Python is an open source interpreted programming language used in many GIS programs.
0
votes
1answer
20 views
How do I use python to populate values in one field that represent values of another?
I am trying to populate a field with a sorting code that represents the value of another field. Example:
EXPCODE|SORT|
S4DNN2 |3.5
H2BNN2 5.0
EXPCODE is a field with a value like "S4DNN2." SORT ...
-2
votes
0answers
15 views
Grouping string values [on hold]
I stuck at grouping attribute fields with text format. I want to group this strings depending their content. e.g. assume 12ac9, 14ad8, a4ad7 are three different value in this attribute field. I want ...
0
votes
0answers
14 views
PyQGIS: subtracting two values and append ID to list
I would like to subtract two values retrieved from qgs feature iterator objects and append the value of the feature id to a list depending on a condition.
I have two layers:
roadsLayer
pathsLayer
...
1
vote
1answer
31 views
Getting and using XY centroids in ArcGIS Field Calculator using Python Code Block
I am writing a script to obtain Grid reference but cannot fathom how to get XY centroids without creating new fields (all examples I have found are based on writing XY centroids to field).
Here's ...
0
votes
1answer
25 views
Project only required shapefiles in folder - update [duplicate]
I have updated the script from my previous question;
Project only required shapefiles in folder
I cant get the if fcspatialRef != spatialRef: to work. The script won't filter the shapefiles in ...
2
votes
0answers
11 views
Not able to get the PostGIS Layer Viewer running in pgAdmin or command line
I've installed PostGIS Layer Viewer as a plugin for pgAdmin. I've downloaded postgis_viewer.py from the official repository on GitHub! and followed the install instructions described on Web site!. ...
3
votes
2answers
39 views
Image processing using Python, GDAL and Scikit-Image
I'm new here and I'm sorry if I do something wrong.
I am struggling with a processing and hopefully I will be able to solve here.
I work with Remote Sensing applied to Forestry, especially working ...
1
vote
1answer
36 views
Using defined function code block with Python in ArcGIS
I am running a Field Calculation within a Python script in ArcGIS. Within this Field Calculation I am calling a defined function within a code block.
Here is the dialogue that I ran and works:
...
2
votes
1answer
40 views
QGIS Python - raster as point layer, coordinates issues
I would like to create point layer for storing values retrieved from a raster file.
My idea was to iterate through all raster cells. If cell value is different than NULL, I wish to create a new point ...
2
votes
2answers
70 views
How to add multiple python expressions in field calculator
How would I add multiple python expressions in the ArcMap Field Calculator if possible?
I tried separating each expression on a new line and also separating with a semi-colon but neither worked.
...
0
votes
0answers
12 views
Implement r.cross / ArcGIS Combine with GDAL
I am using GDAL to process a lot of rasters. I then need to combine all the arrays to create a single output raster that represents all the unique combinations of values.
I.E the same thing as ...
0
votes
0answers
16 views
QGIS 2.8.1: crashes with standalone install of python
I have QGIS 2.8.1 installed, as well as python 2.7.4.
Qgis is crashed on the 'python load', if it can find the folder for python. If it change the folder name of 'python', it will use its version of ...
1
vote
0answers
18 views
Running Python outside of QGIS - (ImportError: No module named qgis.core)
I'm trying to run simple scripts on QGIS from outside the QGIS environment - as here
How to run a simple python script for QGIS from outside (e.g. Sublime Text)?
My code:
import sys
...
2
votes
1answer
46 views
Python GDAL: ogr.open or driver.open?
I’ve been using GDAL with python to manipulate shapefiles. When opening a source file I first set the driver to “ESRI Shapefile” before calling the driver’s "Open" method with the required shapefile.
...
1
vote
1answer
33 views
Using a for loop to execute a query in arcpy
I'm trying to provide the breakdown of fire detection for an area by sorting of confidence levels. The dataset has 12 files (one for each month in a year) with fire records which all have a column ...
3
votes
1answer
49 views
Force OGR to use specific driver for input format
How could one force ogr2ogr to use a specific format to read input files?
Out of the box ogr2ogr automatically chooses from it's long list of formats, which most of the time is great. However today ...
