Questions tagged [length]

The longest extent of anything as measured from end to end

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49 views

Seeking Brazil wide reference system to compute road length?

I've a Brazil road layer that include start km and end km for each road, some are empties. Have checked and some of the values are wrong so I'll calculate road length by myself. I use ArcGis, but can ...
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1answer
227 views

QGIS object selecting if any segment length is longer than [closed]

I have a polygon layer with generated triangles covering for example district or city area. I need to select all the triangles if any triangle (object) segment is longer than 100 meters. Picture: ...
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1answer
782 views

Measure length of each segment for a polygon in Postgis

I have a polygon table in PostGIS and need to calculate the length of each line segment. How can I achieve this? I have done it in QGIS but would prefer to do it in the database. I have found ...
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1answer
75 views

Calculating length of curved line derived from intersection between two polygons using ArcPy?

I'm trying to get the density of intersection points along their related ellipse. What I'm missing is the length of the arc of the ellipses comprised in between the yellow polygon (which is a ...
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85 views

Identify the length and orientation of the features in P2 relative to features in P2? (ArcGIS)

I try to measure the maximal length and orientation of features in one shapefile (S1) relative to polygons in another shapefile 2 (S2). My goal is to evaluate the spreading of patches of beetle-...
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1answer
276 views

QGIS: Displaying total length of lines in print composer legend

In the print composer (also in the layer selector) I can choose to automatically display the amount of objects in that category in square brackets. That is useful for point features/layers. But in the ...
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1answer
516 views

Using ArcPy to get length of Polyline created?

I am trying to get the length of Polylines I am creating immediately after I create them. The code I am using: arcpy.Polyline(arcpy.Array([arcpy.Point(firstx, firsty), arcpy.Point(secondx, secondy)])...
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1answer
245 views

Changing parallel line length to split polygon in QGIS?

I have a polygon which I want to split with a selected line with a parallel line. I have made the parallel line but it's lenght is not enought to split the polygon. It necessary to be parallel with ...
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1answer
606 views

Can we take the length of a linestring by calculating ST_Distance from its ST_StartPoint and ST_EndPoint?

I took the values of my StartPoint and EndPoint by doing this procedure: a) SELECT COUNT( CASE WHEN ST_NumGeometries(geom) > 1 THEN 1 END ) AS multi, COUNT(geom) AS total FROM public.roads; ...
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1answer
250 views

Postgis different result using st_length and st_intersection

I'm trying a simple intersection between line and polygon SELECT p.id, st_length(st_intersection (l.geometry,p.geometry)) as partial_length, st_length(l.geometry) as line_length FROM line l , ...
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1answer
484 views

Length of line differs depending on query method

We are doing a check of a length attribute against the Shape Length in all our line feature classes (maybe 40 feature classes and 200,000+ features). In the length attribute we round the Shape Length ...
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2answers
155 views

Incorrect length from Flow Length tool

Why is my flow length tool giving value less than one? Isn't a flow length tool supposed to give the maximum length of upstream flow to the cell? Then, how come? I am using coordinate system of GCS ...
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2answers
1k views

How to measure the length/area of a line/polygon by just selecting it?

I can get what I want by using this code but have to do it everytime i select. The geometry of the features are small (city scale). layer = qgis.utils.iface.activeLayer() features = layer....
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1answer
337 views

How to depict line symbols with length from attribute

I want to depict angled drill holes as a horizontal traces (plan view). I have a CSV file with X,Y,Azimuth and Horizontal length. Using the simple marker I can get a line pointing in the right ...
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1answer
102 views

How to divide and split an arc into specific lengths?

I have an arc shapefile for a city which represents the rail road route. It is a single attribute arc that I would like to separate into segments of 90 ft. For example, if the standard track length ...
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0answers
159 views

How to measure orthogonal distance of line from point in QGIS?

