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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2
votes
1answer
49 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
166 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
52 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
65 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
50 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 ...
1
vote
1answer
246 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
23 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
73 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
197 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
67 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 ...
0
votes
0answers
20 views

grass: walking along vector line

I have a line vector which I converted into points with v.to.points. I need to get the coordinates of each point AS I WOULD WALK ON THE LINE. v.to.ascii appears to just use some other order, but I ...
1
vote
2answers
127 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
120 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
62 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
52 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
186 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
70 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
344 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
123 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
130 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
529 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
685 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
121 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
27 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
83 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
162 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
87 views

QGIS how to compute a trendline of two point lines?

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
415 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
32 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
3
votes
2answers
364 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
358 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 ...
0
votes
0answers
41 views

grass plugin in QGIS all of sudden not working as expected

The previous week I was able to use the grass scripts in the QGIS 2.0.1 Dufour toolbox, but today they do not seem to be working. I am not sure where to place a '-c' which was a solution to the same ...
3
votes
1answer
117 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
73 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 ...
1
vote
0answers
169 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
105 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
118 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
110 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
880 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
145 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 ...
2
votes
1answer
156 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
97 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 ...
1
vote
1answer
128 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
66 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
70 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 ...
2
votes
1answer
127 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.
0
votes
0answers
55 views

Uploading transmission line shapefile into spatialite.

I merged around 70 different transmission lines shapefiles of a state into one. Then, with a grid I divided the state into many features and got the centroids in QGIS. I'm trying to calculate in ...
1
vote
0answers
145 views

Sources for German Standardized Symbols in QGIS

German Original: Gibt es für QGIS eine Phytonerweiterung "Planzeichenverordnung"? Zur Bearbeitung von Flächennutzungsplänen und Bebauungsplänen kommt man an den Planzeichen nicht herum. ...
2
votes
1answer
195 views

What's the unit of measurements produced by “sum line lengths”?

My goal is to find the total length of roads per county for a particular state. You would think there would be a simple government spreadsheet with this information in it.... I cannot figure out how ...
4
votes
1answer
173 views

extend line to feature. programatically

Thanks in advance for any help. I'm trying to programmatically extend hundreds of lines (blue in image) to a single polyline feature (red in image). Sometimes the lines intersect each other, but I'd ...