The distance-independent relationship between two points in space that specifies the angular position of either with respect to the other

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15
votes
2answers
3k views

How can I calculate the bearing between two points in PostGIS?

How can I find the bearing between two points in PostGIS? Please specify in your answer whether or not the method producing a bearing on the spheroid, or a planar bearing.
10
votes
2answers
250 views

Which weather on my road? Looking for a spatial weather forecast web service

My friend Bob goes from A to B leaving tomorrow morning at 6:00. There are many direction services that indicates him short, fast and/or cheap routes. Bob does not like to drive under the rain and ...
6
votes
1answer
445 views

What determines “west” in Antarctica?

Hopefully this isn't so far afield as to get banned - apologies in advance to those who think it doesn't belong. This article discusses a region of Antarctica which is described as "West Antarctica". ...
6
votes
1answer
579 views

How do I find least cost path over a DEM based on slope magnitude and direction?

What sort of algorithms can I use to find a least cost path through a DEM where it costs more to traverse a cell going downhill or uphill than it does to follow the contour of the land? All the ...
4
votes
1answer
239 views

Understanding percentage drop-raster (flow direction-tool)

I'm creating a Topographic Wetness Index using a python script (http://arcscripts.esri.com/details.asp?dbid=16750) As I don't want this just to be a blackbox, I'm trying to understand the different ...
4
votes
0answers
123 views

Advanced GMaps directions

I try to create an application for taxis. The application will be GMap based. On the map will be marked the region in which the taxi driver is working in. The region will be a polygon designed by ...
3
votes
2answers
1k views

How to show polyline direction in ArcGIS for Desktop (ArcMap)?

can someone tell me how I can show the direction of a polyline as it was digitised? I need this to check if my network analysis is obeying one way streets...I know of a tool in Xtools that can do this ...
3
votes
1answer
391 views

How to get the Flow or directional raster map using GRASS?

Aside from using r.fill.dir in GRASS, is this the script to produce the Flow or directional raster map? Is this the output for the script ...
3
votes
1answer
49 views

How to display bidirectional flows?

I'm working on a map showing oil shipping. Basically, I have a a series of nodes/line segments that make up the shipping network. I've joined the sums of oil that traveled along each node, so can ...
3
votes
2answers
67 views

How to deal with Roundabouts in PgRouting

Can anybody guide me to to deal with roundabouts in pgrouting?? I have some roundabouts in my road network and when i try to make route from one point to another, it gives me wrong direction where it ...
3
votes
1answer
319 views

Is there an open source directions webclient for pgRouting like the directions API from Google?

I am looking for an open source webclient with (Google) directions functionality (like draggable lines to create extra waypoints) based on an pgrouting database (with an osm2pgrouting topology). I ...
3
votes
1answer
443 views

Driving directions and multi-modal route planning service for a city with OpenStreetMap data

First off I'd like to mention that I've never come close to anything-GIS until a few weeks ago when I thought of this. So please expect some layman's questions. I'm looking to create driving ...
2
votes
2answers
416 views

how feasible is building my own map server? providing GeoCoding, Directions and Navigation

My need is a heavy use of routing. same as Google's Directions API. I'm looking for a viable alternative to abusing google and paying them too much. how difficult is it to have my own server for that ...
2
votes
2answers
198 views

Working out parcel direction

I am looking at applying a direction indicator to land parcels and houses (in MasterMap). effectively, I am looking at applying a direction indicator to the land and the buildings associated to the ...
2
votes
1answer
23 views

How to detect other objects are on which side of an object based on lat long

I am working on a system that detects the lat/long of vehicles. I want to track other vehicle's position: left, top-left, right, top-right, bottom-right, bottom-left etc based on lat/long. I have ...
2
votes
2answers
402 views

How to display arrows on pipes from upstream to downstream using QGIS?

I am trying to display arrows on pipes of a sewer network so their direction is from upstream to downstream edges of the pipes. I have managed to display those arrows on a polyline layer (which is ...
2
votes
1answer
165 views

Knowing acceleration, gyro and compass data how to calculate north direction [closed]

I have a small video camera with an attached sensor. I can get from the sensor his acceleration, gyro and compass data. Knowing this data I need to rotate the camera so that it will look strictly ...
1
vote
2answers
60 views

How to convert Direction Of Travel OSM vectors from a “system” to another?

