Questions tagged [null]
NULL is a value for an attribute value that contains no data. Sometimes not allowed due to 'not null constraints' or slt.
182
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Remove columns with NULL values from print payout attribute table
I have an attribute table in my print layout that only includes features within the map extent. I want that table to only show columns that have non-NULL values for that feature set, i.e. if the ...
- 173
2
votes
1
answer
32
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Allowing null outputs when mapping over FeatureCollection in Google Earth Engine
I have code working that extracts the area of forest loss from the Hansen Global Forest Change dataset for each available year and attaches it to the properties of a mapped FeatureCollection. This ...
- 1,519
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18
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Why gdal_calc.py returns 0 (Zeros) instead of NaN in the output?
Why this gdal command returns 0 (zeros) instead of NaN in the outfile?
gdal_calc.py -A aa.tif --outfile="out.tif" --type=Float64 --NoDataValue=nan --co="COMPRESS=DEFLATE" --format ...
- 1,164
4
votes
1
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66
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Deleting NULL geometries and duplicate nodes from table using PostGIS
I run the command to delete null geometry from a table:
delete from table where geom is null
And delete duplicate nodes by running the command:
update table set geom = ST_Multi(ST_Simplify(geom,0));
...
- 51
3
votes
2
answers
79
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Deleting contents of all entries in field in QGIS Attribute table
In QGIS, how can you delete all of the entries in a field in an attribute table? If you go to a particular entry in a field, you can delete that entry, but how can you delete all of the entries in the ...
- 415
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17
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Gstat outputs NULL when using variogram() function
I am trying to do a kriging interpolation on a fake data set to familiarize myself with gstat. This code has worked before on a larger df but for some reason when I try to make the variogram, the ...
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1
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1
answer
52
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Prompt User in ArcGIS Pro Attribute Rules
In Attribute Assistant I have some prompts for the user to enter a value. Sometimes these fields do not have value and the field can be null. Attribute Rules don't have a prompt methodology. I am ...
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44
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Polygon on scratch or shapefile area returns null in QGIS & EPSG3857
Just got started with QGIS (the software) today and I'm getting Null for a hand-drawn polygon, even for a circle shape. Here is what I've done:
Installed QuickMapServices plugin
Installed GeoCoding ...
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2
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52
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Raster Calculator in QGIS returns -3.4e10^38 when saved
I'm using the raster calculator with the following formula: "myraster"@1-100
Now if I choose the option save as tiff file the resulting raster consists of cells with value -3.4e10^38 (...
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11
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1
answer
377
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Concatenating labels in QGIS
I am trying to display labels for polygons in a dataset. Each polygon has about 5 different fields that I want to display. Depending on the polygon, there may be NULL values in the field(s) that I am ...
- 173
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35
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How to remove fields from insert or updates in QGIS
In QGIS 3.22 using a Microsoft SQL Server database I would like inserts or updates to ignore several columns. The reason being that some columns have values generated by the database. Currently when ...
- 957
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119
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QField Geotagged Photos with NULL direction field
I have some geotagged photos taken in QField on an Android device. Whenever I import these photos into QGIS using the "Import Geotagged Photos" tool, the "direction" field is NULL, ...
- 21
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0
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77
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Apportion Polygon in ArcGIS Pro keeps getting empty outputs
I'm trying to use the Apportion Polygon tool to find the demographic characteristics of the population within 3 km of a set of point features. I used the buffer tool to make 3 km radius polygons ...
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1
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114
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Using ee.Reducer on monthly time series with missing data
I am trying to generate a value of mean MODIS LST for each month in a time series for a feature collection, as well as an overall timeseries minimum and maximum LST for each month of the year. When I ...
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1
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105
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QGIS 3.24.1 - in QuickOSM, how to import raw OSM into GeoPackage and select which tags to import?
With overpass-turbo, I made a query and exported a raw OSM file.
In QGIS 3.24.1, I import this OSM file into GeoPackage using the OSM File menu in QuickOSM plugin. It works but it imports all tags and ...
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1
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280
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In FME: how to handle NULL values in numeric expressions as 0 using the attribute manager
i stumbled across the following challenge in FME:
how to deal with NULL values if you want to perform a calculation for a new attribute. For example, I want to sum up values (could be any other kind ...