As I am fairly new to QGIS I'm seeking your help. I'm trying to measure the distance between points in a point Layer P and the end of lines in a line layer L. In L there are two categories (attributes)...
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1answer
173 views

Get 3D length of line from contours (as attribute)

I have a road feature class (not currently Z enabled), and a contour feature class (which has elevations as an attribute). How can I generate the 3d length of roads as an attribute? Environment: ...
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1answer
186 views

Length of reversed geometry in meters

I know that a similar question has been asked multiple times here (a great answer can be found here: How can I get the geometry length in meters?), but in contrast I want to get the length of the ...
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1answer
816 views

Calculating Cumulative Distance (incorporating slope) of Line Feature Using ArcGIS for Desktop?

In ArcMap, when creating a line feature class within a geodatabase, the length of each record is automatically derived upon creation. This length is based on a distance measurement for a planar ...
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1answer
65 views

Are degree based length/area measures comparable across regions?

I have global shp files of basins (polygons) and rivers (lines). I wish to calculate a measure of stream length per basin area. It should be comparable across world regions, e.g. I wish to compare ...
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1answer
755 views

Splitting polygon features at specific widths using ArcGIS for Desktop?

I have a group of islands and I need to divide them into different segments based on feature width at several locations. There are four values for width (50m, 100m, 200m, and 300m) which I need to ...
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1answer
222 views

FME Segment Line with To/From Distance Values from Excel?

I have a large road network with some basic attributes like ROAD NAME, ROAD TYPE, LENGTH. Each road has been segmented but these segments are wrong for the new schema. I have successfully (mostly!) ...
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2answers
55 views

Wrong length of edges

I want to make a network analysis with ArcGIS. I am using openstreetmap-data from the Geofabrik but I have big problem: The length of my edges are not the right one. The length of the edge is for ...
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0answers
75 views

Loop distance point PyQGIS

I have a .shp of lines where I'm able to calculate the sum of segments length but I'm trying to put a point at a given distance in meters. The problem is it puts a point at every segment. When I give ...
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0answers
66 views

$length calculation anomaly

A polyline layer's (green) length is being calculated via $length. Result: ~100 meters (EPSG 31466). A buffer of 5meters is created and via Voronoi Polygons (and several other steps) a centerline is ...
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3answers
2k views

How to determine the length of a KML line tracing

I have a KML file which contains a line feature representing the passage of an Optical Fiber connecting two cities. I can trace them nicely in QGIS and OpenStreetMap. I would just like to know how I ...
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1answer
467 views

Arcpy - LayerList - Count/Length [closed]

I use arcpy to load all layers in the current map document, and I need all layers but not the last one (this is my layer for the symbology template). How can I access the length or count of the ...
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1answer
4k views

Get LineString length in meters (Python, GEODjango)

In a Django model, I have a LineString field which holds GPS coordinates of a street route. I know that I the .length holds the length of the LineString, but I don't know what unit the returned value ...
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1answer
834 views

PostGIS Get the POINT that is x meters away from a fixed point on the route (LINESTRING)

We have a route network stored in the routes table (LINESTRINGs). Basically every sedment (between two vertexes) is inserted as a separate row in this table. Among that we have a locations table (...
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3answers
3k views

Calculating slope length using LS-tool

Does anyone know how to get LS-tool mentioned in Zhang et al 2013. https://www.researchgate.net/publication/256938578_Extension_of_a_GIS_procedure_for_calculating_the_RUSLE_equation_LS_factor I tried ...
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1answer
580 views

Create a line from an array and measure its length with PostGIS (ST_MakeLine, ST_Length)

do I understand it correctly that it is possible to create a line out of an array with the function ST_MakeLine()? I would like to create a line from several points (more than two) and then calculate ...
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1answer
1k views

Store into a list multiple lists

I have list of 50 lists of pairs of SpatialLinesDataFrames. That means I have something like: [[1]] [,1] [,2] [,3] [1,] spldf1 spldf3 spldf5 [2,] spldf2 spldf4 spldf6 [[2]...
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1answer
487 views

QGIS polyline length calculation [closed]

I meet a problem while I try to calculate the length of a polyline in QGIS in the attribute table. I created a new column with the function "$length" inside (type: real, 10 digits and 3 digits of ...
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1answer
3k views

Calculating the length of the network lines inside polygon in QGIS 2.10.1

I am working with 2 datasets: delineations of the neighbourhoods traffic network. This is how they look: I would like to calculate the length of the roads per neighbourhood (polygon). As you may ...
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1answer
722 views

Deciding length of shapefile fields?

