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

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471 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 ...
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1answer
74 views

When is a projected length calculated via a pythagorean distance more accurate than an ellipsoidal length?

I'm using spatialite 3.0.1 with the following test data (in EPSG: 4326): Name astext(geometry) ---------- -------------------- Belitsa POINT(23.563 41.947) Malko Tarn POINT(27.533 ...
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81 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 ...
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1answer
117 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 ...
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58 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 ...
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183 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 ...
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1answer
368 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 ...
2
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1answer
153 views

Wrong object size after projecting spatial data from one coordinate system to another

I am having problems reprojecting items in ArcMap 10.1 from British National Grid To WGS84. (WKID: 27700 Authority: EPSG to WKID: 102100 Authority: ESRI) All Polygon Layers I project [I use Project ...
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2answers
215 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
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1answer
144 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 ...
3
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1answer
631 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 ...
5
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2answers
3k views

How to display KML image overlays in OpenLayers?

I am working on displaying Ground Overlays on OpenLayers by parsing KML manually. To do so, I was trying to add an image on top of Google Map by looking at GroundOverlay section from ...
3
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2answers
225 views

Converting lat lon into co-ordinates (in ft of m)

I have a set of latitude and longitude of a series of points which specific the trajectory of a vehicle. If I consider the first point as the origin (0,0), is it possible to convert the trajectory ...
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0answers
106 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') > ...
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3answers
5k 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 ...
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0answers
57 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 ...
0
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1answer
418 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
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1answer
95 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 ...
6
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2answers
2k 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. ...
4
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1answer
529 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 ...
0
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1answer
68 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 ...
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1answer
44 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 ...
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0answers
257 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 ...
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462 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 ...
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1answer
1k 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 ...
2
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1answer
127 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 ...
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2answers
2k views

OGR Projection transformation error

I am trying to convert shapefile that was created by FME in EPSG:900913 to EPSG:3857 (I know its the same definition) with OGR in a script. datasource = ogr.Open(os.path.join(dirname,shapefileName)) ...
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80 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 ...
0
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1answer
272 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?
2
votes
1answer
273 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 ...
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1answer
517 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 ...
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170 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 ...
10
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2answers
626 views

how to produce a Peirce quincuncial map?

As far as I know neither PROJ4 nor ESRI tools can apply the Peirce quincuncial projection. Does anybody know what libraries/softwares can manage it?
1
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1answer
676 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 ...
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1answer
350 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"] ...
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0answers
426 views

Moving GPS Points with a VB script - Bearing works well but distance is wrong

I am using a script I found online created in 2003 by one of the commentators here. It is a great script and exactly what I have been looking for and I'm very glad to have found it. It simply takes ...
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2answers
85 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 ...
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1answer
523 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], ...
10
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10answers
10k views

Batch convert lat longs to UTM?

I've got a .csv file that contains a long list of latitude and longitude points. Is there an efficient way to batch convert the list into a projected UTM coordinate system? Thanks.
2
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2answers
150 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 ...
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0answers
271 views

How to overlay 3 different layers using ArcMap

I have to overlay 3 different layers called "Bacino Isonzo Perimetro", "Bacini Tributari Isonzo", and "Isonzo" in ArcMap. Layers'properties are shown below. BACINO ISONZO PERIMETRO Data Type: File ...
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1answer
1k views

Python GDAL: degrees to meters without reprojecting

I am trying to get senseful results in my Python script. I want to measure distance between features in a shapefile. I'm working with the SRS: GCS_WGS_1984, so my units are in degrees. But for the ...
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0answers
1k views

ArcPy 10.1 PointGeometry.projectAs()

I'm trying to reproject an X,Y passed in from an Add-in. So far this works fine: pointGeometry = arcpy.PointGeometry(arcpy.Point(x,y),srIn,False, False) projectedPoint = ...
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1answer
2k views

How to I create a .prj file with the following projection parameters?

I have received shape files that are missing .prj files. The documentation for the shape files describes the projection system as Lambert Conformal Conic and provides the following "Projection ...
0
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1answer
298 views

How can I clean up this OpenLayers code by correctly doing a transform or projection, for an array of features?

I have some features I've created via some Kml data. Now, to display these features on a Google Map, I need to project them from 'EPSG:4326' to 'EPSG:3857'. This works great. Now, i need to convert ...
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1answer
3k views

How to transform World data from EPSG 4326 to EPSG 3857

I have tryed different opensource tools to transform a world data shapefile from 4326 to 3857 but I always have an error. Im not sure, but is it because of Antartica? I have tryed with GDAL and QGIS ...
0
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2answers
1k views

How to scale/reduce my polygon without changing the central lat & long?

I am writing a VBA code to resize my polygon, I get a input as vector points(Shape file). The code below resizes it as according to my scale factor but my central latitude and longitude are also ...
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1answer
384 views

Pseudo Mercator error?

I'm mapping on QGIS, I have a vector layer and his CRS is on EPSG:4326 - WGS 84, but also I wanted to put a satellite image, so when I do it, the image use WGS 84 / Pseudo Mercator. The problem is, ...
0
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1answer
329 views

Why do ArcGIS Area Calculations not match Official Statistics?

I am trying to calculate area of polygons using a shapefile from the world bank where countries are defined. When however I am trying to calcuate the area, the numbers that emerge are different from ...
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269 views

How to find out what projection my data is using?

I have a set of data that I created from gps locations of images. The locations are in decimal. I don't know what projection was used when the data was captured. I used QGIS to display the data with a ...