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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3
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1answer
521 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?
0
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0answers
184 views

Using Field Calculator to Calculate a Mean for Multiple Rows

I am trying to calculate a mean across a multiple number of attribute rows and have this value added to a new field that I have entered in the attribute table. I have an attribute table which has a ...
1
vote
2answers
166 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 ...
6
votes
1answer
2k views

How to perform If Statement in Field Calculator of ArcGIS for Desktop?

I have a shapefile containing two numeric fields ("Dist_1" and "Dist_2"). I want a Field Calculation that will populate an additional field ("Result") with one of three answers: First if Dist_1 is ...
1
vote
1answer
97 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 ...
0
votes
1answer
221 views

Arcpy CalculateField using formatting syntax

I have 2 feature classes (FC) that I am merging together and then performing some field calculations on. The 1st FC has 100k+ records in it, and the second FC is a blank FC that I'm using as a ...
2
votes
2answers
163 views

Correctly calculating attribute table column in gvSIG

I am trying to conduct a multicriteria evaluation, and it is necessary to check the compatibility of two different land-use types that I have in seperate layers. I am working in gvSIG 1.12, and have a ...
2
votes
1answer
219 views

How can I refer to a model variable in a Field Calculator or Pyculator formula?

I am new to QGIS 2.0.1 Modeler (Sextante) and not very able in Python programming. My question regard the use of field calculator (or advanced python field calculator) inside the modeler. Is it ...
1
vote
1answer
190 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 ...
0
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0answers
80 views

Import csv file and use “toggle editing” and “field calculator” without Saving it as a Shapefile.

I am importing a .csv file in QGIS and I have also made the *.csvt file where I have specified my data types. I still cannot use "Toggle editing" and "field calculator".Whether I must save it as a ...
2
votes
1answer
358 views

Calculating a field based on two other fields, if they exist [duplicate]

I'm using ModelBuilder to iterate through ~800 shapefiles to add and calculate a new field (I'll call it Field_A). Field_A needs to be populated by either Field_B or Field_C, whichever exists. Half of ...
1
vote
1answer
241 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 ...
1
vote
1answer
240 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 ...
4
votes
2answers
151 views

Can Hyperlink be based on two fields for path and file name separately?

I need to create a hyperlink field. I have one field with the file name, and another field that contains only part of the file path (the real path is unknown). The table contains 14,000 records with ...
3
votes
1answer
471 views

Calculate Field python code has “Expected end of statement” error

I am creating a line shapefile from a csv in a Python (2.7) script. I am assigning an ID field from the csv to a variable and then later using it in the Calculate Field tool. The ID field originally ...
0
votes
1answer
121 views

Problem in calculating length

I am Digitizing road line in India using open layer plugin.When I calculate the length of line using field calculator it gives me the result in millimeter . I thought it is the projection problem and ...
2
votes
3answers
559 views

How to count occurrences of one field grouped by values of another?

Is there a way of calculating the number of unique text strings in a field in ArcGIS 10.1? I have a number of repeated strings in this field, but would like to calculate the number of unique strings ...
2
votes
2answers
918 views

Use Feature Class “Name” from Iterate Feature Classes to Calculate Field with Model Builder 10.1

My goal is to create shapefile that contains merged feature classes from a geodatabase. I would like for there to be a new field in the resulting shapefile that contains the name of the original ...
5
votes
2answers
184 views

Field calculator script to work out first 5 dominant area fields?

I have 5 fields of different landcover types with areas of each and found below: > PRC_Water| PRC_Bare| PRC_Urban| PRC_LVeg| PRC_LVeg| > 5 20 40 20 15 I have ...
2
votes
3answers
618 views

Python script for identifying duplicate records (follow up)

I am trying to calculate a field that marks duplicates and sequentially numbers them. I am using the code below that I found here: Generating sequential numbering for duplicate values in a field ...
1
vote
0answers
665 views

Using multiple fields for a Reclass calculation in ArcGIS Field Calculator [closed]

I am trying to create a dummy variable from an existing dataset using ArcGIS's Field Calculator tool with a Python script. My conditions require the use of multiple fields to determine the output ...
1
vote
2answers
123 views

Creating a new integer field based on text in a different field - ArcGIS 10.1

I need to create a new integer field based on another text field. All instances of a the same text string in the existing field should be assigned the same number (starting at number 1). Can I do this ...
1
vote
3answers
463 views

Why do area calculations return negative values?

I have created a shapefile with some polygons and am now trying to calculate the area of these polygons. The original CRS was WGS84, I have reprojected it to WGS 84 / World Mercator so unit is metres. ...
1
vote
2answers
280 views

How to use centroid option in Field Calculator in QGis

I want to use Centroid option in field calculator in QGis .How to access it?
2
votes
2answers
278 views

Is the derived area/length/xy values of a polygon/polyline layer in QGIS usable?

