A map projection is any method of representing the surface of a sphere or other three-dimensional body on a plane

learn more… | top users | synonyms (1)

1
vote
1answer
285 views

EPSG:4326, EPSG:3857, JOSM and unprojections

It is said here that EPSG:4326 is not a projection. In my mind, a projection is a transformation of the surface of the Earth producing a flat image, notably a bitmap. We know that WGS84 (World ...
0
votes
0answers
90 views

Map doesn't show anything in img file (WMS-Mapserver)

Actually in a practical Project we wanted to use OpenLayer and MapServer to display our data using WMS, but We can't find a proper srs or EPSG code. One of the ITC students said, we have to change our ...
2
votes
3answers
378 views

What is the formula for calculating world coordinates for a given LatLng in Google maps?

I want to calculate a given LatLng to the world coordinate . I know I can use the internal projection of Google maps like this: var map=new google.maps.Map(...); ...
0
votes
2answers
204 views

Calculation for conversion of Lat/Lon to World Geographic Reference System (GEOREF)

Does any one have a reference to, or the actual code, to convert Lat / Lons to Georef code (http://en.wikipedia.org/wiki/Georef)? I am also interested in finding a conversion from lat/lon to MGRS. ...
2
votes
1answer
116 views

Stumped on python looping and data dictionaries

I have been stumped getting my python code to work for a while now. I've been using python for the last several years on and off for simple things, but I am far from an expert in python. I am trying ...
6
votes
1answer
204 views

Geometry Projection Speed Test

Lately I've been using the OGR projection classes that come with ogr/gdal, but pyproj was recommended to me, so I thought I'd give it a try. To help me decide if I should make the switch, I did a ...
1
vote
2answers
397 views

How can I use GDAL to batch define a projection?

I have a fodler with 1500 ECW rasters, no spatial reference information defined. Can I use GDAL to batch define a projection for all 1500 in the folder?
0
votes
0answers
54 views

Why does ERDAS not like my GDAL output?

I am creating a raster using GDAL and the IMAGINE file doesn't work in ERDAS because it doesn't recognize the projection. Here is the code to generate a sample: from osgeo import gdal projectionWkt ...
0
votes
0answers
121 views

Why is GDAL changing the projection well known text?

I am having an issue with a GDAL raster process, and I have boiled it down into the fact the GDAL appears to be changing the projection name after GDAL has created the raster. This appears to only be ...
1
vote
0answers
39 views

CRS centered on the 180 meridian?

The problem I'm dealing with is the old 180 meridian problem, except I'm not trying to plot or render shapes that cross it, I need to do intersections of lines that cross it. The only spherical ...
0
votes
0answers
86 views

Changing the projection of the output to my OpenLayers click event handler

I've been playing around with the OpenLayers click event handler example, which you can see here. It tell you the coordinates where you have clicked but I am trying to change this to be in decimal ...
2
votes
2answers
131 views

Older British Geological Survey geology maps of Kenya; need complete projection information

I have several geologic maps of Kenya produced by the BGS circa 1993. Noted on each map is the following: Projection:-Transverse Mercator Spheriod:-Clarke 1880 (modified) That's great, but that ...
0
votes
1answer
164 views

Convert from Mercator to transverse Mercator projection in C++?

I'm writing code to import images from a WMS server into some software. However, the software expects the images to be in transverse Mercator, but the WMS server provides it in Mercator. This ends up ...
1
vote
1answer
86 views

openlayers:transform from ITM to 900913 is not accurate

i did a custom projection ITM (Israel TM) and i then am doing transform to all the feature before im adding them to the map, from ITM to 900913 proj because i want to show the feature on the map. this ...
1
vote
1answer
158 views

How to compute area for polygons in an EPSG:4326 shapefile?

I have a shapefile covering the whole globe, in EPSG:4326 (geodetic WGS84). I would need to compute the polygons areas in a metric such as km2. How can I do that in QGIS or with gdal/ogr and having a ...
0
votes
1answer
95 views

Openlayers: transfer from custom projection to map projection

I am building webApp with openlayers that contain a map that allowed insert edit and remove points, my map is now using “EPSG:4326" projection. I have shp files and xlsx files that contain polygons ...
0
votes
0answers
108 views

Moving from ArcGIS to QGIS - projection trouble

Wondering if anyone can help. I have recently discovered QGIS having previously only worked with ArcGIS. I have a set of data I previously worked with which includes water data downloaded from OS ...
3
votes
1answer
151 views

What's the projection of this albanian military map?

