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Questions tagged [measurements]

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

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1answer
48 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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14 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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20 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
90 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
71 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
15 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
72 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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60 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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280 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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19 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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15 views

Measurement tool and distance matrix function are giving different results on QGIS [duplicate]

I am using WGS 84 (maybe this is the problem) for both of my vector (point data) layers. Perhaps somebody could advise on what measurements are the most accurate? Do I need to use another Coordinate ...
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0answers
42 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
309 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
77 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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0answers
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
113 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
582 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
9k 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
88 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
164 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
96 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
38 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
64 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
186 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 ...
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1answer
299 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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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
163 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
565 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
231 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
69 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
355 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
59 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
52 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
871 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
80 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
271 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
252 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
220 views

Get nearest polygons in both sides of a polyline with arcpy

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
254 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
91 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
100 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 ...
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1answer
52 views

How is width commonly defined for areal features?

Map generalization guidelines, for instance applicable to CORINE Land Cover or Polish BDOO databases state inclusion criteria for areal features like "area should be > 250 000 m^2 and width should be >...
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1answer
78 views

GeoDjango -How to store measurement data

Assume I have recorded the following values during a bike trip. One such dataset has been recorded every 5 seconds: timestamp, longitute, latitude, pulse rate, pedal frequency What is the best way ...
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1answer
224 views

Advanced Digitizing Panel bad value or bug?

This is my first post here. What would cause the "Advanced digitizing panel" D (length) to show up wrong? I'm in the US using WGS 84 as CRS. If I add a feature (line) Advanced Digitizing Panels ...
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1answer
83 views

Measure building lean in ArcMap?

I was wondering if anyone is aware of any tools that are available to measure building lean in ortho images from within ArcMap. I am aware of calculations and processes that can be used to measure and ...
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1answer
150 views

Using measuring tool in ArcGIS

This is probably a very simple question - but opening up ArcGIS, the measure tool is unhighlighted, how do I make it so it is visible? Am I missing turning on an extension or something?
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2answers
578 views

How to determine objects area (size) measurement error using satellite images?

I am working at scientific paper about measuring object's size (it's area) using satellite images. I got some progress in it and need to compare my results with other scientific works. I have found ...