A mathematical procedure used to solve problems with a series of steps. Algorithms are usually encoded as a sequence of computer commands.

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2
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1answer
35 views

Segment matching on a polyline

I have about 1000+ running routes which I can load into memory as polylines using latitude and longitude data captured from a running watch. From these polylines I would like to be able to identify ...
2
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1answer
31 views

Calculating a point Lat/Lon from another Lat/Lon point angle

I need help for a solution of this problem to make an algorithm: : I have a point O center of a circle of radius r, on this circle there is two point P1 and P2. I know latitude and longitude of ...
2
votes
1answer
55 views

netCDF4 Python climate algorithm

I have been working in Python with the Acaconda Python distribution to create code that accomplishes the following algorithm: I have multiple variable netCDF4 files [NCEP Reanalysis tmax(K), tmin(K), ...
4
votes
0answers
142 views

Find and destroy duplicate OSM multipolygon/polygons in TileMill/PostGIS

In OpenStreetMap there are sometimes multipolygons where attributes are present on both the polygon and the multipolygon relation, such as the Grampians National Park: ...
4
votes
0answers
230 views

GPS data based track/trip calculation algorithm available?

Currently I'm receiving position data of moving assets every 90 or 120 seconds (depending on the asset). What I'd like to achieve now is to detect standstill and movement phases (tracks/trips) on the ...
4
votes
0answers
283 views

Translate Orientation from Sensor data to Geo location

I am tracking a device that might loose GPS signal then and there. And when the GPS signal is too low, I should use the accelerometer and Gyroscope sensors data to guess which way they should have ...
3
votes
0answers
39 views

Clustering driven by an enum/list

Given a set of 2D points ( or vertices if you want ), the values stored for each point are: coordinate on x coordinate on y an enum or a value from a list in general for the sake of this example ...
3
votes
0answers
213 views

Pipe Network: Computing the inflows for systems with multiple reservoir (input source)

Let's say, for the sake of simplicity, we have the following Y Shape water pipe network: S1 and S2 are the reservoirs ( input source), Sout is the water demand where water is drawn out for ...
2
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0answers
55 views

ArcGIS - Flow Direction (Algorithm)

I am curious about the algorithm of Flow Direction in ArcGIS. Recently I am studying about Hidrology, and I have some questions regard to Flow Direction in GIS. The size of this cell is 100m x 100m, ...
2
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0answers
99 views

Is Hershbergers improved Ramer-Douglas-Peucker algorithim worth implementing?

Here is the article with code samples Other than the C code he wrote are their any implementations? Is it worth making a python or R module out of the C code? Are their known flaws to the algorithm? ...
2
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0answers
35 views

using MCA in GIS for suitability analysis

I have an essay about using MCD methods to solve suitability analysis. I must write a scenario about fuzzy membership, WLC and AHP. I feel that I’m confused about when and where to use each method. ...
2
votes
0answers
451 views

How to calculate grid convergence (True North to Grid North)?

I would like to know how to calculate the grid convergence angle between True North and Grid North for UTM maps. I am using ArcGIS 10.0 (ArcView licence) and have used the Calculate Grid ...
2
votes
0answers
89 views

How to detect turns of a route?

I'm doing a Python simulation of a vehicle, driving along a specified path. I generate dummy GPS readings, that fetch the current position of the vehicle, with some randomized error added. After a ...
2
votes
0answers
64 views

How to add nodes into graph

I'm new to qgis and in here I want to find a path between two selected points on the map(Roads-vector layer). The points are selected by the user, using mouse clicks. So here I used the astar ...
2
votes
0answers
55 views

What graph traversal algorithm should I use?