I've received some very useful maps of Albania for my work (scale 1:25000) and I would like to georeference them in order to put them together to one Map for my destined regions. Unfortunately I ...
1
vote
2answers
159 views

Measurements across UTM zones, how to apply spatial parameters to a customize a projection?

I have a survey grid that spans 3 UTM zones. Using http://www.epsg-registry.org/ I can get an indication of what projections are available. Where can I find more info on the patterns of distortion ...
0
votes
0answers
76 views

Why does a shapfile shift after transformation?

I have a shapefile created in the raster package (ER_14.3_2000_poly). > #read in a raster file > ER_14.3_2000<-raster('E:/Ecoregions Models/Outputs/ER_14.3/ER_14.3_ConsensusMap3.asc') > ...
3
votes
1answer
159 views

Projection of Shapefiles for Spain (INE)

I downloaded the official shapefiles for the municipalities of Spain from INE here. It has a lot of shapefiles, but I found out that the right one for what I need is esp_muni_0109.shp. I would like ...
1
vote
1answer
91 views

QGIS Layers Not Lining Up

I am new to QGIS, I have been using ArcGIS for most of my maps. I have two layers that are not overlapping properly. One is a shp file from a GIS clearinghouse and another from a delimited text ...
1
vote
3answers
1k views

How to project Google Earth KML files in ArcGIS so that they display properly?

I am sure my question has been answered in the past but I would really appreciate it if someone could help me with this... I have downloaded a KML point file from Google earth and I imported it into ...
2
votes
2answers
206 views

Is GeoServer getting coordinate output in GeoJSON WFS wrong?

When I do a WFS request to GeoServer and specify the SRS like this: http://myserver.com/geoserver/wfs? service=wfs& version=2.0.0& request=GetFeature& ...
1
vote
0answers
33 views

Create oblique projection?

bit of an odd one which isn't necessarily package-specific. I'm trying to make a tshirt with a map section centred on the plane between San Francisco, USA, to Galway, Ireland. The Great Circle line ...
1
vote
2answers
1k views

Choosing the correct value for proj4string for shape file reading in R “MapTools”

I am having a shape file of polygons and another CSV file which contains a list of points as (Lat, Lng) pairs.. I want to check for each (lat, lng) pair from the CSV file which polygon does it fall ...
3
votes
2answers
338 views

GEOTIFF explanation of .aux xml and tfw world file

I want to know how raster images work, I have a set of geotiffs that has no aux, tfw or xml when I check the spatial information in arccatalog, they do have an projection. and they shows correctly. ...
0
votes
1answer
123 views

What's the best way to add a projection to GDAL?

I have a number of files in Maryland State-Plane (US foot) that have the following wkt: "PROJCS["NAD_1983_StatePlane_Maryland_FIPS_1900_Feet", GEOGCS["NAD83", DATUM["North_American_Datum_1983", ...
3
votes
1answer
78 views

Should states/provinces be stored as geographic or geometric data types?

While reading the GeoDjango documentation, they advise using geometric rather than the geographic data type when storing values that are on a continental scale. The Canadian province of Ontario, for ...
3
votes
1answer
195 views

PostGIS spatial reference ID (SRID) for regular cartesian coordinate system?

I would like to store a polygon as a set of 2D points represented as x, y coordinates of a Cartesian coordinate system. Which spatial reference can I use? Looking at my spatial_ref_sys table, all the ...
1
vote
1answer
377 views

Transform regular lat/lon to rotated lat/lon

I am currently working with climate data projected in a rotated lat/lon grid and came across this excellent 'cookbook' by mkadunc on how to manually transform rotated lat/lon to regular lat/lon: ...
0
votes
1answer
37 views

Projection Issues [duplicate]

I am working with NC shapefiles, I downloaded a national cities shapefile and I can't seem to line them up, actually you can't even see the layers in the same view. I have tried many times to re ...
1
vote
1answer
35 views

Michigan Projection with GDAL or FWTools

Has anyone come across a specific projection for Michigan, specifically: NAD_1983_CORS96_StatePlane_Michigan_South_FIPS_2113_Ft_Intl When I look at spatialreference.org I do not find any instance of ...
0
votes
0answers
100 views

MapServer Mapfile: Scalebar not displaying correct distances?

