select the field, open the field calculator and type = and the new number. This is frustrating because the other GIS ...
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1answer
414 views

How to use QGIS field calculator in python?

I would like to use QGIS Field Calculator in Python to update the existing column based on certain conditions? How can I do this?
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292 views

Is there a way to close a geoprocessing operation when the dialog box has been hidden/pushed to the back of the window

Is there a way to close a geoprocessing operation when the dialog box has been hidden/pushed to the back of the windows? I ran a python process as VB Script and when the error message appeared I ...
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2answers
153 views

How I can reverse numbers in a string without reversing any text? [closed]

I have a string, I need to reverse just the numbers in the string without the text: String: [321 test] The result will be: [123 test]
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2answers
994 views

Round decimal number in ArcGIS10.1

How can I round the decimal number in a table in Arcmap: e.g. how can I set it to 2.60?
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3answers
258 views

ArcGIS 10.1 : Returning shape.area in my code block

I try to calculate a field using an 'if' statement in the field calculator. Here is my code : " #Expression MyField_2 = def Reclass(!MyField_1!) #Parser Python 9.3 #Code Block def ...
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2answers
187 views

Problem using field calculator to add numbers in new field with preceding zeros

I wish to add a field in an attribute table that should work as a georeferencing key. It needs to take into consideration values from a series of fields. The last field is a housenumber and it ...
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2answers
2k views

Forcing decimal numbers to use comma in ArcGIS Field Calculator?

Can I add the comma "," to force the decimals to remove from the attribute and replace with the number? For example, I have an Acres field column that says 506320.0750 and I want to replace the ...
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1answer
2k views

What expressions for QGIS field-calculator?

I do not understand what language I have to use in field-calculator and labels on QGIS: SQL or Python? And where I can find the possible script/expressions to use? in the image you can see the ...
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3answers
366 views

Count the number of characters in a field (Python)

I have a field that contains street names and a second field called COUNT. I need to perform a Python field calculation on the COUNT field that counts the number of characters in the STREET_NAME ...
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5answers
303 views

Easy way to sum up a lot of values?

I've got a shapefile that was made by the mother of all Unions. Because of that, it's got about 400 columns, and I want to sum about 100 of them (specifically, the "Score" from each). Is there an ...
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2answers
230 views

VB Script or Python for Field Calculator when using greater/less than?

What I have: I have 4 fields for my address ranges. L_ADD_FROM, R_ADD_FROM, L_ADD_TO & R_ADD_TO (all in DOUBLE field type). What I need: The lesser value from L_ADD_FROM and R_ADD_FROM to ...
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2answers
153 views

Using Field Calculator to append attribute

I have a field containing the file names for photos. I need to add the folder location to the beginning of each file name. Anyone know the code for doing this in Field Calculator?
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Calculate Field Syntax: If statement over many fields

Apologies if this has already being asked but I couldn't find a page pointing to this problem. I'm struggling with the python syntax in the Calculate Field so that, in the table above: if b, c, d, ...
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2answers
2k views

Use output of Add Field as input for Calculate Field in ModelBuilder

I have created a simple model in ArcGIS 10 which, after some initial processing of a feature class, outputs outputfc and adds a field to it. Regardless of the feature class input (which the user ...
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3answers
228 views

Calculate field using variables as fields

When I calculate a field like this: field_0="field_name0" arcpy.CalculateField_management("Layer", field_0, '!field_name1! / !field_name2!', "PYTHON_9.3") It works! The field "field_name0" in the ...
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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 ...
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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 ...
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2answers
7k views

Using conditional statements in Field Calculator

I have two fields, "P_Area" and "PC_Area", whose sizes I'd like to compare in a third field, "Areas_Equal". The "Areas_Equal" field should contain a "Yes" if the other two are equal and a "No" if they ...
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3answers
230 views

Calculating file name with field calculator

Is it possible to calculate the file name in an attribute table? My shape file has a name like "cities.shp". In this shape file I want to have a attribute "cities").
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1answer
325 views

Adding an “m” to the end of every number in a row

What function do i need to use to add an space and an m after every item in a row, using the field calculator in the attributes table. I have a load of numbers (as strings) and would like to add m ...
3
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1answer
606 views

Using Python in Field Calculator to compare two fields

I'm trying to use field calculator to compare two fields in a table of tax parcel data, Land Value (LAND_VAL) and Improvement Value (IMPRVT_VAL). My goal is to determine (1) Parcels with land value ...
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3answers
1k 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 ...
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2answers
536 views

Python find string with two decimal characters

I have two columns in a personal geodatabase table that I'm trying to add up (to a third field) using a python function in field calculator, however some of the string values are not real numbers. ...
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2answers
1k views

Why is ICalculator.Calculate significantly slower than the CalculateField geoprocessing tool with SDE datasets?

