Questions tagged [geoprocessing]
Geoprocessing is a GIS operation used to manipulate GIS data. If you are performing geoprocessing using ArcGIS then the tag Geoprocessing-framework is specific to that software and should be used instead.
192
questions
5
votes
2
answers
13k
views
What are units for calculated area in QGIS?
I have a shapefile of counties in the US, and I would like to calculate the area of each polygon so that I can run a population density calculation. However, I am having trouble calculating the areas. ...
5
votes
1
answer
5k
views
Performing Geoprocessing SQL Queries in QGIS from a PostGIS Database
This may be a dumb question, but is there way to run a PostGIS geoprocessing SQL query in QGIS? Specifically, I am thinking of running SQLs such as ST_Union, ST_Split etc etc.
I have tried the ...
5
votes
2
answers
9k
views
Fixing Script Error Invalid Pointer from ArcGIS Geoprocessing Tools?
I am just learning ArcGIS 10.2 and it was working well until I tried to use the Export to a Geodatabase (single) option for a dbs table I made. Since then, it seems I now get the same Script Error for ...
4
votes
2
answers
7k
views
Event layer to feature class - fastest method?
There are three methods to convert the output of a Make XY Event Layer to a Feature Class:
Copy Features
Feature to Point
Feature Class to Feature Class
Which one is the fastest method? I need to ...
4
votes
2
answers
6k
views
Create a single connected polygon from multiple polygons
I am trying to create a single continuous (neighborhood) polygon from many tax block parcels. The Multipart to Singlepart GP tool does not accomplish the task since I need the polygon to be complete; ...
4
votes
2
answers
6k
views
Calculate area in square meters from degrees?
I have a polygon shapefile in geographic coordinate system, I would like to calculate area in square meters in QGIS using Python.
Is there any formula or equation to do this?
4
votes
2
answers
6k
views
How to convert GeoTIFF to grayscale and add gaussian blur?
I have a giant GeoTIFF I'd like to convert to grayscale and add a gaussian blur to. As far as I know, GDAL can strip two of the three color bands and call it grayscale, which might work, but is there ...
4
votes
1
answer
1k
views
Raster Calculator dynamic map algebra expression
Is it possible to dynamically construct a Map Algebra expression that is dependent on the output of another tool, either using model builder or arcpy? For example, say I have a model that performs a ...
4
votes
2
answers
613
views
Slow performing ArcGIS Near tool returns -1?
We are running an ArcGIS 10.0 geoprocessing script written in Python that (as part of many steps above & below) runs the Near tool.
Both the input and output datasets (shapefiles & personal ...
4
votes
2
answers
220
views
Issue with QGIS 2.10.1 Clip and Intersect Tools
Having an issue in QGIS 2.10 -- clip and intersect don't seem to be working correctly. I am trying to show zipcode by a legislative district in Florida. When I clip the zipcode shapefile by the ...
4
votes
1
answer
2k
views
Reading data from raster layer obtained via WMS in QGIS
I need to use some geological data from the WMS service http://mapas.igme.es/gis/services/oneGeology/IGME_EN_Geology/MapServer/WMSServer using QGIS. I've connected to the service and I can see the ...
4
votes
2
answers
2k
views
Getting "Failed to open tool" message when trying to run geoprocessing tool from C# code
I've been experimenting with the Military Aspects of Terrain Template, which has a toolbox associated with it. I've been using the following WPF Runtime code, which should open a tool in the ...
3
votes
4
answers
2k
views
Redistribute linestring vertices to specified distance
I use a groundwater model program called GMS, and it has a very useful function "Redistribute vertices" (more info). I use this function all the time to both simplify and provide regular spacings ...
3
votes
3
answers
3k
views
How to batch clip to single-part shapefile using ArcGIS 9.3 and Python 2.5?
How do I clip a shapefile to a single-part shapefile using ArcGIS 9.3.1 and Python 2.5?
Example: I have a set of lines (lines.shp) I am trying to clip to each record in a shapefile called Grids.shp
In ...
3
votes
2
answers
285
views
Polygon Neighbors not found in Proximity Toolset of ArcGIS Desktop 10.0?
I cannot find the Polygon Neighbors tool. I have searched for it as I usually do and I have also browsed the proximity toolset but it is not there. The other Tools, e.g. Buffer and Near are there and ...
3
votes
2
answers
2k
views
Set a split policy/rule on a field without domain in ArcMap
Can you define a split policy or split rule on a field without a domain? When a domain is involved, you can set the default value of the field and chose a rule for when a feature is split or merged.
