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Questions tagged [length]

The longest extent of anything as measured from end to end

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votes
1answer
36 views

Computing total road length in fixed radius circle around a point

I have a dataset of a number of points which are plotted on QGIS using their latitude and longitude. Now, I have to find out the total length of roads surrounding each point within a circle of radius, ...
5
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2answers
115 views

Different length measures in QGIS vs. ArcMap

I noticed that QGIS and ArcMap return slightly different length measures when calculating geometries (length) on one and the same shapefile (see image). In QGIS I used the $length command, in ArcMap ...
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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 ...
3
votes
1answer
188 views

Different results using $length (field calculator) in QGIS versions 2.18 and 3.0

I use the field calculator to measure the length of LineStrings in my shapefile layer, but i get different results when using QGIS 2.18 or QGIS 3.0. If I am using the local coordinate system the ...
2
votes
1answer
38 views

Adding $length on the fly when adding line feature

is there a simple way (without writing script or python skills) to auto calculate and auto populate length attribute in QGIS? When I add a new line feature in my layer, I'd like the attribute length ...
8
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4answers
212 views

Calculating polygon's length along a line?

I need to calculate the length of polygons along / projected on a line. An image to show the idea: I have thousands of polygons to be "projected" on lines to verify how many meters of the line they ...
2
votes
3answers
66 views

Finding accurate distance of a drawing in QGIS

Attached shows a rough drawn image of a pipeline track. I need to measure the pipeline track from one end to the other, e.g from the red and blue square to the other red and blue square, e.g from the ...
13
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4answers
16k views

Getting geometry length in meters?

In PostGIS, the ST_length() function returns the length of a linestring in some units, but not in meters. Is there a function like ST_Length() but in meters?
1
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1answer
49 views

Calculating the length of a single edge in QGIS

I need the correct length of a edge between to points(yellow line in the picture below) in the unit [m] for validation of an equation. I just found the possbility to add geometry (length) to the ...
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0answers
62 views

SumLineLengths in QGIS 3.2 not working?

I'm trying to use the Vector > Analysis Tools > Sum Line Lengths in QGIS version 3.2.3-Bonn. I'm inputting a ploygon (Multi Polygon) and a Lines (MultiLineString) shape files. I'm hoping to get the ...
3
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0answers
53 views

Lines length plugin - QgsVectorLayer error

Several similar questions have already been made, but none of the is helping me. I have a layer of polygons and I want to known the length of each line of each polygon. And based on the length I ...
13
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4answers
4k views

Looking for a pythonic way to calculate the length of a WKT linestring

I was quite unsatisfied with Calculating Length of Linestrings in WGS84 in Miles. It kept me wondering if there is a more convenient, Pythonic way to calculate the length of a WKT linestring according ...
1
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1answer
49 views

Which coordinate system/ projection would you use to measure lines globally distributed?

Which geographic coordinate system /projection would you recommend to measure the length of hundreds of lines which are globally distributed (southern and northern hemisphere)? The lines have a length ...
0
votes
1answer
80 views

Determining percentage of overlapping lines using QGIS?

i have a lines layer that represents the bikeways of my city, and also have another overlapping layer that represents the bikeways that need repairs. How can i get an analysis of the percentage or ...
1
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2answers
71 views

Measuring width of polygons, which is wider than long

Within my project I am trying to quantify and compare different submarine landslides with ArcGIS. Therefore, I created a polygon shapefile and mapped the spatial extent of each landslide. Now I want ...
2
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0answers
104 views

Calculate length of selected features in PyQGIS

I create a selection with getFeatures(QgsFeatureRequest()) and I want to calculate the length of the result which is a QgsFeatureIterator : select = QgsExpression(" myexpression ") selectedfeats = ...
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0answers
19 views

QGis 3.4.4 xyz-dependend height length calculation

We use $length to display the length of our lines. The outputs are only xy calculated We need to calculate with the height reference system DHHN 92 to get the true xyz lengths. How do I set up the ...
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0answers
27 views

QGIS KML lengths appear to be wrong? [duplicate]

Every time I import a KML into QGIS the line lengths are wrong. A line that was 191 ft on Google Earth is now 260 feet in QGIS. How can I solve this problem?
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1answer
106 views

QGiS 3.0: Line length without overlapping parts

I have overlapping lines in my layer and want a total length of the visible line without the overlapping part. i.e. I have two lines First one goes A-B-C Second one is B-C-D How do I get the ...
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0answers
31 views

Calculating route length per grid cell using fishnet

I have a problem determining the length of the routes (boat) I've surveyed in order to calculate the survey effort. I added the GPS points of the boat and then used the points to line tool and added a ...
4
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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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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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0answers
139 views

Attributing polygons based on line attributes

I'm using QGIS 2.18. I have a grid that I need to calculate Azimuth and length for each side. Most have 4 sides but some ( see Gird C below) many more , up to 12. My process now convert Polygon to ...
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1answer
937 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 ...
1
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1answer
60 views

Maximum Length parallel line

I have a polygon and I want to make parallel lines inside of the polygon. I need to have the maximum length when I sum the length of all of them. Each line must be 15 m apart.
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0answers
79 views

QGIS - Parallel Lines - Count length of one

I have a large layer of lines (telecommunication duct) with in parts several parallel lines that are close to each other (cause they lay in the same trench). I would like to count the length of the ...
2
votes
1answer
132 views

Is there a way to calculate length of linestring from one point to another?

