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)

learn more… | top users | synonyms

1
vote
1answer
151 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
251 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 ...
0
votes
0answers
26 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
293 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 ...
0
votes
1answer
38 views

ArcGIS cutting a line out of polygon

Ok I know that this must be a pretty silly question, but I'm just not able to create a line in ArcGIS. I started an edit session and began with straight segment. All i want to do is simply drawing a ...
2
votes
1answer
80 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 ...
1
vote
2answers
294 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 ...
0
votes
2answers
75 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 ...
3
votes
1answer
119 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 ...
0
votes
0answers
65 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 ...
2
votes
1answer
686 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
votes
1answer
28 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
78 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
260 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
100 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
136 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
votes
2answers
227 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 | ...
3
votes
1answer
119 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
vote
1answer
69 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 ...
3
votes
2answers
526 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
92 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
716 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
176 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
223 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 ...
1
vote
2answers
1k 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 ...
0
votes
1answer
1k 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
137 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
34 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
118 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
226 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
158 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
694 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
39 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
88 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 ...
3
votes
2answers
687 views

Get coordinate of second to last vertex for python ArcGIS

I need to obtain the x and y attributes of the second to last vertex for each segment and add to the attribute table using Arcpy (or some other python module). To get the Y co-orodinate of the first ...
5
votes
1answer
858 views

How can I add an arrow to a line?

I want to have arrow heads at the end of a number of lines. I add these through Line properties --> Line decorations. It looks nice and all when displayed in the legend: But in my map, due to ...
3
votes
1answer
164 views

How can I move along a line (or path)?

Given a line (street, railroad, river...) I want to simulate a moviment inside this line. Example: See this picture: Say I'm in "Nagqu" and want to move to "Kunlunqial". In a time (t=0) I'm in ...
2
votes
1answer
95 views

How to make marker line thicker in QGIS?

I'm mapping railways, find that the usual cross marker line is so thin it doesn't show up in Print Composer at web resolution, and can't find any way of making it thicker, only the main line. Is there ...
2
votes
0answers
291 views

Smoothing Lines in PostGIS

I want to smooth Lines in postgis, to be more specific, I want to smooth road data from OpenStreetMap. Basicly I thought of something like this scenario. This would be a possible road segment. I ...
2
votes
2answers
152 views

Convert point file to polyline but not joining every set of points in ArcGIS10

I have a dataset that looks like : OBJECTID Shape KP DESCRIPTION EASTING NORTHING 1 Point 0.04 Span;Start 525112.2 6728715.4 2 Point 0.0506 Span;End ...
0
votes
1answer
151 views

How to draw downhill path with TileMill and KML?

I have a kml file which contains downhill paths and other points. Here is an example. I imported the file to TileMill and I used Save & Style, but nothing appeared except a few points. I think ...
2
votes
1answer
172 views

Line calculation from KML file

I am a beginner in QGIS 2 and Mac OSx Mountain Lion I need to get line length in meters for different gps waypoints. 1 I import kml file to create a new vector shape (this works fine). The projection ...
6
votes
3answers
2k views

A tool or way to Extend line by specified distance?

I have a purely aesthetic layer which has arrow symbols. Some aren't showing up right because the line is too small. I have selected maybe 50 records where I need to extend this line by a given number ...
0
votes
0answers
252 views

Calculating line direction in MapInfo

I have a large file of a road network. I need to calculate the value of direction (in degrees or radians) of the line segments, and save this value to a new field. I need to use MapInfo. I have ...
1
vote
1answer
195 views

How to discretise a line into grid lines

Having a line and a grid, the aim is to discretise the line into grid lines. In the following figure, the given line is in black, its intersections with grid lines are blue, the desired is set of ...
2
votes
1answer
112 views

Draw a line and a buffer around it onto the spheroid

I need to draw a line between two points and create a buffer around this line. The only difficulty is that I need to draw not a "cartesian" line but a line that is laying on the spheroid. I tried to ...
2
votes
1answer
176 views

Split polygon into lines

I have a polygon layer which looks like this . I used the QGIS multiparts to singleparts tool and also polygon to lines. In both cases i got this type of result . I want to extract polygon into ...
1
vote
0answers
85 views

Convert polygon feature to line feature

I have a polygon shape-file i need to extract the line segments where the polygon features intersect each other and also the segment where they don't. Can we automate this process or can scripting ...
1
vote
1answer
146 views

How to get a centroid of a closed line in MYSQL

I have a table that contains only closed lines (lines where endpoint is the same as startpoint). I would need to find a centroid for those lines. How would I be able to achieve it? It does not ...
3
votes
1answer
173 views

How to convert a line to points?

I'm working with QGIS and I want to convert a line into many points, does someone know how? Thanks.