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4 answers

Difference between node and vertex in GIS?

In graph theory the term of node and vertex are equivalent, but sometimes in the GIS world the nodes and vertex are mentioned in the same context. I was wondering what the difference is? Node: can be a start and an end node from a link (edge)
user12282
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2 answers

Why do we use the terms “longitude” and “latitude” for a spherical body?

To specify a geographic coordinate we use the terms “longitude” and “latitude”. Far as I know, these terms derive from the Latin latitudo (= breadth) and longitudo (= length). In German we use the terms “Breite” (=english “breadth”) and “Länge“ (=…
Jens
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32
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4 answers

Disable leaflet interaction temporary

How can I temporary disable zoming/draging the Mapview in Leaflet.js Tried so many ways but without any luck. It's important to make it temporary and I also need the option to enable again.
Bernhard
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32
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3 answers

Trilateration algorithm for n amount of points

I need to find algorithm that can calculate centroid A (aka gravity center, geometric center, center of mass) from the figure where circles T1,T2,T3,T4,T5,..,Tn intersect AND length of line R from centroid to farthest corner of mentioned figure…
Kārlis Baumanis
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32
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13 answers

Extracting raster values at points using Open Source GIS?

How can I extract values from a raster by points? I prefer not in Arcgis. I prefer in Qgis or Mapwindow or other open source gis.
Vassilis
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32
votes
12 answers

Converting KML to shapefile without losing attributes using QGIS

I have a KML file with hundreds of points. To each point there is information, such as Name, Power, Age (it's a map of hydroenergy powerplants). If I import that KML file to QGIS, this information is lost. Is there a way I can keep this…
Felix
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32
votes
2 answers

Streamlining Python Code for Big Data

I have Python code which is designed to take point shapefiles through the following workflow: Merge points Integrate points, such that any points within 1 m of each other become one point Create Feature layer, where points with z < 10 are…
Aaron
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32
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6 answers

Creating Centrelines from Road Polygons/Casings using ArcGIS Desktop?

I want to create center lines from road polygons. Are there any automated tools in ArcGIS for Desktop to do this? I am including a Screenshot of my vector file below.
Binoy
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32
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3 answers

Сreating polygon from coordinates in GeoPandas

How to create a polygon from coordinates in GeoPandas with Python?
Davma
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32
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4 answers

Filter by bounding box in GeoPandas

I have a GeoPandas DataFrame in EPSG:4326 and I'd make a new DataFrame consisting of all the rows that fall within a certain bounding box. First I get the bounding box that I care about (which is actually the bounding box of another…
Richard
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32
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2 answers

What is the Difference between Geometric and Geographic columns?

I am a beginner in GIS and Learning PostGIS. I came across this two terms Geom and Geog, Could anyone explain in brief. What is the best to use with map data and Do all functions support both Geom and geog.
azzaxp
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32
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3 answers

Understanding "Join Attributes by Location" in QGIS

I wonder if there is somewhere an explanation for the parameters that can be set when running the Algorithm "Join Attributes by Location" in QGIS 2.18. I had a look here: Documentation QGIS Testing | Join attributes by location Documentation for…
four-eyes
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32
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3 answers

Copy a geometry from one feature to another without attributes?

With QGIS it's easy to add a new part to an existing feature/geometry but I can't see how to copy/paste this part from another existing feature/geometry. Is it possible?
nippo
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32
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2 answers

Best-practices for databases and APIs with geographic data spanning the antimeridian

What is the best-practice for storing geographic features (lines, polygons and their multipart equivalents) when these features span the antimeridian (±180° longitude), and need to be sent to and recieved from client web applications as GeoJSON? I…
alphabetasoup
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32
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6 answers

"Oddities" in the Shapefile technical specification

I've been writing a shapefile parsing library, and have encountered a couple of design decisions in the specification that I don't immediately understand. I'm hoping there's a wizened old ESRI developer around here who can tell me why these things…
canisrufus
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