Questions tagged [accuracy]
The degree of closeness of measurements of a quantity to that quantity's actual value
226 questions
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GPS Elephant Tracking II: Is ArcGIS basemap imagery orthorectified?
-- For my original question and pictures of elephants wearing GPS equipped anklets, go here. --
I'm experimenting with the use of GPS anklets to track the movement of zoo elephants. This has proved ...
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Getting best accuracy of coordinates for web GIS application?
I would like to develop my own web GIS application. It would be about some sport places in my hometown; it would be good practice for my education - I'm still a student. First, I need to get ...
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What is the maximum Theoretical accuracy of GPS?
I was talking with a potential client, and they requested that we plot some points with GPS, with a maximum (or should that be minimum?) accuracy of 2 m.
This is an area with no WAAS, and I was under ...
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CORINE LandCover: what about the accuracy?
How accurate is CLC? Do anyone know any scientific papers about that question? I tested the new CLC2006 for a region in turkey and its totally rubbish!
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ArcGIS Buffer accuracy problem?
Once again I encounter something very strange with ArcGIS. I perform a buffer analysis on one side of a polyline. There seems to be a serious accuracy problem and I can't figure out what the cause is. ...
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Calculating positional accuracy in QGIS?
How to you compare two layers in QGIS to get the positional accuracy?
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Need to learn more about Precision and Accuracy
I am currently taking Introduction to Image Interpretation online and there is a section in it that talks about Precision and Accuracy. I wanted to know if someone out there has any good information ...
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How much sense does it make to average (lat,lon) samples in order to increase 2D accuracy of a GPS location?
Several GPS applications, like this one, or this one, acquire multiple (lat,lon) samples of a given location, assuming that the GPS unit is not moving, and then take an average of the samples in order ...
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How accurate is approximating Earth as sphere?
What level of error do I encounter when approximating the earth as a sphere? Specifically, when dealing with the location of points and, for example, the great circle distances between them.
Are ...
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Probability of iOS/Android device location accuracy
I'm working with Android and iOS apps that report location. Both iOS and Android can derive location from a combination of cell tower triangulation, visible wifi access points, and assisted GPS. The ...
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Precision when working with spatial data in GIS
Is there a basic or introductory study that examines and compares the precision of spatial data when working
with varying precison of the data input, like having 1, 2, ... decimal places?
with the ...
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Tablet or smart phone GPS vs "real" GPS
I've been reading a lot today about android and iphone devices being used for spatial data collection in the field and it sure seems to be that single purpose devices such as the extremely popular ...
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Does a geotagged image contain information about its accuracy?
When I view my current location on Google Maps on my Android it shows me a circle of uncertainty. If I take a geotagged picture it will off course contain information about its Lat or Lon. Does it ...
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Which interpolation method is the most suitable for DEMs?
Which interpolation method is the best suitable for hill/valley areas and normal ground with undulations and rivers? When working with Aster 30mX30m DEMs, which method will give the most realistic ...
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How to store Large Raster Images of Equipotential Surface Generation Using Monte Carlo Simulation? [closed]
I have a large (1GB+) raster that I am using as the base for the generation of an equipotential surface. This is to assess the accuracy of DEMs derived from another source. In situ observation is ...
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GPS Elephant Tracking: Utilizing A-GPS, WAAS, DGPS and Understanding HDOP, NSAT, and ZDA
*I'm using a GPS data logger (qstarz bt-q1000xt) to track the movement of zoo elephants, and I have a variety of technical questions. I've had limited success receiving answers from the vendor. You ...
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how to calculate RMS 2D and RMS 1D, using python?
I would like to calculate:
RMS 2D: standard deviation for the two coordinates of flat (67% confidence level)
and
RMS 1D: standard deviation for height (67% confidence level)
What is the formula and ...
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Is city-supplied GIS data sufficient for transit operators or is own set of GIS data needed? [closed]
City GIS data is usually built in a format where streets/avenues/boulevards/etc are modeled as lines that are geographically located in the middle of the streets/avenues/boulevards/etc. Is that ...
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Accuracy of planimetric geometry vs. ellipsoidal model
I'm examining the two geospatial options for IBM's DB2 database. In particular I am interested in the accuracy between these two options and whether it's worth it (the more accurate representation isn'...
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Accuracy of measurements in Google Earth
Can anyone point to a resource that lists the accuracy of measurements taken in Google Earth?
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Generally accepted root mean square (RMS) error for rectifying topographic maps
This is a generic inquiry on the common practice/standard for determining the acceptable values of RMS when georeferencing topographic maps. Is there an absolute value?
Some literature suggests that ...
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Measuring accuracy of latitude and longitude
I have latitude and longitude as 19.0649070739746 and 73.1308670043945 respectively.
In this case, both coordinates are 13 decimal places long, but sometimes I also get coordinates that are 6 decimal ...
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What sample size should be used when applying the National Standard Spatial Data Accuracy (NSSDA)?
I'm less interested in what is recommended by FGDC, and more interested in information like this: SAMPLE SIZE AND CONFIDENCE WHEN APPLYING THE NSSDA, which suggests you need a sample of 100. Is there ...
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How correct is the "Accuracy" value given by GPS devices?
I have a Garmin Forerunner 305 and a Google Nexus One Android phone. From the GPS on both these devices I can get a "Accuracy" value that is usually between 6-20 meters. How much can I trust this ...
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How does ArcGIS compute the distance between two points with a non-equidistant projection?
This is a follow-up question to my previous one, Can you suggest some well-written introductory texts about coordinate system projections?
Let's assume I'm working with the CH1903 map projection, ...
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Is GPS more accurate on specific hours of the day?
I have heard that the GPS system is more accurate, and less accurate on some specific hours on the day.
If this is true, how can I get the information on when GPS is more or less accurate at my ...
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