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1500 questions
21
votes
4 answers

gdal_calc raster calculator syntax for logical operators and other functions

In documentation for gdal_calc it is stated Command line raster calculator with numpy syntax. Later on there are few examples where in one of them: gdal_calc.py -A input.tif --outfile=result.tif --calc="A*(A>0)" --NoDataValue=0 - means set values…
Miro
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21
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4 answers

Where do I find the ogr2ogr command for Mac OS X Lion?

I am looking for the equivalent of FWTools for Mac OS X, Lion. Is there anything I can easily install and get that command?
CLJ
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21
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3 answers

Finding distance between two coordinates in ellipsoid?

I have two sets of latitude and longitude. How do I find the distance between the two locations if I assume the earth is a perfect ellipsoid (with an eccentricity of 0.0167)?
Jon Bringhurst
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21
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1 answer

Import a shapefile to postgis with ogr2ogr gives: Unable to open datasource

I want to use ogr2ogr in order to import a shapefile in a postgis database. I have successfully installed ogr2ogr and I run from the pgsql the following command: ogr2ogr -f "PostgreSQL" PG:"host=localhost user=user_1 password=***** dbname=imports"…
user1919
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21
votes
1 answer

Exporting map with transparent background in QGIS

I have gone into Composer and specified the page background to be transparent. It still comes out white. Is there a solution?
Geoff Fox
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21
votes
2 answers

Loading vector tile layer in Leaflet map?

I need to load a vector tile layer in a Leaflet map. The vector tile is the vector tile layer about Mapillary sequences (look at https://a.mapillary.com/#vector-tiles ...), and the tile URL pattern…
Cesare
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21
votes
7 answers

Joining data from Excel to attribute table in QGIS without creating duplicates?

I have an attribute table with two empty fields in QGIS. I want to import an excel database to fill my empty fields in QGIS. My excel file matches the columns in my QGIS attribute table. I am able to properly join my excel (.CSV) to my…
Laurent Robitaille-Lainesse
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21
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2 answers

Seeking free Shapefile editor

I want to create and edit shapefiles for my application. Is there a free shapefile editor?
AliRezza
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21
votes
4 answers

geopandas spatial join extremely slow

I am using the code below to find a country (and sometimes state) for millions of GPS points. The code currently takes about one second per point, which is incredibly slow. The shapefile is 6 MB. I read that geopandas uses rtrees for spatial joins,…
Alexis Eggermont
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21
votes
7 answers

Retrieving start and end points for each line in line shapefile in ArcGIS Desktop or QGIS

I have a vector(polyline) shapefile and I need to retrieve each line´s start and end points(nodes) and create a shapefile with these points. Then I need to add to the polyline´s attribute table the start and end point for each line based in the…
user51651
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21
votes
2 answers

Finding the Center Line from a set of 3D Points

I have a set of 3D points. They follow a curved pattern with a rather constant diameter as shown below. What would be the algorithm to trace the approximate center line of these points?
vinayan
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21
votes
4 answers

Creating simple front-end for PostGIS database

My organisation collects a lot of environmental monitoring data (stream flow, water chemistry etc.) most of which is currently stored in Excel. I’d like to get everything into a database – probably PostGIS – but I need the data to be accessible to…
JamesS
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21
votes
6 answers

How to parse EXIF GPS information to lat,lng decimal numbers

"EXIF_GPSAltitude": "(220.279)", "EXIF_GPSLatitude": "(55) (40.711) (0)", "EXIF_GPSLatitudeRef": "N", "EXIF_GPSLongitude": "(8) (30.2282) (0)", How should i understand the above example as degree, min, sec? Some EXIF data that I extracted has…
Poul K. Sørensen
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21
votes
6 answers

Defining layer CRS and avoiding CRS dialog in PyQGIS?

There is an existing Shapefile, which I want to add. At the moment my code looks like: self.iface.addVectorLayer(self.shpFilePath, "Track", "ogr") It works fine, but i want to define the crs within the code. Is it possible? I found some similar…
Hinne123
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21
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3 answers

What are the differences between spatial databases?

What is the difference between Oracle Spatial, PostGIS, SQLServer2008, SpatiaLite, and MySQL in terms of their spatial support. Are there specific use cases where each shines. What might you want to avoid with any of these databases.
TheSteve0
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