Scalebar: SCALEBAR LABEL COLOR 0 0 0 SIZE SMALL END STYLE 0 SIZE 180 8 POSITION lc COLOR 0 0 0 UNITS MILES INTERVALS 2 TRANSPARENT TRUE STATUS EMBED END I didn't even ...
1
vote
0answers
166 views

Reprojecting GeoTIFFs to WGS84/UTM

I'm using libgeotiff and proj4 to read and (try to!) process GeoTIFFs. After reading the file, I want to get the corner coordinates in WGS84/UTM - but there are so many functions and parameters to try ...
2
votes
1answer
90 views

Find projection from dataset

I have a dataset that I have pulled from a MaxSea 3d database. I am trying to figure out what projection is used, so I can transform and use the data. I have tried following this guide ...
0
votes
0answers
63 views

Changing projection does not change map extent

I have a shape file with a UTM projection. I want to save the data to a new shape file with a lat/long projection for a mapping system that only can deal with lat/long projections. I open the UTM ...
2
votes
1answer
95 views

Does the Load Data function in ArcCatalog automatically re-project the data?

If I have a feature class within a dataset in one coordinate system and using the Load Data function, load that data into a feature class of a different dataset that's in a different coordinate system ...
0
votes
1answer
93 views

Using the projection of a layer variable to project another in Model Builder in ArcGIS

So in model builder I would like to have one input feature class projected to match the projection of another layer (a raster layer) that is a variable in the model. Can anyone help me achieve this?
1
vote
1answer
197 views

Long range Trilateration from 3 lat, long, range

I've been looking at the following solution to a similar problem Trilateration using 3 latitude and longitude points, and 3 distances However with my problem the 3 points are spread over a large ...
1
vote
1answer
280 views

How to understand GeoTIFF tags?

I'm trying to understand GeoTIFF info, but not getting far. For instance, using listgeo with one file I can get this output: Geotiff_Information: Version: 1 Key_Revision: 1.0 ...
1
vote
0answers
102 views

Trying to convert to EPSG:27700 (Ordnance Survey) projection, unable to do so

I'm trying to code an interface that allows a user to draw a vector shape on openstreetmap, which is then converted to a WKT string, processed by the server and sent of as a WFS query to emapsite ...
1
vote
1answer
504 views

OpenLayers TMS limit zoom and extent

I have a custom map which I get from a mbtiles file with the bounds -13,25,49,60 and zoom from 4 to 10.The display div is dynamic, I mean that it depends on window size and the extent restriction ...
0
votes
0answers
44 views

How to retrieve PROJECTION value for a map?

I am trying to read the Projection from Geotiff/shape file, using gdal 1.9.0 by the following command in the command line... gdalinfo.exe -proj4 map-path but its retuning empty string for ...
0
votes
1answer
232 views

Which CRS fits “Lambert Conformal Conic Projection, Standard Parallels 46.40 and 49.20”?

I am trying to georeference a VFR chart in qgis and I can't figure out which CRS to use. Map projection - Lambert Conformal Conic Projection, Standard Parallels 46.40 and 49.20. Any ideas which ...
1
vote
1answer
139 views

How do you make a function for changing projection with proj4js in Openlayers?

I have included Proj4js in OpenLayers. I would like to create a function (so I can use a make a button). To change the projection of my map. I have included in javascript Proj4js.defs["EPSG:54008"] ...
1
vote
1answer
285 views

Python GDAL/OGR: WGS84 & meters units

I'm dealing with shapefiles projected in: GEOGCS["GCS_WGS_1984", DATUM["WGS_1984", SPHEROID["WGS_84",6378137,298.257223563]], PRIMEM["Greenwich",0], ...
1
vote
2answers
71 views

Error reported when trying to import prj for data points in New Brunswick Canada into QGIS

I have data points recorded with a Trimble GIS. The projection is New Brunswick Sterographic Double Projection, which as near as I can find via a Google search is EPSG:2953. However, when I try to ...
8
votes
3answers
477 views

Distance measurements across UTM zones: use geographic or planar approaches?

I have a survey grid spread across 3 UTM zones (36N, 36S, 37S). I want to find the nearest (or shortest) distances of the centroids of these grids to roads and various points between. It seems like ...
2
votes
2answers
96 views

How to reproject all featureclasses in a database to another database?

I am very new to arcpy and have ArcGIS 10.0 I would like to make a script where I would only have to change two variables in a script (database_input and database_output) so that I can reproject all ...