Questions tagged [measurements]

Measurement is finding a number that shows the size or amount of something.

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1answer
43 views

Calculating distances between a set of coordinates

I'm using QGIS 3.2, WGS 84, EPSG 4326. I have a series of coordinates that represent the location of Red Squirrel trail cams in a Forest, there is another file with every sighting date and location ...
5
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2answers
117 views

Finding mean distance between cluster center and points in cluster in QGIS

I have done the following in QGIS: I used the integrated k-means clustering tool to cluster around 160k data points into 50 clusters. Using the mean coordinate tool (Vector analysis > Mean ...
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1answer
14 views

Will two GNSS modules displace by the same amount?

I am using two gps modules with blunos (bluetooth arduinos) too get the distance between them and display it on a phone. This has worked great and on avg Im getting the expected 5m inaccuracy. However ...
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1answer
95 views

Calculating length of each polygon side in PostGIS

In PostGIS, I want to calculate the length of different sides of a polygon. I know how to calculate a perimeter but how to calculate length side by side? Perimeter is as a sum of side's length so I ...
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5answers
488 views

Calculating polygon area in QGIS without adding new field

Is it possible in QGIS to quickly calculate the area of a polygon using a Processing tool, plugin, script without adding attributes or creating a new layer? Something launching the results window or ...
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0answers
109 views

Why ellipsoidal distance measured in EPSG:7030 in QGIS?

I measure distance (km) in QGIS (Ctrl+Shift+M) . In Ellipsoidal, it using CSR EPSG:7030. In Cartesian, they didn't say what projection is used. If it using ellipsoidal option, does it mean measured ...
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0answers
16 views

Can the Getis-Ord Statistic really be considered a measure of spatial autocorrelation?

The Getis-Ord statisic $G_i(*)= \Sigma_j w_{ij} x_j / \Sigma_j x_j$ basically calculates a geographically weighted average at some point. Is it fair to say that it is rather a measure of spatial ...
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0answers
24 views

Geodetically correct point spacing accounting for change in elevation

I am trying to create a grid of points at a specific spacing (30ft) for setting up a new orchard on fairly steep terrain. I have tried using "create fishnet" in ArcGIS pro. This is giving ...
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0answers
19 views

What is the accuracy of DMS coordinates that don't contain any seconds [duplicate]

For example, if I have coordinates for latitude 50°52'N, about how accurate are these coordinates? Within 10 km? 100 km? All the information I'm seeing is about decimal degrees, and I could convert ...
6
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1answer
73 views

Calculating distance between two points using QGIS C++ APIs

I have been trying to find the distance between two points using QGIS C++ APIs in Qt. I used the following code : QgsDistanceArea d; d.setEllipsoid("WGS84"); qDebug()<< "...
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2answers
384 views

Why accurate area of all countries cannot be obtained using a single EPSG code, even if it corresponds to an equal-area projection?

I would like to check if using different equal-area projections lead to near-identical area estimation for a list of countries. Importing modules: import numpy as np import geopandas as gpd import ...
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0answers
35 views

Required DLL for calculating distance between 2 points

I have been trying to find the distance between 2 points using QGIS C++ APIs in Qt. I used the following code : QgsDistanceArea d; d.setEllipsoid("WGS84"); qDebug()<< "...
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0answers
25 views

Calculate a straight or centerline of a polygon

I have drawn some roads as polygon and I wish to know if it is possible to calculate how long the roads are. I imagine that somehow QGIS can figure out the centerline of a polygon and create or ...
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0answers
22 views

Get layer information with Python module in Agisoft Metashape

I'm working on photogrammetry analysis and I want to improve my process. Recently, I saw that Agisoft has a Python module available and I could use it to automate my measure. I working on roofing ...
2
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1answer
166 views

QGIS CRS WGS 84 problem with the scale and measurement

I have a problem with my map scale. It shows 0:1 instead of proper scale. I am not capable to make any measurements, as the values go wrong. When I click on the measurement tool I get an error: This ...
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1answer
289 views

Measure distance in km of polyline in QGIS

As much as I have looked numerous times for how to measure vector polyline in QGIS I can not find the way. This seems like an easy thing to do but the answer eludes me. Dah! After I have traced out a ...
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0answers
62 views

