Tagged Questions
Python is an open source interpreted programming language used in many GIS programs.
0
votes
1answer
12 views
Generating elevation 'database' from NED IMG data
I'm starting to work with the NED 1/3 and 1/9 arc-second data. I've been using gdal in Python and QGIS to do some basic conversions of the raw .IMG data from USGS. My goal is to get elevation data of ...
-1
votes
1answer
30 views
1
vote
1answer
26 views
Adding Vertical Reference in Python to ArcGIS feature dataset
I am creating a python script to generate a terrain. In the process I am creating two feature datasets. However, in order to successfully create this FD, i need both horizontal and vertical datums. I ...
0
votes
1answer
29 views
Can't get the where clause in Select layer by attribute working!
I am trying to develop a script that searches for a particular ID in a user selected field. To this end I have used the select layer by attributes tool to search for a derived number in a field ...
0
votes
0answers
10 views
Is it posible to save a dxf in memory
Following on from my question here, when I run the ExportToCAD tool
arcpy.ExportCAD_conversion(listOfLayers, formatRelease, location + fileFormat, "Ignore_Filenames_in_Tables", ...
0
votes
1answer
43 views
How to differentiate between land and sea in python?
I'm going to plot some positions of ships, and thus see which areas (out at sea) where there is no vessels, however, if I do this in an ordinary geographical area defined by a square, all the land ...
1
vote
0answers
27 views
Using gdal_merge to merge a large amount of files (in pairs)
I'm new to python and how it can be applied to gis.
I have a large amount of MODIS files to go through and I've already extracted, reprojected and converted to GTiff the bands that I need from each ...
1
vote
0answers
18 views
Setting PYTHONPATH for compiled QGIS version on Linux
I'm trying to set the PYTHONPATH in order to be able to load the qgis classes in a python console (not the QGIS Python one).
I followed some resources I've found (PYQGIS Cookbook, and others) but I ...
1
vote
0answers
20 views
How to register “events” for linear referencing in pyqgis?
Is there an easy solution for recording events for a line crossing borders of zones in a polygon layer? I need to implement this in python using QGIS, thus pyqgis. The image attached illustrates what ...
1
vote
1answer
45 views
How to select polygon features that intersect a line feature using pyqgis?
Is there an easy way to select all features in a polygon layer that intersect (overlap) a line feature? I need to implement this in python using QGIS, thus pyqgis. This code illustrates what I am ...
0
votes
1answer
24 views
Get Data for ArcPad extension and python
Is it possible to call the 'Get Data for ArcPad' extension using python? If so would someone be willing to share their code?
3
votes
3answers
51 views
How do I compare two features to test if they are identical?
What is the most efficient method for determining if two features (points, lines, or polygons) are geometrically identical? I'm not concerned about a square figure that contains eight vertices (four ...
1
vote
2answers
31 views
Adding new field and populating with shapefile name
I have a set of shapefiles that need a new field adding to them called "Policy_Ref". I then need to update this field with the shapefile name. However when I do, it uses the full title, including the ...
1
vote
1answer
30 views
What tool would be best for getting the max value out of Identical ID rows?
As the title may imply I want to keep the maximum value in field2 for several identical IDs in field1, the others are deleted for example this table:
Field1 Field2
14772 1
14772 4
14766 3
...
5
votes
0answers
91 views
+50
Python toolbox works in ArcToolbox and in Python console, but not in ArcCatalog
I have a set of Python tools in a Python toolbox (.pyt). They are broken into multiple files and modules and have been functioning correctly, but now I'm seeing inconsistent behavior on multiple ...
1
vote
0answers
11 views
Accessing elements Linestring and points from a DGN file and displaying both layers on QgsMapCanvas
I am using PyQGIS APIs to develop a standalone application which currently display's map data layers on QgsMapCanvas from .shp, .tif, .dgn files.
I am able to do it for .shp and .tif but not for .dgn
...
0
votes
0answers
14 views
Re-name using first letters of feature class name [on hold]
I have several feature classes and I want to rename them using the first letters of every word in their name (Proposed_Road_Network -> PRN) with python but I do not know how as I have very limited ...