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0
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529
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NULL values after merging layers with ArcGIS Pro ModelBuilder
in ArcGIS Pro I have two point layers, "Output" and "Output_2". Using the "Near" tool, I examine which points are close to each other, select some from "Output" ...
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1
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122
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Make a loop to fill null pixels of an image with other images
I am new at Google Earth Engine and I want to fill null pixels of an image collection with pixels of complete images. In my case I want to make that in a loop, in which one the first image of a list ...
0
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1
answer
59
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Surfer Null Island data issue
I'm trying to troubleshoot why my data is going to Null Island. I'm using Surfer for the first time. I have a .csv of several dozen points collected in WGS84, UTM Zone 16N. I've verified that the ...
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150
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Use -unsetDefault to remove NOT NULL constraints with ogr/gdal
I have a feature class in a gdb that I wanted to export to a gpkg using ogr2ogr. This feature class has some null values that I want to retain and by default, there is a Not Nullable constraint when ...
- 1,873
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1
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235
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Create a geopackage file with integer attribute containing NULL values in GeoPandas
I've been asked to produce a geopackage file in a specified format where one attribute is specified to be int64 nullable, and my case includes NULL values. Trying in GeoPandas, my problem is that I ...
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1
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1
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331
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Problem with IS NULL condition in GeoServer CSS style
I have a style that divide features in PostGIS layer to four categories based on atributte Z_KAT. In the fourth category I want to specify that Z_KAT is equal to '04' OR null value.
Condition for text ...
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3
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193
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Can a Geopackage Boolean field contain a NULL value?
QGIS 3.24.3. When I create a Geopackage Boolean field, the default display is the word false, displayed in italics. Likewise, if I calculate the Boolean field = NULL, they also display as an italic ...
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579
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QGIS Raster Convert Negative Values to NULL
I have a DEM layer in QGIS and want to replace all cells with negative values to the value "NULL". How can I achieve this please?
- 49
2
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1
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757
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QGIS reads blank cells as "nan" instead of "NULL"
I use QGIS to visualise my data but I use R when I have to do many treatments on my attribute tables. (package terra)
But when I write vector data with R, the Na's appear in QGIS attribute table as &...
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1
vote
1
answer
667
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Date coming through as NULL when data type is set to "date" in csv/t
If I set the data type to date(DD-MM-YYYY) in the CSVt file the date comes through but as a String/text. But I really need it to be date type.
My CSV field looks like this:
NAME,DATE,TIME,SPECIES
...
- 21
5
votes
2
answers
656
views
Python error in Update Cursor for ArcGIS: " 'int' object has no attribute 'type' "
I am fairly new to python and am trying to make a script that looks through an ArcGIS feature class and updates <null> values to 'tbd' or 99999 based on the field type (string, double/integer). ...
- 71
5
votes
3
answers
258
views
Nullifying the whole row in data attribute table at once in QGIS
I have a situation as you can see below:
and I would like to have one row cleared completely at once. Is it possible?
- 3,965
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2
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332
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Set NULL values to 0 in specific columns using PyQGIS
I have over 20 fields and I wish to set the NULL values in the final eight fields to 0. I want to be able to do this both with the field calculator and with the PyQGIS console. At the moment neither ...
2
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1
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246
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Why $x and $y gives some results NULL and other correct values for one point layer? (on one only table of attributes)
I created a point layer starting on lines (with revised geometries) and then tried to obtained the coordinates of several point layers created from the same procedure and also joined all the point ...
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35
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Nested for: I execute changeAttributeValue in the outer loop, print it and is still NULL... but inner loop works kind of fine?
A bit hard to explain, untill now my script is:
I have a for, where:
if an "Analized" attribute is NULL, I will change it to "Parent",store a "Join Value" attribute in a ...
- 33
3
votes
2
answers
352
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Getting not NULL values from three columns in one column in QGIS
As you can see, I have three columns with the important features for me (a, b, c, d, e, f) - no matter of size. I want to copy them into new column "name". The problem is when I try to copy ...
- 33
5
votes
2
answers
415
views
QGIS constraint not null depending on another field value
Does anyone know it is possible in QGIS to add a constraint to a field not to be null, only when another field has a certain value.
For example I have a field A that can be with value 'foo' or 'bar' ...
- 93
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0
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146
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Zonal Statistics results are Null in QGIS
I am relatively new to QGIS and I am having issues with Zonal Statistics. I keep receiving NULL as my results for the median. I am trying to create a map displaying the median temperature for each ...
