A set of ordered co-ordinates that represent the shape of geographic features too narrow to be displayed as an area at the given scale (contours, street centrelines, or streams), or linear features with no area (county boundary lines)

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1answer
295 views

Switch line direction for PostGIS-lines in QGIS or Pgadmin

I am trying to switch the line direction in a PostGIS-layer. The postgis-geometry column is e.g. "LINESTRING(0 0, 1 1, 2 1, 2 2)". The reason is that my symbology is direction-dependent, but I drew ...
0
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1answer
47 views

How to create segments/lines by inputting coordinates

I have a set of coordinates and I wisht to recreate them in GIS. Basically, I am following from a paper based sketch map of maritime delimitation.
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0answers
115 views

Method for identifying upstream segments

I need to add to the attribute table of a stream network layer a column that can identify all upstream segments that contribute to the segment (for each segment). My best idea at the moment is to ...
1
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0answers
1k views

Splitting polyline by points using ArcGIS 10.2 for Desktop?

I have a layer containing a curved polyline and I would like to split it at multiple point locations, which I have in another layer. In ArcGIS 10.2, I can do this with the tool "Split Line at Point". ...
0
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2answers
322 views

How to find when train nears station? [closed]

I am creating an app for tracking trains. When the train comes near to a railway station the system should identify it. To do that I want to gather GPS coordinates near the station and save them. ...
1
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2answers
992 views

Openlayers: Get Start and End Points of Line Vector Features

I'm trying hard to get start and end of lines from a vector. The line vector is loaded from a kml-file. For now, I tried to iterate over features in the vector and grab the start point and put it in a ...
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0answers
27 views

Creating separate Polylines from Points using ModelBuilder and Python Script Tool? [duplicate]

I have a list of coordinate points (long and lat) of 4 locations (points 0, 1, 2, 3) saved as a feature class shapefile. I want to create a polyline that will connect points 0 and 3 and create a ...
2
votes
1answer
1k views

Split a line feature using nearby points

I have a line shapefile and a point shapefile, and the line has its own segments and its attribute table, the point shapefile has points near the line above, not on it and the close look,...
2
votes
1answer
1k views

Why does clipping a line layer using a polygon result in an empty shapefile?

I am using QGIS 2.2.0 and want to clip a line layer (roads) so that only those inside a polygon are shown. When I do this using Vector->Geoprocessing Tools->Clip I only get an empty shapefile as an ...
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1answer
120 views

How to make river lines intact between confluences in QGIS?

I got a river shapefile below, and I found that there are many fragmental lines in this line shapefile, like, and, Most of these are located around the confluence(node), and how can I do to ...
0
votes
1answer
630 views

Creating distributive flow line map showing movement of passengers from bus terminal to several destinations? [duplicate]

I'm writing my final year B.Sc thesis on transportation (pattern of passenger flow from a bus terminal to several destinations). I intend to use a distributive flow line method of spatial movement ...
10
votes
1answer
11k views

Draw lines from points in QGIS

(I found here similar questions but they all reffer to ESRI's programs, and I use QGIS) I have a point layer and need to draw a line passing through or in the vicinity of the points (up to 0.5m ...
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0answers
57 views

How to create a point representing a polyline?

How do I convert a line (usually 2 vertices but can be more) into a single point in QGIS? I did it a couple of years ago using a build-in tool in ArcGIS 8 or 9 I think but have no idea how to do it in ...
0
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1answer
113 views

CartoDB simple process

I'm attempting to create a simple process with CartoDB, I have a layer with number of polygons, I want to to run a SQL with a multipoint line to report which polygons were intersected.
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2answers
134 views

How to number points along a line consecutively

I have a line and along this line I have different points which are max. 20m away from that line. Now I would like to number the points along the line, like shown in the grafic. Any suggestions how to ...
6
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2answers
1k views

Need to merge overlapping line segments

I'm working with fish distribution data, and have combined several 24k habitat maps into a single layer that I'll call "critical habitat" In merging multiple distributions into one dataset, there are ...
0
votes
1answer
44 views

How to do a search in a line to a specific point

I'm using QGIS 2.0.1 Dufour. I'm working with a shape file made by a single line that represents a road with 30km. In that line I want to attach pdf files containing information about some points in ...
1
vote
1answer
252 views

Line bearing for wind direction for plume of smoke QGIS

I'm trying to draw a line representing direction of a plume of smoke for an emergency planning scenario in QGIS. The line needs to be 5km in length and have a bearing of 85 degrees. The closest I have ...
5
votes
2answers
361 views

How to calculate the area between two line shapes?