I just discovered today that there are essentially two ways to calculate field values in ArcObjects: 1. Using ESRI.ArcGIS.GeodatabaseUI.ICalculator: ITable table = …; ICursor updateCursor = ...
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1answer
3k views

How to count and record the number of entities with the same name in the field calculator?

I have a question with ArcGIS 9.2. In an attribute table the column [name] includes the name of every place in this layer. Next to that (in columns [numbers]) there should be recorded how often a ...
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4answers
1k views

Field Calculator in ArcGIS - keep equation

I'm using Arc 9.3.1 (Arc Editor). In edit mode I've created a simple field calculation. For example's sake let's make it [Field3] = [Field1] + [Field2] How do I 'keep' the calculation so Field3 ...
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2answers
544 views

How to calculate a value based on another field under arcpy.da.UpdateCursor and cursor.updateRow?

I am trying to do a calculations under arcpy.da.UpdateCursor. I want to calculate the values for the records that have FIPS=06037. I want to take the values from "kg" column and populate the new value ...
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135 views

How to pad field with blank spaces using calculate field tool of ArcMap?

I am trying to pad the right side of a field with blank spaces so that when I label the field, it labels further over to the left. The only way that I can seem to make this work so far is by adding a ...
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1answer
248 views

Calculate average value for each row

The picture is an example, but the method would be the same at mine bigger dataset. So i have some parcels with each a ID value and some fields. such as field 1, field 2, field 3, fieldd 4,... with ...
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161 views

How To Determine Percent of Matched Data?

In my attribute table, I have 2 columns with qualitative (categorical) data. Both of them are from different sources so I am trying to find the percent of matched data from these 2 columns. I created ...
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1answer
112 views

How to find lowest value that is not null using Python in ArcGIS for Desktop?

I have four fields in my table, (A,B,C,D). The field type is double with some fields being NULL. I used min(A,B,C,D) to return the smallest value and it works well if there are no NULL value in any of ...
3
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2answers
753 views

If-Then Statement in Field Calculator

Scenario: I have four fields: A, B, C and D Field A is text-based and contains values from '000' up to some number 'xxx' Field B contains a set of values (also text, but represented by numbers) ...
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1answer
890 views

Calculate attributes to table based on other attributes

I am going through thousands and thousands of road lines and giving them a value based on QC with imagery. So for instance for the add_data field I give it one of these five numbers: 0 = not ...
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2answers
84 views

Averaging XY data for locations in QGIS

I wanted to find out mean of the selected point using QGIS. I tried out selecting using attribute table but could not find an option for mean in field calculator. I have attached a screenshot with ...
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1answer
161 views

QGIS - Is it possible to increase Output Field Name?

When creating a new Column, the default value for the length of the name is 10. Using the Field Calculator via the Model Builder, I want to include the names of regional areas into the columns which ...
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1answer
909 views

How to use the field calculator's centroid() Geometry function in qgis 2.0?

There is an option in the field calculator for centroids under geometry which when you double click gives you "centroid( ". What information is required here in order to use this function?
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691 views

Adding VBA into a Python script generated by ModelBuilder

I have created a model that does a calculate field and have used VBA in the code block. But when I export it to Python, it doesn't work. Here is the VBA code: new_value = ...
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Which python function should I use to populate a string field based on a numeric value from a numeric field in ArcGIS Field Calculator

I am new to Python and I'm trying to write a simple if then statement in Field Calculator in ArcGIS 10.2.2 that will take the values from a numeric field and add them to a string field. I can't ...
3
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2answers
218 views

Expression to calculate and sort data from several layers into one layer

I am trying to develop an expression whereby one layer can add data from 2 other layers and then rank them, is this possible? I have also tried the problem with using just 1 layer but I cannot work ...
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623 views

How to create button that calculates acres on selected polygon features?

I'm looking to create a simple button that calculates acres on selected polygons and can't quite find what I'm looking for. I read through this thread: automating a python script..., but found it ...