# Tag Info

17

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): ...

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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.

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

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

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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 ...

7

(This is really a comment on the first answer but I don't have the rep to post comments.) It's unlikely that any conformal projection would do the job: by definition they preserve shapes, whence they should not anisotropically distort distances. That rules out the Mercator. Equal-area projections are a good bet: they all attain their equal-area property ...

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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 ...

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

4

You could try this in two different ways, either rotating your symbology (mark each location with a symbol that points at ), or rotating a label (each location has a static point symbol, and label rotated). Here's the Esri help page for each method: Rotate the label: Setting label rotation using a numeric field. I think this would work better for your ...

4

Create nice unique id for lines Convert them to 3d using interpolate shape tool Create field fromZ in above. Use field calculator to populate it, parser Python !shape!.firstpoint.z Populate field toZ, using lastpoint.z Join 3d lines back to original, using unique id, select ones where fromZ < toZ Use flip edit TOOL to flip selected. It works for single ...

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/

3

Add an overlapping Marker Symbol line and make the Template as shown. For the marker symbol I used the Dimension Style set Solid Triangle 2 which points to the right. I resized it down from 18 points to 12 points. Now I have a question for you. For the line ends marker I tried using the dual arrows and a green circle with a dot like you showed, but the ...

3

For MapInfo there is a tool called Rotate Symbols under the Tools menu. This will allow you to rotate symbols based on a fixed value or an attribute value in a specific column. There is a tutorial available here with detailed instructions. Within ArcMap this can be done on the symbology tab of the point layer properties, using Rotation under the Advanced ...

3

You can try to use a Spatial Query. Just define the geometry, and you will get features depending on that geometry. // create a spatial query filter ESRI.ArcGIS.Geodatabase.ISpatialFilter spatialFilter = new ESRI.ArcGIS.Geodatabase.SpatialFilterClass(); // specify the geometry to query with spatialFilter.Geometry = searchGeometry; // perform the query and ...

2

Sure, you could define a mercator projection with the central meridian on top of your dataset, and fiddle the standard parallels parameters

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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

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 ...

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 ...

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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 ...

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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_Widthâ€”The ...

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You can edit the style of your output line layer (Layer Properties > Style) and change the Symbol layer type from "Simple line" to "Marker line" to automatically add more symbol layers: You can choose the shapes you want the line to consist of (in this case, arrows) along with other options such as intervals, widths and angles of the symbol. Hope this ...

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With ArcGIS for Desktop Advanced, you could Convert all depression lines vertices to points (with Feature Vertices to Points) Convert all vertices back to lines (with Points to Line, with the Close Line option checked) Revert the direction of all lines (with Flip Line).

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It's not currently integrated but it is posted as an idea for future releases: http://ideas.arcgis.com/ideaView?id=087E00000005AhRIAU

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When considering turns as features in a network dataset, they must be modeled first. That means you have to create an actual turns feature class that has its own geometry to be traversed. When turns are not specifically modeled (ie, the Global Turns properties you mention) they aren't features that are traversed, just analysis variable properties, which is ...

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Use the GeoServer SQL view feature, and SQL's ST_Project like, SELECT id, ST_SetSRID(ST_MakeLine( ST_MakePoint(lon,lat), ST_Project( ST_SetSRID(ST_MakePoint(lon,lat),4326)::geography, distance, pi()*azimuth/180.0)::geometry ),4326) AS geom FROM mytable; If you have long lines and want to plot them as great circles on a ...

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I actually figured this out with some fiddling. Here's how to do this: Open "properties" for the layer in question Navigate to the "Symbology" tab When classifying data by quantity, click the "Advanced" drop-down menu under the symbol window Click "Rotation" Choose the attribute field with your directional data, and select your rotation style (geographic ...

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Use ST_Affine to make a shifted geometry; Use ST_ConvexHull on each pair (original and shifted) to create a "directional buffer".

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A strikingly similar Q/A is here. Their question discusses finding the shortest path from a point to a coastline and the answer to their question gives a bit more detail on how to use the GRASS v.distance tool. Give it a shot. Basically, input your points as the 'from' layer and the coast as the 'to' layer. A new vector map can be created with lines ...

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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 points,...

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