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2
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0
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172
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QGIS raster calculator syntax to turn `nodata` values to other values
In QGIS raster calculator, how is the syntax to refer to nodata values? Lets say I have a raster and want to generate a binary output raster with data -> 1 and nodata -> 0. There is an easy way ...
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1
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609
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Replacing zero with no data in CSV file using ArcPy cursor
I have a CSV file with zero as some of the attribute values. Trying to use cursors and replace all zeros with no data or blank values. I am able to replace any numbers. But not able to update with ...
- 1
2
votes
1
answer
69
views
How to avoid default_value in field with ArcPy cursor (e.g. row[i]=None)
Some field in field_list has default_value=1
After executing the following code, such field is filled with the value «1», but normal fields are filled «Null». How could I avoid this for the field (...
0
votes
1
answer
62
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SearchCursor from source TEXT field set as <Null> being interpreted as ' ' (writing to DOUBLE)
I am Curious about the behaviour of the SearchCursor on a server Database feature class.
the data for some of the the fields I want to read is set as TEXT, with some of those fields values set as <...
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6
votes
2
answers
1k
views
Concatenate multiple fields where some contain null values (QGIS)
In QGIS 3.18. In a shapefile attribute table, I need to create a field that concatenates several other fields with a comma delimiter. Some of those fields are NULL.
Currently my approach has been ...
- 1,051
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0
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55
views
GRASS QGIS v.vect.stats returns NULL for all polygons
I'm running v.vect.stats from Grass using the processing toolbox in QGIS to take an average of a point layer attribute for points falling within a set of polygons.
After running the algorithm a ...
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228
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Filtering NULL values in date field in QGIS [duplicate]
In QGIS 3.16.9 I would like to find all the locations that have a NULL value. It is for a date field in the field services Drains dataset. I have been searching the use of NULL around various forums.
...
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1
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200
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Using .CSV file as an external dictionary, but can't find a way to reference/make a key for Null in order to assign it a value using ArcPy
I am using ArcGIS Desktop: ArcMap 10.8.1 and using Python 2.7.18. I have a script that uses a .CSV file as an external dictionary (opposed to creating a dictionary within the script) but I cannot find ...
0
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1
answer
724
views
What VBScript can I use to populate a field with text using the ArcGIS field calculator?
I need to populate one field in the attribute table of a File Geodatabase with text. Every entry in the field is set to a Null value and text entry isn't conditional upon any other factor. Every entry ...
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4
votes
1
answer
848
views
Concat fields which are not NULL
I am using the concat function in QGIS 3.16.6 on Mac.
I want to join several cell values into one new cell.
With the concat function it is ignoring cells with NULL but it doesn't separate the cell ...
- 41
3
votes
1
answer
85
views
Changing 'NULL' value to '0' in label formula
I have a label formula in QGIS that shows the name of a polygon and the remaining km of survey left to do:
"Name" || '\n' || round("Length_km_sum", 2)
But when I have an area ...
- 379
2
votes
1
answer
303
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QGIS displays NULL values as zero in the layout tables
I use QGIS 3.18.2-Zürich to display the table in layout mode. My table contains two fields of type Double. If I set the values to Null (None), a zero is displayed instead of an empty cell.
What should ...
- 7,016
2
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1
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253
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GeoPandas imports NULL attribute values as zeros from shapefile
I would read a shapefile as GeoPandas DataFrame using:
import geopandas as gdp
df = gdp.read_file('file.shp')
When I read the file, the NULL values have been loaded as zero. I need to see and ...
- 65
10
votes
1
answer
185
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Selecting NULL or date values by Expression in QGIS
How can I select by expression from a date field in a shapefile, dates that are NULL or >= 2020-01-01?
This doesn't work, it only selects those with dates >= 2020-01-01, not the NULLs
"...
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0
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42
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Changing null / no data values [duplicate]
I have a raster where null values are stored as -9999. I want to change these to 0.
Googling suggests this can be done in the raster calculator, but e.g. (layer name = -9999) * 0 doesn't work. And ...
- 63
1
vote
1
answer
90
views
Getting multiple column values at the same time in QGIS using Python
I need to filter multiple column values using python in QGIS. I am facing issue while writing expression using QgisExpression(qgis.core).
If one of the column values is NULL then also I need to get ...
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