A reference framework consisting of a set of points, lines, and/or surfaces, and a set of rules, used to define the positions of points in space in either two or three dimensions.

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2
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1answer
638 views

How to speed up this simple MySQL points in the box query

MySQL doesn't have nearest neighbor search so. So I try to come up with a "distance" that's reasonable so the number of returned query is around 20-200. That way innodb doesn't have to compute ...
2
votes
2answers
473 views

What does 1:10m mean related to map resolution?

On Natural Earth they offer maps at various resolutions. What does 1:10,000,000 mean? Does it translate to the number of points per square meter or mile?
2
votes
5answers
2k views

Convert geographic coordinates to UTM zone 29N with Javascript

I have an issue converting lat longs to UTM with the ArcGIS javscript API. Lets say that I have a map, based on the UTM zone 29N, also known as WKID 32629. I have a known set of coordinates from a ...
1
vote
1answer
207 views

Help defining custom CRS in QGIS 2.2

I'm trying to use EPSG:4479 in QGIS. 1) If I search for EPSG:4479, it returns a "Imported from GDAL" EPSG:4479, but it does not work. At the console, the following message is displayed: ERROR 6: ...
1
vote
1answer
213 views

How do I create an index layer for multiple maps?

I am trying to create an index layer of just the area within the Orange lines. I am having difficulty creating this layer due to it not being a simple box area. The goal is to create a index layer, ...
0
votes
2answers
140 views

Calculate length of line across zones with at least m accuracy

I have created lines between multiple points that are across MGA 54 and 55S (EPSG 28355). I am trying to calculate the distance between points but different methods give different answers (~1km ...
0
votes
1answer
700 views

How to calculate the UTM-Latitude-band?

I have to convert a coordinate from UTM to MGRS. I think I have the most of it covered, but I have some difficulties to calculate the correct Latitude-band. How can I decide which band the coordinate ...
20
votes
3answers
2k views

What was the rationale for the non-standard UTM zones near Norway?

UTM zones 30V, 31V, 32V, 31X, 33X, 35X, and 37X do not line up with the rest of the UTM zone grid. Why was this allowed? According to Wikipedia, UTM was developed by the U.S. Army Corps of ...
8
votes
1answer
4k views

getExtent() in OpenLayers returns strange values

I'm trying to get the bounding box of the map area displayed by OpenLayers. I tried to use map.getExtent() because it should be exactly what I need, but the returned values are "strange": For ...
6
votes
2answers
1k views

Why do my Shapefiles not align correctly?

First: I'll summarize what I understand so far so please confirm or correct me. When On-the-Fly is selected a layer is re-projected from that of the layer's CRS to that of the project CRS, IF ...
5
votes
2answers
537 views

Identify what projection this Australian map uses?

Im looking to put this map into google maps as custom tiles, but i now learn what projection is and that this map does not use the same format as google's default. You can create custom projections i ...
5
votes
1answer
1k views

How do I find the intersections of 2 circles on earths surface?

I have the circles' center in lat & long, as well as the radius in meters. How do I find the circles intersections? Edit: EXAMPLE: Circle 1: Center on Earth's surface (43.564627,-116.220524) ...
5
votes
7answers
1k views

Problem with Swiss coordinate system overlay in WMS

I have administrative boundaries data for communities in Switzerland from SwissTopo. Original data came in shape files with 'Bessel 1841 Hotine Oblique Mercator Azimuth Natural Origin' projection. ...
4
votes
3answers
436 views

Does the NED use geocentric or geodetic latitude?

What kind of latitude does the National Elevation Dataset (NED) use? Geocentric or geodetic or something else? I can't find the information anywhere on their site (http://ned.usgs.gov/index.html) or ...
4
votes
2answers
13k views

Convert X,Y State Plane coordinates to decimal degrees

I have 1000's of data point I need to convert from North Central Texas 4202 into Lat/Long decimal degrees. Can someone give me a conversion equation so I can quickly convert using excel? I have only ...
4
votes
0answers
285 views

Can GeoTools parse GML CRS definitions?

A kind of branching of this question. Soon I will need to handle GML Coordinate Reference Sysyem definitions in a Java servlet. Links: GML OGC reference. Concrete example. I know that GeoTools ...
4
votes
2answers
429 views

How to efficiently project datasets of varying coordinate systems into one coordinate system?

