Tagged Questions

An angular geographic coordinate that specifies the north-south position of a location.

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38
votes
2answers
18k 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. So now both co-ordinates are 13 decimal places long. But sometimes, I also get ...
29
votes
3answers
4k views

LatLon or LonLat, what's the “right” way to display coordinates and inputs?

I'm trying to get a sense if this is an issue for others or every input/output should be labeled so user is not confused and just go with it? I think almost everyone pronounces it as "LatLon". Who ...
19
votes
3answers
988 views

Why do we use the terms “longitude” and “latitude” for a spherical body?

To specify a geographic coordinate we use the terms “longitude” and “latitude”. Far as I know, these terms derive from the Latin latitudo (= breadth) and longitudo (= length). In German we use the ...
12
votes
2answers
384 views

How do you find a lat/lon (DMS) on a paper map using a 30cm ruler?

How do you use a 30cm ruler to find DMS on a paper map? The locations I would like to find are the 'corner' points so I can generate an extent based on the four corners. I have an old paper map (3 ...
11
votes
2answers
1k views

Why latitude/longitude and not the other way round?

When you google "latitude/longitude" you get 10 times more results than "longitude/latitude". This I find very confusing as "x/y" seems 20 times more common than "y/x". But on a map Latitude is on ...
10
votes
2answers
2k views

How do you compute the earth's radius at a given geodetic latitude?

(I see there is an equation on wikipedia that does exactly what I am asking but there is no references. I have no way of confirming the validity of this equation!) I already understand the difference ...
10
votes
2answers
1k views

Lon/lat transformation

First I should clarify I don't have previous experience with the field, so I don't know the technical terminology. My question is as follows: I have two weather datasets: The first one has the ...
9
votes
3answers
2k views

Computing an averaged latitude and longitude coordinates

How can I compute the average between several latitude and longitude spots ? Should I just compute the Arithmetic mean for both lat and lng ? thanks
8
votes
1answer
179 views

Great-circle lines in Equirectangular projection

Just to check that I'm on the right track: Are all great-circles on the sphere and in equirectangular projection (i.e. latitude, longitude pairs) either: meridians (i.e. going pole to pole) of the ...
8
votes
1answer
1k views

How to compute the bounding box of multiple layers in lat/long?

I am writing an application to performance test all kinds of map services, primarily AGS 9.x, AGS 10, and WMS 1.x. Part of the application involves generating random bounding boxes for individual ...
7
votes
2answers
459 views

How to get latitude /longitude in Degree Minute Second (DMS) using QGIS field calculator?

I have come up with the following expression to convert 5.1234 to 5° 7`24.24" toint ($x) || '° ' || toint((($x) - toint ($x)) * 60) ||'`' || substr( (tostring(((($x) - toint ($x)) * 60) - ...
6
votes
1answer
155 views

locating latitude-longitude point in a piste-map with matrix transforms

I am trying to plot points of a particular latitude longitude on this image of a Swiss mountainous landscape. What I am doing is I have some 54 known location-points plotted on this image (not ...
5
votes
2answers
1k views

Convert Long and Lat Co-ordinates to Square Miles

I have a set of Long and Lat co-ordinates making up a five point polygon which I have converted in excel using the following formula: ...
5
votes
2answers
289 views

What is the origin of the Degrees, Decimal Minutes format?

In my experience, for most non-GIS folks, the most commonly used and understood coordinate system is good old Latitude and Longitude, displayed as degrees, minutes, and seconds (DDMMSS.ss). In GIS, ...
5
votes
1answer
124 views

How do I georeference a ski map?

I have a map of a mountainous landscape, http://skimap.org/data/989/60/1218033025.jpg. It contains a number of known points, the lat-longs of which can be easily found out using google maps. I wish ...
5
votes
1answer
1k views

How can I render latitude-longitude coordinates on a map with D3?

I am trying to overlay dots of arbitrary sets of longitude-latitude coordinates on top of a United States map. So far I have found the D3 cartography example, but when I try to place dots on X,Y ...
5
votes
1answer
276 views

How can I programmatically open an OnPoint map to specific coordinates?