...
3
votes
2
answers
1k
views
Problems Integrating Sub-Model into Master Model
I am attempting to integrate a iterative model into a master model to merge all of the outputs of the iterative model into one feature class. However, when I attempt to set the output of the sub-model ...
2
votes
1
answer
369
views
ArcGIS Geoprocessing "None Type" Second time
I am trying to publish an ArcGIS geoprocessing service in 10.2 I have a script setup that will run multiple times through Pycharm, but when I run it in ArcGIS it will run once and return this error:
...
2
votes
2
answers
1k
views
Clip for each feature
I want to clip a polyline feature class by a polygon feature class (buffers created from points). Several polygons overlap, so I want to get each polygon feature clipped with each polyline feature.
...
2
votes
1
answer
2k
views
CSV list as input parameter in QGIS 3.0 Processing Modeler
I have CSV list with XY coordinates (company and its competitors) which I want to input into simple QGIS Processing model. From this list the model creates and styles two spatial layers.
Everything ...
2
votes
1
answer
1k
views
How to control which Fields are exported in ArcObjects? (via Field Mapping)
In ArcMap 10.x, if you use the Export Data command on a layer that has hidden/disabled fields, those fields will not be present in the created feature class/table. My question is simple: how do you ...
2
votes
1
answer
1k
views
Large Dataset Buffer Help
Using ArcGIS 10.1. I have a large polygon feature class (130,000 records). I need to do an inside/outside buffer (+5 then -5 to fill in some gaps)... the process takes so long, I'm looking for a way ...
2
votes
3
answers
1k
views
Polyline selection of features with angle turns up to a specified angle
I'm looking for an automated way to select line features that have specified angle between vertexes. That in order to check water mains layer -steel pipes can have only 45 or 90 degrees turns and I ...
1
vote
1
answer
466
views
ArcGIS Toolbox functions missing all parameters?
I recently installed ArcGIS 10.3.1 and now all the toolbox functions (that I have tried) open, but they have no parameter fields. For example, the "Add Field" tool comes up with the standard toolox ...
1
vote
1
answer
1k
views
Testing point in polygon overlay performance of Intersect, Spatial Join and Near in ArcGIS for Desktop?
In answers and comments to Select points within a polygon and update attributes I think it is being suggested that Spatial Join (Analysis) and/or Near (Analysis) may be faster than Intersect (Analysis)...
1
vote
1
answer
2k
views
Can variable be set to reference in_memory workspace object in ArcPy?
This is an offshoot question related to a question I posted earlier. I have the following arcpy code that inputs a Python list of polygon geometry objects to the Union_analysis tool, which then ...
1
vote
1
answer
429
views
Controlling XY Resolution on file geodatabase feature class output from Append?
This question arises from research into Appending polygon feature classes with already repaired geometry => WARNING 000442: self intersections from Check Geometry?
Before running the code snippet ...
24
votes
8
answers
2k
views
Is there an architecture for distributed geoprocessing?
Suppose I have 50 computers on my LAN. Each computer has a geodatabase for all parcel polygons in a particular state in the US.
I'd like to write a geoprocessing task that finds all parcels valued ...
16
votes
6
answers
1k
views
PostGIS: Assign ID of point in layer A to closest point in Layer B
This should have been an obvious precursor (that I didn't ask) to my other question:
How to create spider diagrams (hub lines) in PostGIS?
If I do not know the relationship between a point in layer A ...
16
votes
4
answers
912
views
How to handle TIME in GIS?
Is there any way or any idea on how to handle Time attribute in GIS? For example, which are the ways to specify that an object is at a place at a given time interval and them it is in another place ...
15
votes
2
answers
4k
views
How to import esri Personal Geodatabase (.mdb) to PostGIS on Linux
We have esri Personal Geodatabases that we need to import into PostGIS.
Ultimately, we'd like to allow people to upload an MDB on a web server, and have it import the layers into PostGIS.
On ...
15
votes
1
answer
19k
views
Is Clip (Data management) or Extract By Mask (Spatial Analyst) more efficient?
I'm trying to clip down an Orthophoto to a county boundary. I've been using the Extract By Mask Tool, but this process has been running for about 12 hours! It's gone through 2 cycles already, so I'm ...
13
votes
1
answer
6k
views
How to achieve equivalent to Dissolve from ArcGIS for Desktop using ST_Union?
I am trying to achieve an equivalent to the Dissolve tool from ArcGIS for Desktop using ST_Union from PostGIS but it seems I am not getting expected result.
I have one table which has certain ...
