Tagged Questions

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

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2
votes
0answers
47 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 ...
4
votes
1answer
116 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
41 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
74 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
0answers
380 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
129 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
20 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
65 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
575 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
102 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
142 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 ...
8
votes
1answer
324 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
103 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
346 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
136 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
32 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
2k 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
237 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 ...
2
votes
1answer
62 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
488 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
5k views

Correct way to create a DEM from point data in csv files

I know this might seem a somewhat general question, but I have to start somewhere. I have a lot of csv files which contain point data containing height, aspect and slope measurements at a resolution ...
89
votes
4answers
62k 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 ...