1
vote
2answers
47 views
How to add “0” to multiple parts of text value in Field Calculator with Python
I have values in a text column that are as follows:
000_100
100_200
...
1000_1100
1100_1200
I want it to read:
0000_0100
0100_0200
...
1000_1100
1100_1200
I want all values to have the ...
0
votes
1answer
44 views
if-else logic expression in field calculator
I want to calculate the value of a new field using an if-else condition with field calculator in modelbuilder. Want I want to do is as follows: if my new field is empty, then use the expression ...
1
vote
1answer
29 views
How to call Exelis ENVI tools with python and ArcGIS?
I am writing a script for geopocessing landsat data using ArcGIS 10.3. But ArcGIS doesn't have tools for landsat calibration (converting from DN to reflectance) and ENVI have this tool called ...
0
votes
0answers
11 views
GDAL2Tiles crash
GDAL2Tiles seems to crash after generating tiles and no google viewers are generated, but only openlayers.
This is the code I run:
os.system("gdal_translate -of VRT -a_srs EPSG:4326" + ...
0
votes
0answers
13 views
Radiometric Indices error
I have successfully included otbApplicaton in my python code. Tested the otb inclusion it is working fine. I am using the following code to generate NDVI output from the landsat image.
from sys ...
2
votes
3answers
72 views
Read HDF4 data using python
I am now working with VIIRS/NPP Active Fires by using python gdal. But I cannot read the data inside the files.
Filename = "NPP_AVAF_L2.A2012019.0600.P1_03110.2014057125956.hdf"
Here is some ...
0
votes
0answers
16 views
Problem calling qgis2leaf outside the QGIS
I am a computer programmer starting with PyqGis-Python, and I’d need to automatize the creation of a webmap using the plugin of qgis2leaf from a QGIS Project. I have reached to call “import ...
0
votes
1answer
26 views
Calculate area of a raster for an irregular polygon in PostGIS
I have a number of polygons with irregular shapes (i.e. non-rectangular) and want to calculate their areas after I have converted them to rasters.
Here are my steps:
Convert my geometry to a ...
2
votes
2answers
88 views
How to use `layer.getFeatures()` in a standalone script?
I am following the QGIS Cookbook and this post where it concerns reading attributes from layers. I would like to exploit this method and implement it into a standalone script.
Essentially, I want to ...
2
votes
1answer
37 views
use gdal python bindings from the QGIS folder in a custom script
I have QGIS installed (on Windows) and can import this line from the QGIS Python console:
from osgeo import gdal
When I try the import in a python file it doesn't work
Traceback (most recent call ...
1
vote
1answer
48 views
Python - Projecting different shapefiles in the same folder
I have a few shapefiles in one folder with different coordinate systems but would like to use one of them as a template dataset. Is there a way to use python to filter out the shapefiles already in ...
0
votes
2answers
44 views
QGIS from console: raster algebra
I'm newbie to programming in pyqgis. I need to perform a simple "GeoTiff * A" type of calculation(where A is a constant), but I am struggling to do so. I tried ...
1
vote
1answer
36 views
Calculate date field using date variable and time attribute in a feature class
I have a string variable (fileDateString) with the date in this format: 20150404
In my feature class there is a text field with time in twenty-four hour UTC format. There is also 2 leading spaces ...
0
votes
0answers
27 views
ST_MakePoint returns an error when using Python
I am trying to use ST_Point or ST_MakePoint to create points from a table of latitude and longitudes coordinates. However I am consistently getting an error even when trying the examples.
For example
...
0
votes
0answers
25 views
Search Address (Geocoding), Analyze intersecting underlying layer and return text results
What would the process be for going about accomplishing something like this via a website. Say I just wanted a website form where the user would input their address. Then beneath the scenes it would ...
0
votes
0answers
24 views
Making QGIS custom form modal?
I have created a custom form for entering attribute values for newly added features / editing attribute values for existing features of a shape file. I chose the ui file as "Edit UI" and a python file ...
1
vote
0answers
22 views
Closing QGIS custom form programmatically?
I have a custom form for entering and editing attribute values of a point shape file. I also added a button for deleting the actual feature. Deletion of the feature works fine and then I want to close ...