Showing measurement in OpenLayers 6 while modifying

I have this code. I create class the name is MeasurementClass. this class used for overlays component creator, setting of html and configure style . this class can handle it. class ...
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2answers
63 views

QGIS v/s MapInfo - Differences in Distance Measurements

Distance calculated in different software (MapInfo and QGIS) has given me differences in distance values. To be more precise, it's mostly happening when the distance is more than 25 miles. I doubt ...
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4answers
168 views

Measuring distance between two points on curve line in QGIS

I am using QGIS 3.10 version. Image those two blue lines are points. How to measure the white line between those points?
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1answer
127 views

Measuring distance between two points using digital elevation model (DEM) and ArcMap

I have a number of points mapped on a digital elevation model (DEM). The points were mapped on the DEM based on their GPS location (latitude, longitude). What is the best way to measure the distance ...
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0answers
63 views

Getting more accurate area size using QGIS

I'm using Natural Earth's shapefiles and try to match them to the real area size. I'm utilizing $area expression, but no matter what ellipsoid measurement I use the result seems to be very off. For ...
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0answers
72 views

Advanced digitizing and measurement tool

I want to draw a polygon with 18m x 2m using the advanced digitizing tool. When I measure the size after creating with the measurement tool, the lengths of the sides do not match up (drawn sides vs ...
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0answers
38 views

Measurement tool of QGIS working in unsaved project but disabled in saved project

The measurement tool of QGIS 3.8 is working in the unsaved project but disabled in the saved project. I unable change the measurements or the units, and the Units dialog box is grayed out. However, ...
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0answers
108 views

Creating custom scale measurement for QGIS project

I started to make a map based on a raster (a scanned paper map). The map obviously has not geographic coordinates or a projection. The map comes with its own scale, and I would like to somehow make my ...
3
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2answers
80 views

Measuring distance between certain relations in QGIS

I need to measure the direct distance between busstops in meters, not taking roads/networks into account. I have the WGS 84 Coordinates + globalIDs for 28.000 pairs. I already imported the Busstops ...
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1answer
170 views

Getting accurate measurements in EPSG: 27700 using QGIS 3.10

When taking measurements in a project where all layers are EPSG:27700 (with elipsoid Airy 1830) the measurements produced are incorrect. Is there a better CRS for distance measurements in the UK? Or ...
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3answers
1k views

Finding length and width of regular/irregular polygons in QGIS [closed]

How can I find the length and width of regular and irregular polygons on QGIS? There's > 1000 so can't measure manually with the line tool. I have perimeter and area but need the other two ...
3
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1answer
300 views

Use "meters at scale" with custom CRS

[QGIS V.3.10.3 A Coruña] For streets in my fantasy world map I want to use a line ESRI shapefile. My custom CRS is a lonlat one and looks like the following: GEOGCRS["unknown", DATUM["unknown", ...
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1answer
42 views

On the fly/Dynamic measuring not working on Measurement Widget with different Basemap

I am developing an application with OS Open Carto Map as a Basemap and I have added a Measurement widget in the app. The measurement widget works fine for when the points are clicked for distance and ...
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1answer
118 views

Which map projection is suitable for distance measurement purpose in USA?

I'm developing an application which uses PostGIS functions for measurements in the USA. In nutshell: the software is running in a car and use PostGIS functions in real time. For example: to measure ...
2
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0answers
39 views

Measuring line input in attribute table

I'm using QGIS 3.10.0 A Coruna. I have a polygon layer (buildings) where I would like to measure each side depending on its geographic direction (north, east,...). I'm using the tool "Measure Line", ...
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0answers
69 views

Different distance when using "Measure Line" tool and manually with scale in QGIS 3

Using QGIS's "Measure Line" tool I get a distance of 1.22km between two points. But if I use the scale indicated at the bottom of the screen, 1:50000, and measure with a ruler, the distance is 2.5km (...
3
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1answer
176 views

QGIS under measuring distances

I want to create some transects and a grid with specific lengths, but I realized Qgis is under measuring distances. For the transects I used "Advanced digitizing" (100m lines) and for the grid I used "...
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1answer
259 views