0
votes
0answers
24 views
Implementation of script for bus waiting stops
I've tried to add waiting time in bus stops in several ways (elevation fields, sub-segments, etc), but nothing worked.
I'm now trying to use this script I've found in Internet:
if (SourceID of ...
2
votes
3answers
106 views
Using .len() in IF THEN statement in ArcMap field calculator
I have a string field with values of varying lengths (1-4). I need each value to have a length of 5 characters by adding zeros to the value until the length equals 5. For example:
123
needs to ...
3
votes
1answer
40 views
add text value to attributes
this is a novice question
I have an attribute field that's missing a piece of information, i'd like to amend the attribute field like below:
This is the current attribute field:
"V:\Building & ...
2
votes
1answer
26 views
Landsat Surface Reflectancce product Python packages
I have to work with numerous Landsat surface reflectance product that I downloaded from http://landsat.usgs.gov/CDR_LSR.php. The product comes with a QA data with information on clouds and shadows ...
0
votes
2answers
42 views
Applying symbology to a layer with python, How to only have symbology in TOC that the sub layer has
i am trying to apply a symbology to multiply layers that i have created from one feature class.
The original feature class is used to create several sub layers see
layer loop
this involves using ...
3
votes
0answers
27 views
QGIS/Python script to generate random points many times
Good day. Can anybody provide a simple code to be run in the Python Console of QGIS (I am using 1.8 Lisboa) to generate X number of random points (say e.g. 5000) over a certain global shape of ...
1
vote
0answers
37 views
If then statement in model builder
I have a model that adds several fields, two which are manual inputs (County Name and User). I am manipulating several parcel layers (approx 90 counties).
In my model, one field takes the state and ...
2
votes
2answers
30 views
Map canvas overlay layers QGIS
I built my own map canvas inside a plugin in QGIS and I want to add two layers (one by one) in order to overlay the two.
I have this code:
fileCI = "....\plugins\teste\test.shp"
fileInfo = ...
1
vote
2answers
44 views
ignore Null Values when iterating through fields with python
So far I have a code which iterates through Fefature Classes and ignores all fields of type String, Geometry and OID.
I now try to add some lines which tell python to ignore all NULL values when ...
1
vote
0answers
27 views
import qgis geoprocessing tools in python os x 10.9.5
I'd like to use the python bindings from qgis, but in a standalone project.
I need the geoprocessing tools for vectors.
I updated QGIS (Wien - 2.8), python (3.4.3), etc.
However, it always ends with ...
1
vote
0answers
41 views
QGIS python originalName() does not return actual original layer name
I am writing a Python QGIS Plugin, using QGIS version 2.6 as the basis for development. When loading data into the canvas programmatically, I am trying to maintain the spatialite table name as the ...
1
vote
1answer
38 views
What resampling method is used in gdal_merge?
I am using the gdal_merge python script to merge rasters that have slightly different, though similar, input resolutions. The documentation advertises that it can handle different resolutions, and in ...
1
vote
1answer
33 views
Labeling layers with Python in QGIS. LinePlacementFlags
How could I set LinePlacementFlags with Python in QGIS?
My code is something like:
palyr = QgsPalLayerSettings()
palyr.readFromLayer(layer)
palyr.enabled = True
palyr.fieldName = "attribute"
Then ...
1
vote
0answers
41 views
How to automatically generate pour points along stream network?
The following screenshot shows the results of a water flow analysis where I identified stream order via the Strahler method in ArcGIS. Now I need to generate watersheds for 2nd order streams and ...
0
votes
1answer
56 views
arcpy.da UpdateCursor where_clause
I am trying to get a where_clause working on a UpdateCursor (arcpy.da). I can get it to work fine with a SearchCursor, but for some reason the same clause throws a RuntimeError: General function ...
2
votes
0answers
42 views
Using Python to iterate through directory to create event layer and perform kernel Density for each file?
I am new to Python for ArcGIS, but have been using ArcGIS a while.
I have a large directory of tables with point data. For each file of each folder I want to create a kernel density layer.
I have ...