I would like to write an algorithm which can traverse a graph and hopefully later I can implement it to use for an indoor navigation system. The graph would come from floor plans of a building and the ...
2
votes
0answers
203 views

Iteration based positioning on Matlab - retrieving coordinates between iterations

This is my first question on SE so let me know if I'm not asking my question in the right place. So basically, I have an algorithm which uses UMTS measurement events for positioning estimation, which ...
2
votes
0answers
155 views

oil palm stand census algorithm

Anyone have experience in oil palm stand census using tree detection algorithm from satellite images in ArcGIS or QGIS? any references for usable algorithm? What is the accuracy? thanks for help.
2
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0answers
142 views

Placement of a fixed-radius circle on a sphere to maximize point containment

There are many papers on the "Circle Placement Problem" in 2D Euclidean space, but I haven't been able to find any papers discussing this problem on the sphere. The problem is: given a set of points ...
2
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0answers
883 views

Help with Shortest path Algorithm for enormous bus routes database

I am building a bus routes map for Chennai. I use Postgis. In our database we have one table having all the routes along with unique ids given for them. Second table comprises of bus stop names with ...
2
votes
0answers
81 views

How to reduce trajectories with Bellman algorithm?

I need an algorithm to reduce trajectories with Bellman algorithm. I haven't found anything searching in Google. Can someone help me? It would be cool have it in MATLAB. Thank you
1
vote
0answers
76 views

Available modules/products for GPS+IMU sensors shipped with sensor fusion SW?

Are there any solutions/products (modules) in the market that integrate GPS and IMU sensors that come together with the sensor fusion algorithms (Kalman filtering etc.) implemented and ready for use? ...
1
vote
0answers
79 views

library for minimum bounding box “by width” in javascript or python

I'm looking for a library (or at least a code snippet) to calculate the minimum bounding box "by width" in javascript or python. Below is an illustration from the ArcGIS documentation of that ...
1
vote
0answers
11 views

Getting incorrect results for Geary's Coefficient algorithm (incorrect math?)

I'm not sure if anyone here can help me with this, but I'm currently working on a program that uses a spatial autocorrelation algorithm to analyze patterns in an image. It's supposed to return values ...
1
vote
0answers
30 views

How can I automatically make new computings after I have modified some value in a field in ArcGIS Desktop?

I'm a computer programmer and I have no idea about geographic things. I have got a long algorithm with a lot of computings, computed from a previous computed field. There are 7-8 computed fields and ...
1
vote
0answers
84 views

Free implementation of Polynomial Approximation with Exponential Kernel (PAEK) algorithm

I need a Free (i.e. Open Source) implementation of the Polynomial Approximation with Exponential Kernel (PAEK) algorithm, preferably in C, C++, Python, Julia or R. The algorithm is one of the methods ...
1
vote
0answers
23 views

Buffering/extrusion of a dem surface

I have a surface representing a DEM and i would like to add it some thickness. If i simply duplicate the surface and translate it down by my thickness, i get non uniform thickness, ie thinner where ...
1
vote
0answers
42 views

Calculate distance in point collection algorithm

I've got collection of points which are sorted by x,y and distance between n and n+1 (array of objects [{x:0,y:0},{x:1,y:1}....] I would like to calculate distance between all points (point 1 distance ...
1
vote
0answers
148 views

What steps does SAGA GIS take when calculating Topographic Wetness, specifically when handling depression filled (by ArcMap) DEM

I am a grad student involved with hydrological modeling. In the model I work on, we are calculating the Topographic Index (TI; without transmissivity - or set to 1) using Quinn's MFD algorithm. We do ...
1
vote
0answers
147 views

How to Calculate Geolocation Intersection of Two Vectors?

I'm unfamiliar with much GIS terminology but am tasked with solving a specific geolocation problem. For what it is worth, this is for an iOS project, so the data I can collect for analysis is that ...
1
vote
0answers
48 views

What are problems & biases stemming from mathematics behind using Monte Carlo Markov Chain to make heatmap?

My buddy and I are using Monte Carlo Markov Chains to make a heat map - in the interest of rigour, and out of curiosity: "What are the problems & biases that stem from the mathematics behind ...
1
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0answers
112 views

Line defined by two geographical points crossing circle area with defined radius

I'm trying to calculate the amount of lines defined by two geographical points crossing a circle area defined by a center and radius. I've tried to use algorithm discussed here, but in my case it ...
1
vote
0answers
214 views

Divide polygon evenly based on lines and intersection points

I have this purple polygon illustrated in the figure below. I would like to split the polygon so that each line segment (green) split the polygon evenly with the surrounding line segments. A line ...
1
vote
0answers
115 views

Kalmanfilter GNSS IMU

I want to make an uncoupled Kalman filter. The input data are GPS and the output of my strapdown Algorithm from the IMU. The Strapdown Algorithm is used to calculate the actual position and velocity ...
1
vote
0answers
50 views