If I have one linestring and coordinates of two points on that linestring, what is the easiest way to calculate not shortest distance from those two points, but distance over the given road (given ...
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0answers
17 views

Calculating length of line using British National Grid projection? [duplicate]

I need to calculate the length of a line in (KM) in QGIS using the British National Grid as the Projection. Can somebody explain to me how to do this?
1
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1answer
841 views

Calculating length of polygon in ArcGIS Desktop?

I am using ArcGIS 10.2.1 Desktop with an Advanced license. My company has electric lines that go through people's yards. The areas around these lines require trimming occasionally, which necessitates ...
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0answers
144 views

Changing Virtual field properties in QGis 3.0

I have some existing virtual field with set Length and Precision An example: The formula was first set to rounding it by 2 digits With the current settings it displays 10.00 instead of 10 because of ...
3
votes
4answers
395 views

Calculate length of huge vector lines dataset

I have a MultiLineString vector layer from which I would like to calculate the length. I have tried to calculate the length with the Field Calculator by putting in the expression $length. The ...
3
votes
0answers
292 views

Wrong length values on QGIS 3.0.3 and 3.2

While using QGIS 3.x today I noticed that length values were not calculated and measured correctly on EPSG:32611. Calculating and measuring the same data on QGIS 2.18 latest LTR and 2.2 on EPSG:32611 ...
2
votes
1answer
241 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 ...
1
vote
1answer
114 views

$Length-attribute output

I created a layer to visualize cable-laying and want to export the sum of the cable-lengths to an excel file when I'm done so i created an attribute for it. How do I link an attribute to the auto-...
1
vote
1answer
468 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 ...
1
vote
1answer
631 views

Calculate length of Multilinestrings/Linestrings/Polygons in geoJSON file

I have a couple of routes on my map where I would like to display the length of each route. I think I've found what I was looking for here: https://github.com/tyrasd/geojson-length, but I'm not sure ...
2
votes
1answer
378 views

Longest flow path in QGIS from single feature vector

I have got a vector layer with one feature (MultiLineString) representing a river network (s. below) without bifurcations. In addition there is a point shapefile containing the outlets of different ...
2
votes
1answer
243 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 , ...
1
vote
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 ...
1
vote
2answers
96 views

Calculate perimeter of a large polygon using geodesic calculations

How do I calculate perimeter of a large vector polygon (polygon set) which spans almost half the globe? I guess regular calculations do not produce accurate results in this case.
1
vote
1answer
59 views

ST_Intersection preserving overlapping edges

I have a linestring that represents a bus route, and includes some overlapping sections where the bus has traveled back on the same street. When I ST_UnaryUnion the line, or ST_Intersection it with ...
0
votes
1answer
170 views

Buffering multiple feature classes from dataset based on length using ArcPy?

I am a beginner at Python and for my current project I am expected to list all polyline feature classes within a dataset, find the length, and then perform a buffer analysis based on it's length. This ...
2
votes
2answers
163 views

Choosing CRS for metric distance calculations? [closed]

I have the following ArcPy script to calculate total length of Polylines in a Feature Class/Shapefile: arcpy.Project_management('lines.shp', 'lines_projected.shp', arcpy.SpatialReference(TODO EPSG ...
0
votes
1answer
277 views

Calculate river distance to headwater for every pixel?

I already posted a similar question a few weeks before. But since my dataset changed and I still havent solved it, I thought its good to post a new question instead of editing the old. Using ArcGIS ...
3
votes
1answer
2k views

How to convert length in Decimal degrees to meters programmatically?

I'm new to qgis and I want to find the length of some roads in a map. So I used the following code, from shapely.wkb import loads def getLength(): layer = qgis.utils.iface.mapCanvas().currentLayer()...
2
votes
1answer
58 views

Calculate common length of two lines using ArcGIS Desktop?

I have a shapefile that consists of around 800 different lines. Now i have another shapefile which also consists line data. Is there a method which can help me calculate the shared length in the ...
2
votes
1answer
158 views

Difference in lengh calculations for ESPG:32632 and ESPG:4326

I have a shapefile with CRS ESPG:32632 where are shown some power lines of a ​​northern Italy area. I need to calculate the length of the lines and add it, as a new field, in the attribute table. I ...
1
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0answers
189 views

r.flow in QGIS 2.16.1 generates wrong output

I try to run the r.flow module to get the flow path length of my layer out. The input Layer is a DEM with pixelsize 0.0083 and the selected CRS (EPSG:32646, WGS 84/ UTM zone 46). First of all I ...
0
votes
2answers
117 views

Tracing or snapping to polygon border for measure tool

I am trying to do a simple measure of the length of seperate sides of a polygon depending on which other polygons it borders (in the image: the dark blue borders of the green polygon to the white area ...
1
vote
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]...