The closeness of a repeated set of observations of the same quantity to one another.

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2
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1answer
68 views

How to handle coordinates accuracy in ArcGIS

I am creating very basic rectangular polygon using very basic a Python code nCols,nRows=100,100 corners =[[0,0],[0,nRows],[nCols,nRows],[nCols,0],[0,0]] ...
1
vote
1answer
44 views

Is this distribution of GPS positions caused by multipath distortion?

I have some GPS points that are close to where they should be, but not nearly close enough (horizontal precision is around 10 meters). Looking at the positions which comprise these points (there are ...
2
votes
0answers
33 views

How to measure RTK accuracy of a moving vehicle?

I am currently working with tractors using a RTK enhanced automated steering system. One of the biggest problems is that even RTK can have a inaccuracy of 2cm. This can be too much for some possible ...
0
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0answers
35 views

Calculate coordinates with better precision in ArcGIS for Desktop?

I'm using the geometry calculator to get the geographic coordinates of a point shapefile. However when I run it, it calculates the coordinates with 4 decimal points, regardless I've chosen double an ...
0
votes
0answers
25 views

Objective comparison of different land cover data sets

One of the answers in this question Equivalent of CORINE land cover data sets for rest of world mentions the difficulty of comparing different land cover data sets such as CORINE and Global Land ...
3
votes
2answers
50 views

Compensating lat/long offsets after conversions

In my application I am doing conversions between two different formats of data. First format is a simple one containing NE and SW coordinates for a given rectangular area: area = { "sw": { ...
1
vote
1answer
67 views

PyQGIS export to JSON: writeAsVectorFormat and precision

In my QGIS plugin qgis2leaf I am exporting all layers as JSON into a JSON directory. Therefore I would like to enable the user to define the precision in the GUI. The normal "save as" dialogue in QGIS ...
2
votes
0answers
86 views

Row.Value returns rounded SHAPE.area and SHAPE.len values

I have created a VB.Net Add-In, and am using IRow to get the value of fields in tables in ArcMap to use in a query. But I am encountering a problem when getting the values of the SHAPE.area and ...
5
votes
1answer
241 views

What is the precision of a Geohash

I would like to know the precision of a geohash with a given length. If there is a 'simple' formula you can use to calculate it, that would be extra-cool. Wikipedia lists the precision up to 8 ...
0
votes
2answers
68 views

Densify a JTS LINESTRING (add points)

I have a LineString I would like to "soften" in a way that if two coordinates (vertices) in the LineString are very far apart, I want to automatically add some coordinates in between. The line ...
2
votes
1answer
275 views

How is Precise Point Positioning (PPP) exactly done?

I am looking for a positioning accuracy that is higher than normal consumer-grade GNSS receiver (mostly GPS/GLONASS hybrids with +- 5m precision). I came across RTK with dual receiver setup (base ...
5
votes
1answer
1k views

Cheapest centimeter accurate satellite positioning (GNSS/GPS)

I am looking for a cheapest possible GNSS/GPS setup with a centimeter precision without much HW hacking. I am not able to produce my PCB or do any soldering (though I would do that if there is no ...
2
votes
0answers
153 views

QGIS 2.4.0 Chugiak “reduced” real-type numbers. Precision problem? Bug?

I have a SHP point file created from CSV with QGIS 2.4.0 Chugiak. It contains some data on noise in a certain point. When I import from CSV, it seems to be fine, but when I export to SHP and open the ...
0
votes
0answers
23 views

calculation precision during projection transformation

I am using wgs 84 base tiles, and the tile is not rendered as image but with geojson format. I try to draw them in the tile according to the data. And the geometry of the returned feature is lng and ...
1
vote
1answer
75 views

Unable to select FLOAT precision when adding column

I'm trying to do the lessons in the training-manual at qgis.org. I,m having some problems with 3.3 Ratio Classification ...
5
votes
2answers
695 views

Accuracy vs Precision GPS

I am doing some research on consumer grade GPS accuracy and precision. I took 5 readings for 20 known locations (100 readings). Am I correct in assuming that the standard deviation between the 5 ...
1
vote
0answers
235 views

Precision for an FGDB raster dataset?

I would like to know the precision for an ArcGIS raster stored within a file geodatabase (FGDBR format); I can't seem to find this information anywhere in their documentation (apologies if I have ...
0
votes
1answer
287 views

How can I change the precision in the attribute table?

I'm working with QGIS, v. 2.0.1. I opened a csv-table (from an Excel-file) and now the precision is very high but I don't need this. At the moment the values are for example 15.00000000000000, how ...
9
votes
2answers
457 views

What is the precision of SELECT DISTINCT on PostGIS geometry column?

I wonder what the precision of the SELECT DISTINCT operator is on a PostGIS geometry. On my system, the following query gives me a count of 5, which means that the inserted points are considered equal ...
2
votes
1answer
110 views

What is a reasonable time to get a gps fix with 10 meters precision?

I hope I'm asking this at the right part of Stack Exchange. Please bear with me if I'm wrong. I'm developing some gps based applications. The demands I have for precision are not very high, but I ...
6
votes
3answers
413 views

Precision vs Resolution in elevation data

Update: A good example of my confusion: on the Wikipedia page for "digital terrain model" one can find the following statement about a satellite in the "See Also" section: TanDEM-X: generation of ...
2
votes
0answers
146 views

Spatial Precision for Editing in Multiple GIS Clients

I have something I'd like to discuss, I'll try to explain it first, why it's important, and I'll explain how ArcGIS handles the issue, which I think is a good way to handle it. Finally I'd like to ...
0
votes
0answers
34 views

A machine to measure latitude to 6 decimal places of a degree [duplicate]

I am doing a PhD research project to do with medieval and ancient archaeoastronomy which requires me to be able to measure latitudes up to an accuracy of 6 decimal places of a degree of latitude. ...
1
vote
3answers
3k views

How to auto fill or delete sliver polygons without losing precision?

I am developing some boundaries in which precision holds the key value. Using ArcGIS 9.3 I am converting lines to polygons using the "feature to polygon" tool. The lines are accurate but I find ...
4
votes
1answer
265 views

Display XY Format to Shapefile (Scale)

Using ArcView 10.1 and using excel for Lat/Long conversion to a shapefile. The original Lat/Long has 7 numerical characters past the decimal point xx.1143717. When I convert this excel into a ...
3
votes
1answer
81 views

What are arc's guarantees on data precision, XYTolerance (i) when displaying (ii) in arcpy?

Interesting behaviour: Two line segments in a dataset have almost, but not quite, identical endpoints. The difference between them is less than the XYTolerance for the data set. Reading the ...
6
votes
1answer
541 views

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 ...
6
votes
2answers
6k views

Creating DEM from point data in CSV files using ArcGIS Desktop?

I have a lot of csv files which contain point data containing height, aspect and slope measurements at a resolution of 12,5 meters. I need to create a dem from this data and have ArcGIS 10 with ...
100
votes
4answers
80k views

How to measure the accuracy of latitude and longitude?

I am very new to GPS stuff. Suppose 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 ...