Indexing GIS data associated with user with timestamp

I have data for each user in this format user1:(timestamp,lattitude,longitude) user1:(timestamp1,lattitude1,longitude1)..... Here the 1 at the end of timestamp/lat/long is to specify a different ...
1
vote
0answers
101 views

An algorithm for locating candidate labelling boxes within a polygon

Has anyone implemented this algorithm In PostGIS? Quoting from the paper: Vector-based geographic information systems usually require annotation, such as a polygon number or attribute data, in a ...
1
vote
0answers
70 views

Allocate places according to distance

I've asked this over on Stack Overflow but thought that someone may have a GI point of view that may help: As an over-simplified example I have a list of events that have a maximum attendance: ...
1
vote
0answers
97 views

How can I assign road names from OSM to gis linestrings using open source tools?

Starting with a shapefile of linestrings I want to assign street names to these lines if there is a match with a road/street in OpenStreetMap. There are no exact matches as the linestrings have a ...
0
votes
0answers
13 views

Build Polygon from point in plain data

How to Build Polygon from point in plain data? I am programming in c++ a software for yield analysis. The software takes data from yield operation Almost 10.000 point are processed. The raw data ...
0
votes
0answers
15 views

automatic extraction of dtm using grass gis

i have generated dsm using erdas lps tool which is in img format. i want to import this file in grass gis and extract dtm. can you please tell me how to input the data , in which format it should be, ...
0
votes
0answers
20 views

Recommendations for route optimization algorithms to handle more variables than just distance

I'm researching route optimization algorithms for my graduate supervisor. He'd like an algorithm to optimize routes for the local library's "library-mobile" that will travel to various neighborhoods. ...
0
votes
0answers
41 views

Where to find more detail on algorithms used in ArcGIS Desktop's location allocation solver?

Where can I find more detail on the algorithms used in ArcGIS Desktop 10.0's location allocation solver? The help file specifies the following: The location-allocation solver starts by generating ...
0
votes
0answers
27 views

Algorithm to scan a road network geometry using directions service

Let's suppose there's a Directions Service which, given a pair of points, returns the geometry, along the network, which best connects those points (which are previously projected - "snapped" - to the ...
0
votes
0answers
16 views

Is there a Minimum Cut Network Delineation Package in QGIS?

Currently I am working out how to best subdivide a pipe network into respective areas. One of the best ways to delineate this network is to subdivide the region into strongly connected areas such that ...
0
votes
0answers
30 views

A Distributed Cost-Distance Algorithm

I'm currently trying to implement a distributed cost-distance algorithm, however I can't seem to invent my own and still make it fast. I've been googling around a bit but haven't found anything that ...
0
votes
0answers
22 views

Tools to generate all the possible geometries meeting specific constraints

I have an area = 2d polygon (generally a 4-side shape). I would like to generate all the possible rectangles matching the following constraints: that fall within the surface of the area with a ...
0
votes
0answers
21 views

PRN (p-code) to Geocode Conversion

I think I have a unique situation. Client has a file containing the old p-code / PRN but can't relate this to a specific address and desires to move to a geocode orientation. Does anyone know if a ...
0
votes
0answers
26 views

'QgsGraph' object does not support indexing

Traceback (most recent call last): File "/home/kasun/.qgis2/python/plugins/floogin/floogin.py", line 246, in findRoutes path=self.astar.astarSearch(graph, start, end) File ...
0
votes
0answers
13 views

Convert ECF to Suface ECF

I'm using the 3D Earth WorldWind Model and I have a path that I want my object to travel. I set the the destination and interpolate to the end point from my current location. The problem is using ECF ...
0
votes
0answers
114 views

Algorithm to find coordinates at selected intervals along a polyline?

I am developing an algorithm to search down a river at selected intervals and return the coordinates. See below: def Downstream(start, interval, data, offset=0, out=None): if out is None: ...
0
votes
0answers
65 views

return to newline arcgis/arcSDE/postgres labeling

i have two tables : parcel and owners with many to many relation ship so i want to print owners name in my parcels (type polygon), so i coded using .net a function that create field in parcel ...