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1500 questions
30
votes
8 answers
Getting list of distinct values from shapefile field using QGIS
I have a shapefile whose features I can filter by specifying a where clause in the query dialogue. F.x. I have a field named "city_name" and by stating "city_name" = 'London' in the where clause only London is displayed. What I would like to do now…
Raffael
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30
votes
7 answers
Why don't they use cell towers like GPS satellites?
If my understanding is correct, a GPS satellite produces a pretty simple signal which is basically composed of its location and its time. Given 4 of these signals, then one can uniquely solve for the X,Y,Z position (and as a by product, time) of…
John Berryman
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30
votes
3 answers
Loading .osm.pbf file in QGIS
.osm.pbf it`s the extension for OpenStreetMap extract that I get from a site that takes daily extracts from OSM: http://download.geofabrik.de/
How to import these files in QGIS (on Linux or Window)?
Badita Florin
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30
votes
6 answers
Using ogr2ogr to convert GML to shapefile in Python?
I am trying to convert a GML to an ESRI shapefile using ogr2ogr utility in a python script.
I have successfully installed the GDAL/OGR package via osgeo but I am now struggling to find/understand any details on the syntax for using ogr2ogr in…
Matt
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30
votes
6 answers
Calculating terrain Curvature in QGIS
I have an elevation raster and I would like to get some basic terrain variables, such as slope, ruggedness, aspect or curvature.
The problem is that I don't seem to have the possibility to calculate curvature with the terrain analyst:
Can anyone…
Damien
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30
votes
2 answers
Calculating areal distortion outside UTM zone?
One of my colleagues is working with data that is spread across two UTM zone. The majority of the data is in one zone, with a few outliers in another zone. He would like to know what the area distortion of those outliers would be if they were in the…
kenbuja
- 5,700
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30
votes
6 answers
Ways to Speed Up Python Scripts Running As ArcGIS Tools
This is a pretty general question. I just wondering what tips and tricks GIS programmers have used to speed up arcpy scripts that you import into the toolbox and run.
I work most everyday writing little scripts to help non-GIS users at my office…
Cody Brown
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30
votes
3 answers
Opening GeoJSON file with mixed geometries in QGIS?
If I have a GEOJson file, for example a file named test.js with inside the following:
{ "type": "FeatureCollection",
"features": [
{ "type": "Feature",
"geometry": {"type": "Point", "coordinates": [102.0, 0.5]},
"properties": {"prop0":…
caneta
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30
votes
5 answers
Drawing polyline in Leaflet?
This is my coding I used in Leaflet:
var pointA = new L.LatLng(28.635308, 77.22496);
var pointB = new L.LatLng(28.984461, 77.70641);
var pointList = [pointA, pointB];
var firstpolyline = new L.Polyline(pointList {
color: 'red',
…
againstflow
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30
votes
9 answers
Value of a Python programming course
I am considering upping my programming skills by taking a python geoprocessing course through ESRI. Before I part with the hefty registration fee, I would like to get your opinion on the value of 24 hrs of instructor led python programming. I am…
Aaron
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30
votes
3 answers
Finding all neighbors using GeoPandas
I am wondering whether it is possible to identify all neighbors to each polygon using only Python (with e.g. GeoPandas) in the same way as with Python in QGIS (Find neighbors polygon).
user119945
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- 3
30
votes
5 answers
Coloring thousands of polygons so each is distinct from its neighbors?
I am using ArcGIS 10, and I have layers of the 2010 Census blocks, block groups, and tracts. There are thousands of polygons in these layers.
I want to color them so that each is distinct from its neighbors, but all I can figure out is how to…
Carl Raymond
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- 5
30
votes
5 answers
Is there an online catalog for declassified Soviet Union Spy Satellite images (Zenit-4, Resurs-F1, Okean)?
I'm a glaciologist user of declassified US Spy satellite images (Corona Key Hole satelites, Hexagon, etc.), that provide an extraordinary record of glacier extent at resolutions equivalent to about 4 meters per pixel (see this amazing example).…
Camilo Rada
- 1,219
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30
votes
1 answer
Cannot get plot() in geopandas to produce a map of the GeoDataFrame
I have installed all the necessary and optional modules for geopandas (with the exception of rtree) as listed at http://geopandas.org/install.html
I am following the tutorials from this site and also from a couple of other bloggers such as…
Clubdebambos
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30
votes
5 answers
OpenSource Remote Sensing Tools for Classifying Roofs
with envi image processing and classification tools, you can get roofs from images with some spectral value and then you can convert it some vector data for your app.
in python with OpenCV which have devoloped by Intel (has lots of Object Detection…
urcm
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