1
vote
1answer
43 views
How can I get features that satisfy a QgsExpression using PyQGIS?
I have two fields say "State" and "name" which would be get from the two comboboxes. After which, based on the current text in the combo box, I want to make QgsExpression and feature that satisfies ...
0
votes
1answer
42 views
How to access shapefile m-values with pyqgis?
Does anyone know how to access (read/write) m-values of a line-shapefile using pyqgis? I know how to do it with arcpy cursors ...
0
votes
0answers
29 views
How to raise exception from if statement in Python
This is a general python question, I would like to write a function that essentially states if data is available do this, if not raise an error, and a finally block which does something else.
In ...
0
votes
0answers
21 views
Is PyQt4 'drag and drop' functionality available in Qgis Plugins?
In Qgis 2.8, is it possible to use the PyQt4 drag and drop classes (dragEnterEvent, dropEvent) to interact with items from a qtreeview, in a Python Plugin?
Is it possible to hook into the ...
1
vote
1answer
54 views
QGIS custom Form - How to bind a value from a QComboBox?
I am trying to build a custom form for field data collection (bird species) with some python logic. The python code inserts values into a QComboBox:
At the beginning of the list it adds the twenty ...
1
vote
0answers
21 views
Where does GEOS Library gets installed QGis
Working on OS X 10.10, QGis 2.8
I want to install basemap. I installed QGis 2.8 which includes the GEOS and the PROJ4 library.
In order to install basemap properly, I need to pinpoint it to the ...
0
votes
3answers
47 views
How to change different projections of feature classes in geodatabase to one projection in new geodatabase?
I want to create a script that iterates through feature classes with different projections in a geodatabase and exports them into a new geodatabase, all with the same projections.
What I want is to ...
1
vote
1answer
29 views
Using 3rd party libraries on QGIS (Windows)
How can I use 3rd party libraries on QGIS plugins on Windows? I've developed a plugin that uses rasterio and numpy for a customer, but he's having problems installing rasterio and numpy.
Actually ...
4
votes
2answers
112 views
arcpy.da.SearchCursor ignores the where_clause parameter?
I'm trying to use arcpy.da.SearchCursor to go through records in a feature class stored in a SQL SDE database. I do so through a feature layer (created in arcpy) called "unit_lyr". When I run the ...
0
votes
0answers
31 views
Optimizing shapefile lookup time?
So, I have a ~1GB shapefile which is running circles around a ~5MB shapefile when it comes to feature look-up time (using python, with GDAL):
def check(name, lat, lon, attributeFilter:'SQL ...
2
votes
1answer
77 views
Select by location in Python
I have a polygon layer and a point layer (with coordinates for each point).
The polygon layer got created using the MMQGIS PlugIn (Hexagonal Polygons).
I want to select all the points inside each ...
0
votes
0answers
24 views
Help how to return values from multiple columns to dictionary [migrated]
can anyone help with how to call additional columns to my dict below please?
The example works fine for the return of one set of values (column) but I need to return values for 2 columns that are not ...
0
votes
0answers
57 views
Interpolation using GDAL
I am looking for some hints here. There is a shape file with point data of rainfall sampled at a regular grid, and there is a shape file with point data of soil attributes sampled at a regular grip ...
1
vote
4answers
65 views
How to remove period, comma, symbols using field calculator?
I want to delete . , # in attribute table using field calculator (VB Script or Python).
How can I remove these using this example address: N. First St., Unit #1 (I don't need city or state name)
I ...
0
votes
1answer
37 views
Iterate through all fields in attribute table and multiply by field
I have a table with a whole bunch of census variables (race, age, education, etc). I want to multiply all of these fields by a factor that I calculated. For example:
Field1 has values of 10,20,30,40
...
1
vote
0answers
34 views
QGIS 2.6 - installing exifread for photo2shape plugin
I've already seen Error loading plugin photo2shape even after installing exifread module and Error installing Photo2Shape QGIS 2.6 for Mac, and other forums, but can´t make it work.
First I installed ...
1
vote
2answers
109 views
How to populate attribute table with sequential numbers?
Using Python, how can we populate a field in a feature class automatically in increasing order? The user must be able to provide the start number. For example, say he wants to populate values from 51 ...