I have a painful doubt according Direction of Travel (DOT) vectors in OSM data. I'm using ArcGIS10, and a OSM data shapefile. I have a OSM road layer, that has many "Both ways" vectors and many "One ...
1
vote
1answer
66 views

Calculating field length in certain directions (raster)

Currently I'm working on winderosion. For my purpose I like to calculate the length of agricultural fields in certain wind direction. I would like to do it for raster. To be more precise: I have ...
1
vote
1answer
234 views

Small Idea to get best path between two points

Guys I don't know if its a good place to post ideas or to ask general questions. Still as the question is related with maps service, I am posting it here. If it's not the right place, please move me ...
1
vote
1answer
2k views

google maps V3 : in javascript api, render route obtained with web api

I have to obtain route directions with the Google maps v3 WEB (http request) api (computations are made server-side, based on this data, without client interaction, so no JS available). Then, the ...
1
vote
1answer
28 views

How can I calculate the nearest distance to a landscape element taking the direction into account (i.e. slope direction, prevailing winds)?

I am trying to build a layer of distance to relevant landscape elements in a watershed. To be relevant, a landscape element must be downstream with respect to the runoff direction.  Clearly, I want ...
1
vote
0answers
54 views

How to deal with direction in pgr_ksp (K shortest path)?

I am working on a android app for navigation with PostGIS and pgrouting. I have implemented pgr_dijkstra and its working fine. I am not considering direction in routing at this point and just want ...
1
vote
0answers
327 views

Arrow flow lines from a contour map

using QGIS (or even GRASS) is it possible to label a contour lines shape with arrows that indicate the flow direction? Briefly: I have a point shape with elevation values. I make an interpolation map ...
1
vote
0answers
78 views

How to indicate a change in transport mode for directions in a multimodal dataset

When I solve a route and generate directions for my multimodal dataset, the end product is not very user friendly: The pedestrian started walking along Main Street and then boarded a bus to travel ...
1
vote
0answers
210 views

Avoid backtracking while creating loop in Google Map API 3

I am trying to build a solution where i would create loop by google map. My first and only business rule is there should not be any repeated route. But with my demo ...
0
votes
1answer
82 views

Does OSM data contain the direction of travel?

I was looking for Direction of Travel (DOT) information inside OpenStreetMap shapefiles, but only I've just found "ONEWAY = 1 or 0", but nothing about its direction. If I work on an OSM editor, I can ...
0
votes
1answer
56 views

Determining direction of longest segment of polygon?

I have a shapefile with 9000 agriculture fields and what I like to do is to determine for each field (=each polygon) the direction of the longest segment. For instance, the selected polygon in the ...
0
votes
2answers
37 views

Using grayed out distance/direction tool in ArcGIS for Desktop?

I have a set of five points (all with specific latitudes and longitudes) and I want to create a set of points which will be about 80 kms from the first set. I understand that I can use the ...
0
votes
1answer
83 views

Distance-direction computation of lines with exactly/more than two nodes?

A distance and direction tutorial provided as an Answer at How to add Direction and Distance to attribute table? uses: xat (0 ), xat (-1 ) and yat (0 ), yat (-1) for start and end points of lines; ...
0
votes
1answer
68 views

How to compute and fill One-way field in a street shapefile according spacial position

I think it is something complicate, but I hope someone could bring up any idea about. I'm using ArcGIS10, and I have a "One-way roads" shapefile with a One-way field with Y/N. But I need to create a ...
0
votes
0answers
23 views

GRASS, cell count in one direction

I have tried but failed to do the following: For a cellular automate process, I want to include a minimum amount of cell counts in one direction (or direction window). So lets say I have a ...
0
votes
0answers
18 views

Changing tracks to vectors in a grid

This is a version of a question that I posted on the GRASS list, but I didn't get any suggestions there. I would like to overlay a grid (cell size about 500 m x 500m) over an animal track created from ...
0
votes
0answers
30 views

What is proper bearing for plat ties to monuments?

I had a 'discussion' with an engineer about the proper way to describe a bearing on a plat (survey of land) that ties the plat to a known survey monument. He stated that it should be from the point of ...
0
votes
1answer
169 views

Updating a column with line direction in MapInfo

I was wondering if there is a way to update a column in MapInfo with the digitised line direction. I have two TAB files, one is complete lines and the other is sections of the same lines (both have a ...