I'm a newbie using QGIS (2.0). I'm trying to calculate the sidewalk area of a city. For that I have some shapes, extracted from Mricostation, with the topology (facades, fords, fences, etc.), but ...
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0answers
27 views

Show the paths but not roadsides and driveways in the line layer

I want to display paths in the woods but the paths are all in One (line) layer that contains all roadsides, pavements, drivvays, but also paths, tractor road and other relevant roads in, and up to the ...
2
votes
1answer
583 views

Fading symbology at edges

A general problem for me with digitized material is that it can be too precise. Sometimes I just need to show a line or surface without sharp borders. I don't regularly need to visualize the exact ...
2
votes
1answer
210 views

How to check how much of a line (percentage-wise) is covered by a polygon in arcpy?

I'm searching for an efficient way to check if a line is covered by a polygon (see image, this case should return 2x "true"). Right now I only check wether a line is within a buffer with line....
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2answers
475 views

Draw great circle rays from a single point along specific directions

How can I draw great circle rays starting from a single given point P (for example, from coordinate [34 N, 116 W] in this map) and along directions D1, D2, ... (for example, 30, 45 and 135 degrees) in ...
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2answers
150 views

sql query to get origins and destinations

I have a table of cities with an ID and geometry (200K rows) and a table of travels, with only two ID: idfrom, idto (7K rows) I'm wondering how could I select the geometries for each one in order to ...
4
votes
1answer
199 views

Split single line based on the 3D length

so I have a transect line which I already add the z value using the Interpolate Shape. I need to split this line into 100m in 3D length, which due to elevation must be different than 2D. However the ...
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0answers
216 views

erase a “line feature” (erase feature) from a “polygone feature”

how can I erase a "line feature" (erase feature) from a "polygone feature" (input) in ArcGIS 10? With the tool "erase" I can only use an other "polygon feature" as erase feature for a polygon (input)....
4
votes
1answer
2k views

How to assign node IDs to links in a network?

I have two shapefile layers in ArcGIS for Desktop 10. I have one line layer and node layer. My node layer(shp) has a "code_1" field and line layer has a "code_node" field. The intersection point ...
0
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1answer
34 views

cut off part of catchment

I want to edit a polygon as that I cut off a part of it. I want to freely make a line that define where the polygon should be seperated. I have tried to useedit vertices but it does not seem to be a ...
0
votes
2answers
89 views

Show only some buildings

How do I show only some buildings? I only need to show 3 cabins in the forrest, but not every house in the whole village around, and the city close by. Maybe some of the symbol buildings in the city ...
3
votes
1answer
352 views

Show alternating contour lines

Is it possible to show only every other counture line? And how do you do that? (Im new to QGIS Lisboa 1.8.0, but even newer to QGIS Dufour 2.0.1, but have used ArcGIS a bit a while ago, and also ...
3
votes
0answers
196 views

Find the co-ordinates of tangent points and intersection of a curved line [closed]

I have a line with curves in it. Is there an easy way to extract the X Y values for the tangent points and intersection points in ArcMap 10.2.1? Hopefully my simple paint diagram clarifies what I ...
1
vote
2answers
158 views

Can I clip vector shapefiles more efficiently?

I have a river shapefile, got from r.watershed module, and it looks like this: I have eight points on the river which I want to analyse, and I only want this river segments:(the second photo below ...
0
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2answers
440 views

Explode/Decompose Polyline Network with MapInfo

I have a network of polylines which possibly include multi polylines as well. I wish to decompose these polylines into their fundemental line segments so I can produce the following table: Link_ID | ...
4
votes
1answer
310 views

SLD - Is it possible to create a Rule that stylise only the first and last point of a Line?