We have an OnPoint server at work and I'm wondering how to open the mapping service and having it zoom in to my specified latitude and longitude. The reason I ask is because we have an application at ...
4
votes
3answers
242 views

Canadian province boundaries in latitude and longitude

Are there any datasets available that give a list of latitude and longitude points for Canadian province boundaries? I don't need anything too detailed as I'm displaying collated data in smallish ...
4
votes
1answer
249 views

Problems with lat long projection

Hi this seems like it should be an easy problem, but its been giving me a headache. I have a .xls spreadsheet with about 60,000 rows. Most of them have Latitude and Longitude. I simply want to ...
4
votes
2answers
230 views

How to extract values from a raster according to Lat and long of the values?

having 12 files with 12 hdrs for one year: these files are raster (projected WGS84,lat long):https://echange-fichiers.inra.fr/get?k=rLSyoavrnifGyH5XrlO samples = 1440 lines ...
4
votes
1answer
33k views

Does Y mean latitude and X mean longitude in every GIS software?

Now it's been 3 days I am using Mapinfo and it has Y as latitude and X as longitude. Is that the same case for all mapping software? As for any country their respective value is multiple of 1 or -1. ...
4
votes
2answers
384 views

Converting Geocentric to Geodetic

I am only looking for a confirmation of what I believe to be true. If my explaination or conclusion is not accurate I would appreciate it if the reason can be explained to me. Background ...
4
votes
2answers
116 views

ST_Distance is not delivering right results

I want to calculate the distance between lat/lon points. I tried the following queries: Select ST_DISTANCE(ST_GeomFromText('POINT(-73.97923 40.75571)', 4326), ST_GeomFromText('POINT(-73.974509 ...
4
votes
1answer
96 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
3answers
153 views

How do I sort polygons by their latitude?

We have a set of polygons which we would like to sort and number according to their latitude. This will make it easier for local authorities to relate to the numbers of the objects. I have looked ...
3
votes
1answer
75 views

Which of these is the proper convention? [duplicate]

Possible Duplicate: Difference between lon and lng I run over these three abbreviations: "lat/lon" "lat/long" "lat/lng" Are they equal?
3
votes
2answers
255 views

Can one hide the Lat/Lng information sent to Google maps?

most services that use google maps have the Longitude / Latitude stored in the source to be sent to google maps to render their markers. However on this site (sorry Chinese) ...
3
votes
1answer
92 views

East North Format

I have a database with a list of address and their location as an East and North coordinate. An example is: East=431833 North=336684 Postcode=DE22 4LF When I try to convert this address using this ...
3
votes
2answers
586 views

How to calculate how long an arc second is for a given long/lat?

The title says it all, really. I am wondering what area is covered by a dataset which is one arc second wide. Thanks, Rob
2
votes
3answers
116 views

What Danish position format is this?

I have been given a list of locations within Denmark. Most of the are in decimal degrees. However, some of the positions are in different formats and I can't figure them out. Does anyone recognize ...
2
votes
2answers
1k views

Problem when calculating longitude and latitude for points

I have a PostGIS database with SRID=900913 (Google Mercator) and I would like to know the latitude and longitude of points. I use this command: ST_X(ST_TRANSFORM(the_geom,4283)) Following what is ...
2
votes
2answers
235 views

How to avoid exceeding latitude and longitude limits, when importing a .csv file?

I am currently working with a project with "on the fly"-projection (WGS 84 / UTM zone 32U). Now I want to import a csv. file with points, which have a longitude and latitude using the "Add Delimited ...
2
votes
1answer
218 views

WGS84 - how to convert

I have multiple locations saved in WGS84 - it looks like e.g. latitude: 12345678 longitude: 87654321. I tried to search it on the map this way: 12.345678 87.654321, but it doesn't match the place it ...
2
votes
1answer
237 views

How can I get the corners of a polygon in latitude and longitude?