I am working on streamlining data processing at my organization. Currently we are using various large-scale Models that we will gradually bring into Python. The gist of our data processing is as ...
4
votes
3answers
577 views

Defining the appropriate Projected Coordinate System

I am a beginner at ArcGIS and have a technical question. I need to assign a projected coordinate system to my boundary/polygon data in order to calculate square miles. There are many to choose from. ...
3
votes
1answer
48 views

USA Contiguous Albers Equal Area Conic to miles

My data is in USA Contiguous Albers Equal Area Conic projection. How can I convert the USA Contiguous Albers Equal Area Conic projection to miles?
3
votes
1answer
96 views

methods for converting coordinate datum and format in python?

Related to an earlier Q&A of Missing grid shift files for cs2cs.exe? ... what are the various methods to convert coordinate datum and format in python? (Windows Vista, python 3.4) For example, ...
3
votes
2answers
60 views

Digital Elevation Model and Shapefile not aligned in openWind

I have a digital elevation model and a shapefile containing point features for the location of wind turbines. These two layers appear to be aligned in QGIS but when I open them in openWind, they are ...
3
votes
1answer
234 views

How to properly open an ASTER data?

Yesterday i downloaded an Aster L1B image from USGS's website. If i load it in QGIS, it doesn't get displayed properly(location wise). Even after i've enabled "On the fly" option, it's not reading the ...
3
votes
2answers
1k views

Where is list of Geographic Transformations in ArcGIS, and their areas of applicability?

I have some data in Provisional South American Datum 1956, and I need to project it to Web Mercator with WGS84 as the datum. When I use the project tool in ArcGIS desktop, it requires a Geographic ...
3
votes
1answer
994 views

getting the specified geographic transformation, or at least the GCS, of a data frame

First, the TLDR digest: I'm getting a bogus value from dataFrame.geographicTransformations on some machines; how do I get the correct value as shown in the properties dialog? and/or Given a spatial ...
3
votes
1answer
3k views

Converting geographic coordinate system in R

I have points in geographic coordinate system and I wanted to convert them to swiss grid (CH1903+). Sample data: id lon lat 2 7.173500 45.86880 3 7.172540 45.86887 4 7.171636 ...
3
votes
1answer
620 views

QGIS custom CRS for map of manufacturing shop floor

I'm working on a web app that shows a map of a manufacturing plant's shop floor. I've built it in Inkscape and QGIS, but when I try to load it into Tilemill, I get a CRS error. Specifically, it ...
3
votes
2answers
368 views

How do you change the prime meridian of a map?

I am working with the Natural Earth world map as a SHP file, but when I try to change the prime meridian (PRIMEM) of the coordinate system ...
3
votes
1answer
3k views

How to get the coordinate system from a PostGIS database?

My question is probably amazinlgy stupid, but I can't find the answer myself. I would like to extract from a database the latitude and longitude of points. For now, I'm getting x(the_geom) and ...
3
votes
1answer
487 views

Why are the formats of these coordinates different?

I'm really sorry if this is a silly question (and I'm sure it is) but I have tried searching but I am a complete newbie to coordinates and maps and I don't know what I'm looking for so am not finding ...
2
votes
0answers
74 views

QGIS 2.8 Raster Layers Moved [duplicate]

I recently downloaded QGIS 2.8 and opened an existing project in it to check how it handled it and make any changes required. This project includes several raster heatmap layers. My problem is that ...
2
votes
1answer
57 views

PostGIS GML round trip confusion

I've investigated the issue of coordinate order in GML and each time I think I've got it but I find my self confused once again. I think some of my confusion may be to do with PostGIS. Doing a ...
2
votes
1answer
146 views

Dealing with raster: creating it in projected CRS and exporting it in geographic CRS

When creating a raster from a polygon (the CRS of the polygon is a geographic coordinate system), the raster is created in the projected coordinate reference system of the data frame, which is a ...
2
votes
1answer
159 views

How to find the projection of an image?