I've read the SLD doc, but I can't find any clue on how to create an SLD file to add a graphic symboliser on the first and last point of a line. Does someone know how to do that ? Thanks.
1
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1answer
121 views

Calculate 2D line of site from line layer and polygon layer using ArcGIS 10

I'm trying to run an analysis where I need to clip a radiating lines layer by land features to get the maximum distance from the central point to the nearest obstacle. What I have is a large line ...
4
votes
2answers
2k views

Extend Polyline in ArcGIS without intersecting line

I am trying to extend the ends of each line I have in a seismic survey 2 miles. I have tried using the extend line (Editor) tool but it needs an intersecting line to move to. Does anyone know how to ...
0
votes
1answer
131 views

How to find line segment between line intersections?

Given 1 non-self-intersecting line (red) and 2 other non-self-intersecting lines (light-green), what is the best way to find the coordinates of the line in between the 2 intersections? I threw this ...
4
votes
1answer
2k views

ArcMap 10.1 SP Spatial Join Problem (lines within polygon)

I have a line layer (faults) and a polygon layer (fishnet grid). The fishnet has a risk of earthquake attributed to each polygon. I want to take that risk value and give it to the fault lines which ...
2
votes
1answer
291 views

Writing an algorithm to find the most efficient line angle at which to draw lines

I've written a tool that fills a polygon in ArcMap with parallel lines at a user specified distance apart and at a user specified angle, written in vb.net and arcobjects. What i'm looking to do next ...
5
votes
2answers
328 views

Can someone clarify some details about freehand line tracing in QGIS?

I have read several tutorials and questions here on this site, but I have some lingering questions/doubts that I would like clarified. My project is tracing roadways from a 1926 map so that I can ...
2
votes
2answers
4k views

Fastest way to Join tables in python automation

My issue comes form the fact that doing Joins manually is actually relatively quick (5mins), but python automation of this process is 6hrs! Here is my code: import arcpy GDB_MARK_TO_MARK_VECTOR_VIEW ...
1
vote
1answer
3k views

Geoserver SLD Line styling with external graphic instead of WellKnownName

I have problem with styling in geoserver. Using tutorial from http://docs.geoserver.org/stable/en/user/styling/sld-cookbook/lines.html#id7 everything is ok but when I want to use ExternalGraphic ...
3
votes
1answer
158 views

Tornado Data Points: Linking 2 Points in QGIS on the Same Row

So I've got these tornado .csv files that have two latitude & longitude entries with the left-most in the table being the beginning point and the right-most being the ending point of the tornado, ...
0
votes
1answer
49 views

How to make XY to Line dynamic to access query?

I have connected the Access file to the ArcGIS file, and displayed it using the tool XY to line, but when I change the access file, this is not automatically adjusted in the ArcGIS template. Somehow, ...
1
vote
0answers
138 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
2answers
343 views

How to extract common outline of multiple polygons with code?

I'm not really asking for a chunk of code to do this, but more of an algorithm I can work with myself. For example, this is the state of Maine, obviously, and I have the points of each county ...
1
vote
1answer
256 views

QGIS how to compute a trendline of two point lines? [closed]

Does anyone know how to compute a trendline for two lines of points? I have two lines of points of a 10 km long urban road. 1st line is one driving direction and the 2nd line of points ist the other ...
3
votes
3answers
1k views

How to draw (or add) a line indicating a specific latitude/longitude?

I'm trying to add a single line that show a specific latitude (e.g. the Tropic of Cancer) I don't want a gird but only a single line even in a vector layer.How can I do that I've try with pyQGIS ...
2
votes
1answer
43 views

Get coodinates from point shapefile

I converted a line shapefile to points as you can see in the attached image. Is there a way to know the coordinates of each point? Any help would be really appreciated! PD Im using QGIS 1.8.0
1
vote
0answers
284 views

Line features into polygon features

Can any one tell me how to convert line features into polygon features in ArcGIS. I am using ArcGIS 10. I searched the arc toolbox for any tools for this conversion, but I couldn't find any. Please ...