1
vote
0answers
21 views
Execute GRASS command within qgis phython console
We try to calculate catchments with the r.water.outlet function from python console. To do so we use the following code:
import processing
rlayer = QgsRasterLayer("/my/path/DrainageDirection.tif", ...
0
votes
0answers
29 views
If/then python for classifying existing field values to a new field
I'd like to have a tool or quick python script to classify an existing number field to a new text field. For example I have a roads layer that has a type identifier as a coded number and I would like ...
0
votes
0answers
41 views
Advice for Python with GIS [duplicate]
How you can I install different packages in python and not have problem with the arcpy module in ArcGIS? I want to be able to run Python as standalone, do other python programming as well as GIS ...
0
votes
0answers
48 views
Configuring Python to avoid conflict with ArcGIS for Desktop (ArcPy)?
I am trying to find the best way to configure a new version of python in my computer (windows) so that I do not have any problem with the python version that I have with ArcGIS. Is there anyway to ...
1
vote
0answers
29 views
Spatial join with multiple intersecting features
I have a polygon dataset representing pavement areas broken up by year of construction and a roads centerline dataset that contains values for remaining service life (RSL). I want to spatially join ...
1
vote
1answer
34 views
Field calculater in Python console from QGIS
I have some doubts in syntax of processing.runalg(qgis:fieldcalculator) in python console of QGIS. I want to create a new field in a shapefile and calculate this formula: [D_PATRICIA]*1000. ...
0
votes
1answer
47 views
ArcGIS 10.0 Python script not working with ArcGIS 10.2.1. Looping through SelectLayerByLocations
Last year I got assistance from StackExchange to write a Python script for ArcGIS 10.0 which loops through SelectLayerByLocation with buffer until it returns no new rows. Then it uses the selection ...
0
votes
1answer
50 views
cannot concatenate str and list objects
I'm trying to rename a group of rasters to "I1986_" + [The 1st 3 letters of the raster]. For example, if a raster is named "Raster1", the output would be "I1986_Ras".
I've tried including str() ...
0
votes
2answers
34 views
working with geojson and vincent on python
I want to import a geojson file into python so I can map it with a visualization package vincent and merge with other data in a pandas data frame.
To be specific, the said geojson file is: ...
1
vote
1answer
37 views
How to replace field name with a variable in exported whereclause?
In the select by attribute how do I replace "AADT", with a predefined string variable?
I don't understand the pattern in "\"AADT\">=" , can you please explain why is it that way when exported from ...
0
votes
1answer
50 views
Python Script to Select records based on user input
I am running Arc 10.3 in a versioned environment. I am attempting to write a simple code that will select service records coming from Oracle CRM to a separate feature class containing only records ...
2
votes
1answer
74 views
How to create a plugin GUI for QGIS 2.8.2?
I create a pluging with the pluging builder in Qgis 2.8.2. I went to the folder of my pluging : C:\OSGeo4W64\apps\qgis\python\plugins\yu in order to visualize al the files that the pluging builder ...
1
vote
1answer
31 views
How to search for fields in a GDB and add them if they don´t exist with arcpy?
I have a list of files that need to be present in my featureclasses - myFields[].
I need to add these fields if they are not present in my FeatureClasses.
import arcpy
myField="Field01"
myFields = ...
0
votes
0answers
18 views
Python Error when I start Qgis
Thank you for the comment for this post:
QGIS 2.8 starts with an error and I am not able to run Python console
I have run yum search yum search qtwebkit and I got it that is installed.
...
1
vote
1answer
22 views
Parsing path and calculate value in model builder
I am experiencing an issue with the model only tool calculate value. I am attempting to use the parse path and calculate value model only tools to force a feature dataset into the create topology ...
2
votes
1answer
74 views
How to use %i%“.csv” in arcpy to name an output csv file?
I am using arcpy to describe datasets and output the results into a csv file. I am doing this via a script in arctoolbox and would like to save the file in the same folder as the file being analysed. ...
1
vote
2answers
74 views
Using Google API within Python and applying to ArcMap?
I am currently doing a practical project at university (MSc in GIS).
I have to develop a python script and the functionality of this script has been left very open other than we have to use Python ...