Instead of georeferencing the image and deforming it, I'm trying to find the projection used by the author of the image. I've got tens of these distribution maps to digitize. The idea is to avoid ...
2
votes
2answers
148 views

which map projection should be used for global map with geography and human demographics

I am working on a project to try to identify the most threatened populations (on a global scale) of having a limited access to freshwater. I want to compare those most at risk currently and then add ...
2
votes
1answer
184 views

Why is shapefile not drawing in expected location after (or before) using Define Projection tool? [duplicate]

I have downloaded this zipped shapefile of bus routes from the City of Houston data portal. I then performed these steps in ArcGIS Desktop 9.3.1: Extracted the shapefile from the *.zip Added this ...
2
votes
1answer
129 views

Can you create a CRS of superseded NSW Datum

I want to use a superseded projection (NSW integrated survey datum - referred to as ISG) because my main client utilises it. The projection is based on AGD66. We regularly receive survey files in this ...
2
votes
3answers
278 views

Geodesic measurements for short distances throughout US?

My ArcGIS experience has been limited to working on large-scale maps with planar projections. I'm moving to a project in which I want to calculate the distance between pro sports facilities throughout ...
2
votes
5answers
496 views

Is latitude / longitude a universal coordinate system?

I hear people complain: my biggest gripe with google spatial apis is that they hide the fact that latitude/longitude is not a universal coord system My question is Is latitude / longitude a ...
2
votes
1answer
155 views

How do I set the projection and coordinate system for a TIFF file?

I have a topographic map of California (obtained from CAL-Atlas) as a TIFF file. I tried importing it into QGis, but it displays the map using a pixel based coordinate system rather than ...
2
votes
1answer
120 views

Problem converting coordinates

I'm trying to convert punctual values from lat/long to EPSG:6372, a projection for Mexico, defined by the Instituto Nacional de Estadística y Geografía (INEGI). I found a converter online but somehow ...
2
votes
1answer
115 views

Why does same image in two ArcGIS ArcMap configurations show different extent numbers?

I would like to get hear from you about the situation I am seeing here. What It got my eye was that when I download an ASTER from Reverb/ Echo from USGS website. At work, I load my ASTER file to my ...
2
votes
1answer
510 views

How to align (georeference) images using QGIS?

I'm completely new to all this. I'm trying to make a map of Han dynasty-era China for a mod for a game called Crusader Kings 2. I've downloaded QGIS and Natural Earth 2, but I need this image to ...
2
votes
1answer
168 views

Why does QGIS 1.8.0 crash when I try to set up CRS on Win XP?

I have a problem with my qgis 1.8.0. When I click on any button that set CRS or try to set the coordinates on the fly, qgis crash. I try to uninstall the program and re-install it again using ...
2
votes
1answer
168 views

Setting coordinate systems in QGIS: “transform error caught”

I'm learning how to use QGIS (v 1.8.0 "Lisboa") on Mac OS 10.6.8. My goal is to create a simple county map of Illinois using the base data shapefiles available from the Illinois Natural Resources ...
2
votes
1answer
488 views

Is it possible to convert data from WGS84 to Bessel1841?

When we convert data from bessel1841 to WGS84, parameter setting must be used because it is impossible automatic convert on QGIS. Reference: Converting shp file from bessel1841 to WGS84 Is it ...
2
votes
1answer
299 views

Problems with NAD27 projection in QGIS

I have some data that is in NAD27, but I am having a hard time displaying it in QGIS. I think that the problem is with the CRS. I cannot seem to find the correct NAD27 option. The closest one seems ...
2
votes
1answer
958 views

Reprojection from WGS to Slovenian Gauss Kruger in QGIS

I have gpx file (track) in WGS84 (EPSG: 4326) coordinate system from Garmin GPSMAP 62 which is right projected in BaseCamp and MapSource. When I save track as *.GPX and import it to QGIS and use ...
2
votes
1answer
312 views

Converting map to use space oblique mercator projection using ArcGIS for Desktop?

I have a map document in ArcMap which I want to convert to using Space oblique mercator projection, but I am not sure if ArcMap supports it. Any hints on how to achieve this?
2
votes
1answer
2k views

Why is my .prj file not being read by QGIS?

First off, I am new to GIS. I am using qgis (1.8.0), and have been given a shapefile containing .shp, .prj, .shx, .dbf, however qgis will not load the .prj file stating an invalid data source. ...
2
votes
2answers
5k views

How to create custom coordinate system in ArcGIS Desktop?

I have a series of control points with xy coordinates in both NAD83 UTM and in a local grid. How can I go about creating a new projection file in ArcGIS 10 for the local grid?