Tag Info

Hot answers tagged

16

Using ST_Azimuth Planar bearing can be calculated using ST_Azimuth: SELECT ST_Azimuth(ST_MakePoint(1,2), ST_MakePoint(3,4))/(2*pi())*360 as degAz, ST_Azimuth(ST_MakePoint(3,4), ST_MakePoint(1,2))/(2*pi())*360 As degAzrev degaz degazrev ------ --------- 45 225 For spherical azimuth (Quoting potgis-users group): ...


9

Have you looked at a globe lately? :) The prime meridian divides the earth into the western and eastern hemispheres. "West Antarctica" is in the western hemisphere, hence the name.


8

You should be able to use the Arrow At End symbol from the Symbol Selector to show the digitised direction of polylines.


7

For anyone coming across this question now - PostGIS supports ST_Azimuth on geography (spheroid) as of 2.0.0.


5

Since you mentioned that are you doing network analysis, I recommend assigning the symbology for your road edges within the network dataset layer in the TOC instead. You are on ArcGIS 10.2, so here are the steps: Add the network dataset into the ArcMap TOC. Open the Layer Properties dialog box by double-clicking the network dataset layer in the ArcMap ...


4

Line data (of any format, be it GIS/CAD/etc.) typically defaults to the 'direction' of the line being based on start point or first coordinate given to end point or last coordinate given. Direction of travel is therefore considered in terms of with or against the direction of the line. The most common scheme (there can be others) for attributing this in a ...


4

first create the aspect raster with r.slope.aspect then display the arrows with d.rast.arrow.


4

The Weather Underground does this - Road Trip Planner (with Weather) http://www.wunderground.com/roadtrip/ Example Route above: ...


3

Not exactly an answer, but have you seen The Open Source Routing Machine (OSRM) Their routing engine works on OSM-data it seems, but it is opensource, so it could provide som pointers. And their implementation is FAST: http://map.project-osrm.org/


2

The ArcMap Path Distance tools can do this, although it's moderately complex. Specifically, you need to use the horizontal and vertical factors. This looks at the aspect/elevation to figure out whether it's going uphill, downhill, or parallel to the slope, and assigns a different weight to each direction of approach.


2

A) Direction is calculated from the difference between start and end point B) Distance of line is best to be calculated simpy by $length and is the sum of all individual parts Also note nhopton's comment on how to get bearing of each individual segment: A most elegant solution, thanks. I'd mention that if you need to determine the bearing for each ...


2

Assuming you just want the general orientation of the polygon, rather than a specific segment... try the Minimum Bounding Geometry (Data Management) ArcGIS tool with the RECTANGLE_BY_WIDTH or RECTANGLE_BY_AREA geometry type and the MBG_FIELDS option. The MBG_FIELDS option will add the following fields to the output attribute table: MBG_Width—The ...


2

I'm going to suggest an alternative approach here that should get you what you want and still leave the data in a conventional format. As I pointed out in my comments on your other question, if you change the actual one-way attribute you will cause problems using network analysis software and confuse others working with the data because you won't be ...


1

I may have a solution for you. If flow in one direction is consistently lower than in the other direction, this would work. I think you have much of the answer included in the question. I would attempt to duplicate the layer and draw the limited flow on top of the greater flow and have them both symbolized by the flow value.


1

There are 2 possibilities, what could be wrong. (1) You missed to make use of one-way street information as Uffe answered already. In pgRouting this means, that you need to use reverse_cost and then have different cost values for each direction. See the documentation of Dijkstra algorithm for example, and especially look at the "with reverse_cost" example. ...


1

Have you followed the instructions in the tool's help file? If the tool is grayed out, then you probably have not taken the first two critical steps. First, you must start an edit session. If your new points should be in the same database/file, then Editor > Start Editing will suffice. Otherwise you need to create a new database/file to hold your new ...


1

Since you only have 5 points, the following won't take too long. Make sure your layer is editable. In the Construction Tools in the create features dialog, select "Point at end of line" Begin drawing a line from one of you points by clicking on the point. Right click and choose Direction/Length and enter the details. Repeat for the remaining four ...


1

The answer depends on what "field length" means. Suppose the length is the longest segment, oriented with the wind, that is contained within the field. First rotate the data so that the wind direction now appears horizontal (west to east), then apply any of the solutions to this problem for the special case posted at How to calculate the maximum distance ...


1

I apologize that I can't answer how to do it with arcgis but I made a successful test with Spatialite-gui. I created first a new Spatialite database and imported some road data from a shapefile. Then I executed these three SQL commands: alter table roads add column from_or_to; update roads set from_or_to='F' where MbrMaxY(EndPoint(geometry)) > ...


1

It seems that all the values in slopes are rounded to the nearest 0,5. So 0,401 m / 2.8284 m = 0,14177, would instead be 0,5/3 = 16,6667. Or if distance is 2 metres, then 0,5/2 = 25 %. In the manual it says the values are rounded in FLAT areas, which seems to be a little off considering it does that where slope is 25 %. Another remark is that in flat areas ...


1

If you are using ArcMap and representing the sewer network using line features go into the layers properties, change the line type to cartographic line symbol. From there you will want to select the line properties tab. In this window you should see a box named Line Decorations with 4 radial buttons. Select the choice that you need. Once you have done so ...


1

It is possible, but it's not a very efficient way of routing. Very few people would want to use the exact starting & ending point as you. It is much more useful to know which are the roads, which are the directions, and the turns and crossroads. The problem with services like Google maps in India, is that while traveling, we use a variety of ...


1

It's possible but performance isn't going to be anywhere near what you'd expect from google api on a small budget for an entire country. You should try it and report back :) ArcGIS Server and Network Analyst is out of the question given the budget. So go with Postgresql, PostGIS and pgRouting. Route Maker did it for a few countries on 4GB RAM


1

You need to typecast each Object on the JSON response to the proper kind. The web service API also doesn't return the ub property of the DirectionsResult (undocumented property), you need that as well. The DirectionsRenderer expects ub.travelMode, ub.origin and ub.destination (all strings). The origin and destination are only used if you enable the ...


1

I guess this answer is useless 2 years later, but you may want to try OSRM. Not based in pgRouting, but is an Open Source routing engine with a Leaflet based API


1

ITN (Integrated Transport Network) has line direction for the ROADS http://www.ordnancesurvey.co.uk/oswebsite/products/os-mastermap/itn-layer/index.html but for houses/land parcels there is no way - you can add an arrow direction to the digitised line but that will only be the direction the operator drew the original linework to make the parcel polygon. ...


1

You might start with this answer. It sounds like the question is close anyway.


1

I am unsure of anything that already plans routes by weather conditions, but if you were to try to figure it yourself, I would take a look at NOAA/NWS GIS Data. They have both KMLs and Shapefiles for current weather, forecasts, hurricanes, etc.



Only top voted, non community-wiki answers of a minimum length are eligible