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Questions tagged [measurements]

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

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2 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 ...
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12 views

What is the accuracy and precision of bearings measured using Google Earth

For North America, what are the accuracy and precision that the bearings of decameter- to kilometer-long features, e.g lineaments and oriented lakes, be measured using Google Earth? Can these ...
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Handheld GPS accuracy precision [duplicate]

I wonder how any decimals place that considered reasonable for a handheld GPS accuracy? Can the accuracy of 3.897321 (6 decimals place) considered reasonable? Or does it has a limit? such as 3 ...
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1answer
42 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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22 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 ...
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1answer
23 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 ...
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1answer
86 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....
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1answer
82 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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25 views

Coordinate system of OpenDroneMap georeferenced PLY

I'm trying to work out the coordinate system of the georeferenced PLY from opendronemap. I have found a proj.txt file that contains the proj4 projection: +units=m +no_defs=True +datum=WGS84 +proj=utm ...
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21 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 ...
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1answer
92 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 ...
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1answer
148 views

Is it possible to change the measurement unit in QGIS 3.2 for the select features by radius tool?

Is it possible to set the default units for the select features by radius tool? I believe the default is set to meters but I can not seem to get it to use kilometers or miles for example. I know you ...
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1answer
20 views

Is there any difference in measurements when using the draw toolbar vs the editor toolbar?

Say I have a cornfield that I wish to measure acreage on. If I utilize the draw toolbar, create a polygon around the field, export to shapefile, add area field in attribute table, and calculate ...
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2answers
76 views

Measuring acreage from satellite image?

I am trying to use a ESRI basemap satellite image in order to obtain forest acreage values from a tax map parcel (image included). I have a parcel that contains farmland and forested areas, and I want ...
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88 views

Quick methods to make a shapefile/feature not m-aware?

Just wondering if anyone knows of a quick method to disable m-aware shapefiles/features? Searching Geonet, ArcDesktop help documents have proved unfruitful. I'm currently doing copy features and ...
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1answer
550 views

Creating Vector Buffers in QGIS 3

I am mapping the accessibility of job opportunities in Detroit for those who rely on public transportation. To do this, I need to create a circular buffer surrounding each bus stop with a radius ...
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24 views

Splitting a polyline at vertices and calculating start and end measurements for new features based on a known measurement of the original polyline

I have a route network which has a length-attribute defining length of each feature. This length-attribute comes from a data register outside of gis. Now I need to split each original feature at ...
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0answers
45 views

Calculate side of a polygon that touches another feature [duplicate]

How can I measure the length of the side of a polygon that touches another feature (calculate from A to B on the image below)? I'm creating and measuring lines to figure out the lenght of the '...
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1answer
377 views

Distance from one point to multiple points WITHIN a shapefile [duplicate]

I am looking to calculate the distance from a main point to multiple points WITHIN shapefile. In other words: I have a main point at the mouth of a creek. I have about 1,200 points at various ...
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1answer
98 views

Field sampling design: stratified random or transect?

I am trying to understand the impact of scientific activity in a remote polar environment. I have five locations in different parts of the region, where historic huts were placed for a couple of ...
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25 views

Measuring distance every 10 degrees

I have a point in the sea laguna and want to measure distance from the point to the closest shoreline within specified interval: every 10 degrees - new measurement. How can I do it automatically (...
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1answer
145 views

PostGIS Geometric V Geography measurements when using ST_Length

I was measuring geometry using some PostGIS functions and noticed that I was getting different results from the two methods I used. sum(st_length(st_transform(geom, 3857))) # Gave 3674 sum(st_length(...
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1answer
721 views

how to measure polygon perimeter / Distance in openlayers 3?

i am using openlayers 3 measurement tool for measuring line lengths and polygons areas, and this example worked for me: http://www.rhone-mediterranee.eaufrance.fr/milieux-aquatiques/poissons/js/...
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3answers
12k views

Measuring distance between points using QGIS?

I have a layer with about 500 single points. Now I want to measure the distance between each of these points and one specified observation point. I need the distance to show how far away from the ...
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1answer
98 views

Extract street right of way width from ROW polygon using street centerline

In the image below, I want to extract the width of each street's ROW, which would be twice the distance of each streets centerline to the nearest parcel boundary. Its slightly difficult to see, but ...
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1answer
218 views

How to calculate the mean distance between co-ordinates in QGIS

I have an assignment were I need to calculate the mean distance between coordinates. Effectively I am trying to find out what is the average distance in meters between buildings in a defined town ...
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1answer
101 views

Calculating change between two sets of district lines?

I'm using the Census Shape files for state legislative district lines for 2008 and 2012. I want to create a measure that indicates how much these lines have changed between these two time periods (...
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0answers
45 views

Running total of line length while drawing in ArcGIS for Desktop

Is there a way to display the running total length of a line while editing and drawing a new line in ArcGIS for desktop? I have a pdf with hand drawn lines representing hedgerows and the total ...
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1answer
1k views

Why is ellipsoidal distance greater than cartesian distance?