How can I get the corners of a polygon -a square/rectangle, to be precise- in latitude-longitude format by using its geom value -or some other way, perhaps-? Thanks.
2
votes
2answers
267 views

Getting zone from UTM in order to convert to latlong

I am trying to convert UTM to a latlong point. To get that done I need to know the zone where the UTM coordinates are. how can I find the zone from UTM?. the place coordinates that I work on lay on ...
2
votes
3answers
1k views

How to convert geometry coordinates into Google lat/lons?

For storing geospatial data, the geometry field is used in SQL Server or Oracle Spatial. I want to know is there any way where we can convert this geometry field into a set of latitudes and ...
2
votes
2answers
484 views

Creating Latitude Grid from DEM

I am trying to evaluate an equation in the raster calculator and I need latitude values. I have the DEM for the region and am wondering if it is possible to create a latitude raster based on the DEM? ...
2
votes
3answers
186 views

Looking for a fine U.S. Latitude and Longitude grid (0.25, 0.5 degree)

There is a global latitude and longitude grid data available at 1 degree resolution and higher (http://www.arcgis.com/home/item.html?id=f11bcdc5d484400fa926dcce68de3df7). Is anyone aware of a finer ...
2
votes
1answer
70 views

Representing degrees between -1 and 0 in Degrees:Minutes:Seconds

When representing latitude and longitude in degrees, minutes and seconds, with -180 <= D <= 180 (or -90 and 90) 0 <= M < 60 (0 if D is at an extreme) 0 <= S < 60 (0 if D is at an ...
2
votes
1answer
70 views

Need software to read geo information from tif

I am trying to verify the lat/lon and ECEF values that I have determined for a very specific and unusual situation (a geotif file), and it would be great if I could find some software to read them. ...
2
votes
3answers
1k views

Income data on a block level: how does a newbie do it?

I am a complete newbie at GIS data, and am trying to do the following: Figure out census blocks in Miami-Dade (and several other counties) that have average household incomes > $75,000 Get the ...
2
votes
1answer
136 views

Trilateration 3D - Vincenty's Formula

with reference to Trilateration using 3 latitude and longitude points, and 3 distances. The accepted answer was votes as shown in wikipedia at: http://en.wikipedia.org/wiki/Trilateration in ...
2
votes
1answer
180 views

How to georeference using Latitude and longitude in QGIS?

I'm trying to georeference a picture using Latitude and longitude. The points are these: top-left: (116.30950927734372,39.970805680527725) top-right: (116.35620117187497,39.970805680527725) ...
2
votes
1answer
395 views

How to determine maxResolution and numZoomLevels in dynamic environment?

I want to determine resolution and number of zoom level dynamically instead of inputting the values in openlayers client. When the user move the position on map by dragging or panning control, I can ...
2
votes
0answers
120 views

calculating bounding box from known centre coordinate and zoom

I have a map, the centre of that map (centrepoint) is = -37,175 ( gps) I know the zoom of the map = 13 I know the size = 320x320px I know there is 111111m in a degree of latitude and a varying degree ...
2
votes
0answers
94 views

how to convert lat and longitude into distance near poles?

I am trying to convert latitude and longitude into meters in polar regions. I am looking for higher accuracy upto 0.00 meters preferably. I tried the haversine formula but it doesnt seem to be ...
2
votes
0answers
197 views

Convert Lat/Long to UTM specifying which zone to use (Java)

I have a set of coordinates in decimal degrees spread across two UTM zones in my Java application that I want to export to use in Petrel, so they need to be in the same UTM zone. Is there a java ...
2
votes
1answer
529 views

Plotting latitude on to a (Mercator projection) SVG representing a country map

I want to convert (google sourced) longitude and latitude coordinates to x and y to place points on a SVG map I can get the longitude converted to X but I can't nail latitude. ...
1
vote
2answers
732 views

shape file coordinate system

I added a shape file of Iran to Qgis. 'Tehran' has 35.6833° N, 51.4167° E coordiantes, however Qgis shows Tehran with 4772860,31296767. How i can view coordinates of a city or location in latitude ...
1
vote
1answer
203 views

Converting a shp file to a list of latitudes and longitudes

I have a shp file with the latitudes and longitudes for the boundaries for various geographic regions. I'd like to convert the shp file into lists of just latitudes and longitudes for the regions. ...

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