I have a raster that is projected to a state plane CRS and I am adding polygon/polyline shapefiles that are projected to WGS84. On the fly transformation is set to reproject to my raster CRS. When I ...
1
vote
1answer
149 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 ...
2
votes
1answer
305 views

Generating sequential numbering for duplicate values in a field sorted by ObjectID

I am trying to figure out a solution to an field calculation problem. What I'm trying to do is automatically (using either ArcPy or the Field Calculator) generate sequential numbers, beginning at 1, ...
1
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1answer
139 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 ...
5
votes
1answer
327 views

Translate Excel formula to be used in field calculator

I have a series of equations to create corner points to make rotated polygons based on angles in the attribute table, but I have created it in excel and can't figure out the syntax to get it to work ...
0
votes
1answer
160 views

Python: using CalculateField_management for duplicating attributes with a double quotation mark

I am writing a python script which duplicates a field. The field contains names of pipelines but some of these names has double quotation (ex. 8" NGL PIPELINE). I have created a new field and trying ...
0
votes
2answers
184 views

Field Calculate with a function written in python within a larger python script

I'm writing a python program where I need to field calculate using a python function. The function takes two strings; one used for an if statement and the other to become an integer complete a simple ...
2
votes
1answer
355 views

How to use Field Calculator to calculate area as percentage?

I am searching for python code to use in Field Calculator to calculate area as a percentage in relation to another field? The area percentage needs be calculated based on the total area for each ...
1
vote
3answers
151 views

Conditional Statement for attribute data

I'm trying to write a conditional statement that references another field within the same shapefile layer. I want it to only do so if the one field is " Null " and leave is alone if there is already a ...
2
votes
1answer
146 views

Using Sum() or something similar with CalculateField_management and FieldLists

I need some help with using variables with CalculateField_management tool. I've tried several different scenarios but don't seem to have any luck. What I have is a list of fields containing water ...
1
vote
1answer
152 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 ...
3
votes
3answers
167 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 ...
2
votes
2answers
51 views

How to flag parcels as being within stop type dependent distance of transit stops?

first question here! I have a parcel layer and a transit stop layer. The transit stop layer has different bus stops, light rail stops, etc. I want to add to my parcel layer attribute table fields ...
1
vote
0answers
54 views

How to measure area of polygons generated from gps data in qgis? [duplicate]

Somebody classified my question as a duplicate. But applying the answer doesn't work for me. Here is what I did: - I made sure that my layer is in a projected coordinate system (UTM30N, WGS84) - I ...
2
votes
1answer
155 views

Using update cursor on a field with a domain

I have been replacing field calculations with python update cursors in many of my work flows and today I ran into a problem. The fields being updated have an attribute domain. so now, when I ...
0
votes
3answers
255 views

Why does CalculateField set values to <Null> when output extent is in a different coordinate system?

I'm quite new to ArcGIS, and now I have to work on a script that goes through a list of feature classes to: add a field to their attribute table and fill that field with a number that I retrieve ...
1
vote
2answers
174 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 ...
0
votes
4answers
152 views

How can I calculate different polygons by different attributes?

I'm doing my master thesis and want to calculate different polygons (in QGIS 1.8 for Mac) in four different columns which I defined by different attributes. i.e. some of the attributes in the first ...
4
votes
3answers
150 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 ...
0
votes
1answer
1k 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 ...
1
vote
1answer
106 views

How to write a expression in field calculator for finding $X and $Y?

I'm trying to calculate the lat/long of points using the Q GIS field calculator.Nathan W suggested to First, save the layer as WGS84 and import it again. Then in the field calculator you can use $x or ...
0
votes
1answer
64 views

Table calculation in QGis

I have a shape file with the attribute "yield". I need to know the math difference between yield (id1) and yield (id2)...then yield (id2) and yield (id3) and so on... I hope you understand what I ...
1
vote
1answer
836 views

ArcGis File Geodatabase with Null values (Field Calculator)

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( ...
0
votes
1answer
117 views

Trying (+ failing) to use a Function in Field Calculator

I'm trying to populate a field using a function. When I run this in Pyscripter, it works fine: d = {} # Function # def find_dups(val): d[val] = d.setdefault(val, -1) + 1 return d[val] # ...
2
votes
2answers
1k views

Using Value from Iterate Feature Selection to Calculate Field in ArcMap 10.1 ModelBuilder

I have two polygon feature classes, an alignment layer and a parcels layer. I am trying to use ModelBuilder to create a tool that will do the follow: iterate through groups in a single field of a ...
2
votes
1answer
157 views

Need a Python field calculation that works like the DatePart( ) VB Function

I have a field called Abandoned Year (short integer data type) that I am trying to populate with a four digit year from a column called Decommission Date (Date data type). I have done this in the ...