At my work have inherited several shapefiles that originate from MapInfo that I am bringing into a new project in QGIS. I have the opportunity to change the column names, add and subtract columns and ...
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0answers
65 views

Calculation of length in QGIS [duplicate]

I am trying to calculate the length of lines, which were convatede before from gps to Shapefile (vector layer). I tried it with "feldrechner" (matrix calculator?) and the most time I got 0, or in the ...
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1answer
488 views

How to get correct lengths when switching from GCS to PCS?

I'm working on ArcMap 10 and need to get the lenghts (in meters) of the segments composing my line feature class. GCS of the line is WGS_1984. Extent of this data should be: Left 11.236520 dd, Right ...
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0answers
2k views

Drawing features with specific dimensions in ArcGIS [closed]

I am having some issues drawing transect lines in ArcGIS. I need to create some lines that have specific lengths (20m and 30m). My Map units are set to 'meters' and coordinate system is NAD UTM 10. ...
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1answer
119 views

Clipping line feature to MANY polygons for measurements [closed]

I am looking to measure the length of stream segments(line) on numerous tax lot properties (Polygon). Is there a tool that will allow me to "Cut" or "Clip" streams to tax lots to estimate not only ...
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3answers
736 views

How to calculate path length of each point from the start using arcpy?

As shown in the picture below I would like to calculate the path length of each point from the start. Can anyone give me some help in writing this in python for ArcGIS?
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0answers
605 views

Deriving length values from GPX files in QGIS

I’m missing something real obvious and I apologize for revisiting a topic addressed in several Q&A’s here. I’m an experienced GIS user (not programmer) who’s new to QGIS (can’t afford Arc in ...
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1answer
2k views

Changing attribute length of existing field afterwards?

I already have about 100 values in a field in QGIS. I set it to 50 characters because I was thinking that would be enough. But that was wrong. I need more space in the column. But there is no way to ...
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1answer
944 views

Flow length analysis only shows pixel value, how to get length?

When I create a flow length analysis, and use identify tool on a cell in the layer, it just shows "stretched value" and "pixel value" I don't understand how it's supposed to show length. I'm using ...
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0answers
1k views

Length difference between Google Earth and ArcGIS for Desktop?

I have drawn a complex path with multiple vertices in Google Earth (GE) Pro and its measurement property is shown as being 2,460 nm. It is located East of Australia. If i import this KML into ArcGIS ...
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2answers
437 views

Separating polygons within layer and measure line through each polygon using ArcGIS Desktop?

I have 3 layers of polygons, each layer with multiple polygons spatially separated, although the layer only counts it as 1 polygon. I have a layer with a line going through these polygons. What is ...
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2answers
3k views

POSTGIS get the max length of the polygon and the average width

I have in postgis a polygon type table. I need to calculate automatically the maximum length of the polygon: And the second one is the average width: I am doubting rigth now if this is possible as ...
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0answers
95 views

QGIS (2.0.1): Field calculator for length not working - values way too high

Same problem as another thread: Field Calculator returning incorrect length and area values Trying to calculate length of a line shapefile, and field calculator is returning values that are way too ...
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0answers
436 views

How do I accurately measure a gps track over a long distance?

I am measuring the length of the Continental Divide Trail that goes from the Mexican border to the Canadian border. I have a .gpx file of the entire route in NAD83 with tracks about every 50 meters. I'...
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0answers
195 views

How to add column to attribute table using field calculator with $length function?

I used the following code to add a separate column to the attribute table with the length of features. from PyQt4.QtCore import QVariant from qgis.core import QgsField, QgsExpression, QgsFeature vl....
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2answers
132 views

Flow Mapper wrong line length calculation

I'm finding some trouble with the length calculation in the Flow Mapper plugin. As you can see in the picture below the length of the 2 lines C001-C021 = 4233.7986... C001-C009 = 6069.3053... is ...