Measure part length of polygon using QGIS

I have a polygon file of area boundaries and I want to measure part of the polygon lines in each area which next to the sea. Is there a way to do this? In theory I guess I could edit and make ...
2
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1answer
66 views

Projecting and Measurements

I am looking to project all my data into EPSG::2959 (NAD83 CSRS UTM 18N) as I am working out of Ontario, Canada. Every time I start a project I set the project CRS to EPSG:2959, and then begin to add ...
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0answers
88 views

QGIS wrong measurments on Google satellite images

I am new to QGIS but I understand the basic principles. I'm working with QGIS 3.8.3 on OpenSUSE Tumbleweed Linux using the KDE environment. Still trying to figure out QGIS, I'm opening a brand new ...
2
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1answer
107 views

Holding horizontal and vertical lines while measuring in QGIS

Is it possible to hold horizontal and vertical (similar to Ortho mode from Autocad) lines while using the measurement tool in QGIS?
2
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3answers
366 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 ...
2
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0answers
303 views

'Generate Points Along Line' Tool in ArcGIS Pro: Measured Distance Not Matching Up

I have a line feature that, when using 'Calculate Geometry' in ArcGIS Pro, shows me it is approximately 7,000 US feet long. I want to generate points every 10 feet on the line, and input that ...
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0answers
191 views

Distance in advanced digitizing not working properly?

I'm trying to remap a papermap of a festival with QGIS. I tried to use the advanced digitalizing tool to set the right distances and angles between the point but noticed that the distance I put in isn'...
1
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0answers
523 views

Calculating azimuth of direction in OpenLayers? [closed]

I am developing an application with OpenLayers and I need to calculate the angle between two segments or directions. I thought about getting the azimuth of those segments and then calculate the ...
1
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1answer
233 views

Difference between a GNSS receiver and GNSS antenna

I´m relative new using GNSS data and I would like to understand a little more about the instruments that I´m planning to use in my future research. I was looking information on the UNAVCO website ...
1
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1answer
217 views

Customized Albers Equal Area Conic projections are cosmetic only or do they affect area calculations too?

I will be doing area calculations for 100+ countries using country polygons taken from GADM, a database of global administrative areas. I am using ArcGIS. The GADM data is in WGS84 and is unprojected. ...
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0answers
40 views

Measuring distance traveled, in 3D using ArcGIS Pro?

I'm working in ArcGIS pro, I have tracking data from a bird's flight path and want to know how far the bird flew. I started with Google Earth KML Layer and imported to ArcGIS Pro. This layer has data ...
0
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1answer
68 views

Why measure line in QGIS result in millimeter?

I am using QGIS 3.4.4 I just want to measure the distance between a tree with its shadow from a raster data, but when i use measure line the result is in millimeter. I just upgrade the software to ...
1
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1answer
728 views

Get correct measurements for fantasy world map

I read lots of questions about fantasy maps and custom crs but none of the answers could solve my problems. Here is what I have: A planet with an equatorial circumference of 38 211 km (radius: 6081....
4
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1answer
626 views

How does $area function calculate area in QGIS?

I have a 550 meter by 550 meter square polygon in a shapefile. The QGIS 2.18 project and the shapefile both reference EPGS:32648 WGS84/UTM48N. EPGS:32648 uses meters as the units. When I use $area to ...
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1answer
426 views

What is the practical limit for lat/long measurement accuracy?

There are several systems for finding lat/long coordinates. This includes GPS satellites, DoD TRANSIT, Russian GLONASS, Galileo, differential GPS, LORAN, land-based systems, and more. Maybe even using ...
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0answers
31 views

What surface's area is used to compute area of country? [closed]

Premise: Earth's surface geometry is modelled by means of different geoids -depending on the objectives. The roughest and most basic are ellipsoids surfaces. Yet, on a small scale, e.g., area of ...
1
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1answer
105 views

How could you measure the minimum and maximum distance to the outer edge of a polygon in QGIS

I am looking for a automatic method to measure the minimum and maximum distance from a point (represented by the star) to the outer edge of a polygon (black dotted line). I know this could be done ...