I created some linestring features in EPSG:32632 (WGS 84 / UTM zone 32N) exactly 10 000 m long. QGIS calculates all line lengths (horizontal, vertical, diagonal) as 10 001.9 m. The measure tool ...
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0answers
72 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-...
3
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1answer
231 views

Deactivate Snapping for Measure Maptool (mActionMeasure) in QGIS temporarily

I use the QGIS measure-tool to measure distances. I often would like to deactivate the snapping temporarily while using the measure-tool. Is it possible to deactivate snapping (for example with a ...
2
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1answer
374 views

QGIS, What is the reason for wrong scale and wrong areas? [closed]

I am currently working with QGIS and loaded openstreetmap as a basemap (web-> OpenLayers plugin), it is in WGS84/ Pseudo Mercator. For some reason the scale is not correct. For example a distance in ...
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0answers
30 views

Is there a measurement standard e.g. for coast lines? [closed]

When watching discovery & documentary shows, coastlines are apparently defined to be just long enough to fit some explanation or a discussed topic. The coastline paradox is a well-established ...
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1answer
199 views

Is the line color and thickness of the ArcGIS measure tool able to be customized?

Is the line color and thickness of the ArcGIS measure tool able to be customized? My searches have come up empty. \ I'm working against a dark background and the black line (from the measuring tool) ...
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1answer
608 views

How to calculate area correctly in QGIS?

I try to measure area in QGIS, but encounter some problems. The results seem to be quite inexact. When testing it with some administrative units (polygons from OpenStreetMap) and compare the results ...
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1answer
325 views

OpenLayers 3: keep sketch after measuring

I followed the official OpenLayers 3 Measure example to implement measuring in an application. It works fine, but when I finish my sketch by double-clicking it dissappears. In the following ...
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0answers
71 views

Large objects of fixed size that can be used for measure control points

I am looking for some real world objects that has rather large sizes where the exact size is known such they can be used for controlling different implementation of length measurements in GIS ...
3
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1answer
432 views

QgsDistanceArea.convertMeasurement not enough arguments error

I have setup a custom processing/python script to determine the shortest path on a network based on the code for Dijkstra's algorithm here, http://docs.qgis.org/testing/en/docs/...
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0answers
37 views

Buffer discrepancies

I have created a 1 km buffer around a polygon using Geoprocessing Tools in order to identify local sites which lie within 1 km. However, whilst one local site is showing as being within 1 km of my ...
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0answers
64 views

What latitude has equal land areas north and south? [closed]

There's obviously more land in the northern hemisphere than the southern, but at some point, there must be a line of latitude where the area of land above and below is exactly the same. Is it the ...
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0answers
59 views

Grass Gis r.viewshed how i can set max distance in meter or kilometer?

I have a problem with the r.viewshed max distance wiki: "The value entered is in the same units as the cell size of the raster. " Work: I get one geo file and where I run a viewshed with radius x(...
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1answer
996 views

Measurement accuracy for small distances - geodesic vs. planar UTM WGS84

Does anyone know how accurate geodesic measurement is compared to planar measurements in UTM WGS84 for distances below 15km? We'd like to inform our users about measurement accuracy when using tools ...
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1answer
84 views

Does height difference between beacons results in a more accurate 3D position localisation?

I'm kinda fresh on the trilateration/triangulation topic. If you place 4 beacons in each corner of a room at the same height or if you place them on different heights relative to each other will ...
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1answer
316 views

Measure polyline length in QGIS

I try to measure the length (in meters) of the polyline layer that pass inside the olive polygon layer only, and if it possible export the wanted polyline into new layer: the attribute table of the ...
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2answers
266 views

Measuring length through a polyline in QGIS.

I'm working on a fiber optic project. I want to measure the length through a fiber optic cable (polyline) from a point. Does anyone have an idea to help me? For example, I'm at the point 082 CTO and ...
3
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1answer
256 views

Getting nearest polygons in both sides of polyline with ArcPy? [closed]

I have polyline shapes representing roads and another shape layer with polygons that are representing buildings. I have to find some way with ArcPy to measure the distance from a point within the ...
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1answer
277 views

How to find cumulative length at points on a line?

I am working on a Modelbuilder project to teach myself how to use it. I do not yet have much knowledge in Python. I am currently a little stuck on the project I am working on. I have a line made from ...
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0answers
96 views

Measure the distance between points automatically

How can I measure the distance between points referring to the same element in an automated way? In fact I've imported in QGIS buildings downloaded from two different sources and obviously they are ...
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1answer
107 views

Discrepancy between constructed line length and length recorded in attribute table in ArcGIS for Desktop?

Say that in an edit session I create a line of an exact length entered by keyboard - say 10' If I later measure that line using the measure tool, snapping to each end of the line, it reads 9.99998' ...
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1answer
1k views

Measure distance between points along a line in QGIS

I have a road network and different points connected to the roads. I would like to measure the distance between several points along the roads. Basically I want to do the same like the road graph ...