Tagged Questions
2
votes
1answer
84 views
Intersection of convex polygons on a spherical surface
There are a number of algorithms available for the intersection of two convex polygons, but I am interested in an algorithm to find the intersection of two convex polygons on the surface of a sphere, ...
4
votes
1answer
98 views
Method for finding points that cover an extent
If I have a geographic extent, is there any way to find all of the center points of all of the 5km circles that would be needed to cover the entire extent?
I'm working with an API that will return ...
5
votes
1answer
203 views
Python: find a method to calculate the “inner centroid” (also known as labelPoint in arcmap) of a polygon
i am looking for a method to compute the X,Y coordinate of a inner point (also known as labelPoint in arcmap) of a (irregular) polygon. I am try to find a solution without the use of ArcGIS module
...
9
votes
1answer
256 views
How to visualize azimuthal data with uncertainties?
I am trying to make a figure showing azimuthal data with a different range of uncertainties at each point. This oldschool figure from a 1991 paper captures the "bowtie plot" idea that I'm aiming for:
...
4
votes
3answers
2k views
Splitting lines automatically at specific distances?
I have a set of polylines I need to split at varying distances from their starting points. In general I'm looking for a something similar to the SPLIT function within the editor tool. There it is ...
3
votes
1answer
213 views
How Can I Calculate Time from Coordinate?
For my application I am searching for an API or an algorithm for clicking point time and time zone. I dont know how I can do this but after getting time I want to calculate giving coordinate sun ...
6
votes
1answer
155 views
Optimize GEOSGeometry's spatial operations by avoiding thread-safety checks
A ranking algorithm I'm developing for a Django webapp requires performing spatial operations (within, intersections, sym_difference, etc.) using a query against large number of geometry objects.
...
3
votes
2answers
140 views
How to bring polygons closer to a point?
I have some scattered polygons with a lot of space between them.
I want to make a thematic map but all that white space doesn't look very good, so I want to bring the polygons closer to the center of ...
8
votes
3answers
3k views
Bilinear interpolation of point data on a raster in Python?
I have a raster that I'd like to do some point interpolations with. Here is where I'm at:
from osgeo import gdal
from numpy import array
# Read raster
source = gdal.Open('my_raster.tif')
nx, ny = ...
10
votes
4answers
2k views
Clustering Trajectories (GPS data of (x,y) points) and Mining the data
I've got 2 questions on analyzing a GPS dataset.
1) Extracting trajectories I have a huge database of recorded GPS coordinates of the form (latitude, longitude, date-time). According to date-time ...
16
votes
1answer
3k views
How to divide a polygon into specific sizes using ArcGIS?
I have several thousand irregularly shaped polygons in a shapefile. I want to be able to split each polygon into three areas, and to specify what the size of those areas (they sum to the previous ...