12
votes
3
answers
739
views
File organization for sharing ArcGIS python code
What is the best organizational structure for sharing ArcGIS python code and geoprocessing tools? Or even, are sharing code and sharing tools separate questions?
Esri has a Methods for distributing ...
12
votes
4
answers
684
views
Mirror of Michigan State University's Python geoprocessing course materials
Been learning geoprocessing with Python using MSU's GEOG 825 ( python geoprocessing ) course. Unfortunately the link is dead now. I know this is a long shot but does anybody have a copy of the ...
11
votes
2
answers
11k
views
What is "Simplify tolerance" in QGIS's Simplify geometries tool?
I am trying to use QGIS 2.8 to simplify vector geometries. But I do not understand the significance of the Simplify tolerance value in the Simplify geometries tool.
The documentation does not ...
11
votes
3
answers
20k
views
arcpy.MakeFeatureLayer in-memory layer still exists when subsequent step fails during testing
When I used arcgisscripting to create in-memory output layer with gp.makefeaturelayer, I would put it in a try/except block and delete the gp object in the except piece when the makefeaturelayer would ...
10
votes
3
answers
16k
views
Log file for ArcGIS geoprocessing?
Whenever I run a geoprocess overnight, it seems my computer reboots. Does ArcGIS save some log file information? Where does it save it?
For example, when I run a large dataset or image process I need ...
9
votes
1
answer
1k
views
PostGIS "Overlay" Style Union, not "Dissolve" Style [duplicate]
I'm trying to use PostGIS to do a 'union' of polygons. When I Googled "PostGIS Union", I found the ST_Union function, which performs what I would call a 'dissolve,' not a Union. What I actually want ...
9
votes
8
answers
8k
views
Maximizing the use of CPU
My script is intersecting lines with polygons. It's a long process since there are more than 3000 lines and more than 500000 polygons. I executed from PyScripter:
# Import
import arcpy
import time
# ...
9
votes
3
answers
3k
views
How to determine on which side of a line a polygon feature falls?
I have parcel data intersecting line data. In the parcel data there are some parcels that don't intersect the line. How could I programmatically figure out if the non-intersecting parcel is on the ...
9
votes
3
answers
885
views
Making county-level shapefile from set of points at 30 x30 km spacing using ArcGIS for Desktop?
I have a data set in csv form, like:
latitude, longitude, value
-45, 45, 10
....
I would like to calculate county level means from these data, using either ArcGIS or R+grass.
I have the ArcGIS USA ...
8
votes
1
answer
2k
views
Where is this raster offset being introduced in the QGIS processing toolbox?
I'm using the (awesome!) processing toolbox in QGIS 2.0 to reclassify some NoData values in a raster from -9999 to 0, but at some point in the process there's an offset of about 0.2 degrees being ...
8
votes
3
answers
6k
views
Sort a feature table by geographic location
Here's in interesting challenge: I need to embed a table in a map layout so that the records in the table are sorted according to their geographic position on the ground. For example, in a north-to-...
8
votes
2
answers
5k
views
Using multipolygon or polygon features for large intersect operations?
I have two large layers that I want to do intersect operations. One is municipalities and the other is landuse. Right now, the landuse layer is of MultiPolygon type that is, for the entire state, I ...
7
votes
1
answer
1k
views
Is there a way to get the percentage of different landuse types upstream of a given point?
I'm a fairly novice GIS user and know just enough to get in trouble in a lot of cases. I am trying to look at the connection between several measured parameters at a few hundred stations along ...
7
votes
5
answers
764
views
Is there a way to Query what's "NOT THERE"?
If you have land tenure mapping, and you're only interested in the areas for which there are no polygons in a region, is there a way to query these areas out and create a shapefile from them.
A ...
7
votes
4
answers
7k
views
R Raster package: write NetCDF with time dimension
I am writing a rasterbrick with multiple layers to a netcdf file using the raster package in R:
writeRaster(gridfile, "Data", "CDF", overwrite=TRUE,
varname="Data",varunit="mm.d-1",longname="...
6
votes
2
answers
9k
views
Looking for Python module to do lat lon calculations
I'm looking for a Python module that can provide some / all of the following services using latitude/longitude to define points:
Distance between two points
Point in polygon
Distance along a multi-...
6
votes
1
answer
4k
views
How to clip a single layer of overlapping polygons in QGIS
I have a single layer of polygons. Some of the polygons overlap.
I wish to make a new layer of just the parts of the polygons that overlap.
What is the best way to do this in QGIS seeing it's all in ...