2
votes
1answer
61 views

Georeferencing a raster using GDAL and Python

I want to georeference a raster using python and GDAL. My current approach is to call gdal_translate and gdalwarp using os.system and an ugly list of ground control points. I'd really like a way to do ...
7
votes
0answers
149 views

Geotransformation for polar stereographic?

I'm currently working to import CANGRID climate data (provided as Surfer Grid ascii, ".grd" files) into ArcGIS. The grid is 95 rows by 125 columns in size.Metadata provides lat/lon of origin (lower ...
0
votes
0answers
81 views

Transforming between epsg:3857 and Google Maps Tile coordinates

Hio, I used to use a simple python project (https://github.com/hrldcpr/mercator.py) to convert between wgs84 and google maps tile coordinates. This project doesn't have a license, and looks like it ...
0
votes
2answers
69 views

GDAL for Python: extracting subdomains from NetCDF file?

I need to make a script that processes a NetCDF file that contains 3 days of hourly forecast data from the norwegian meteorological office. The NetCDF file contains various data I need ...
1
vote
1answer
101 views

Pyproj: converting WGS84 to Robinson

I have a WGS84 coordinate pair (37.7749295, -122.4194155). I have an image that is a Robinson Map Projection of the world. I'm trying to write a python script to locate my WGS84 coordinate on my ...
2
votes
1answer
38 views

Error reading large virtual raster with rasterio: “Cannot invert degenerate transform”

I've created a virtual raster using gdalbuildvrt, which covers a large extent (England) at a high resolution. The data is fairly sparse, focused around the coastlines with no files covering inland ...
0
votes
0answers
46 views

Is it possible to rotate the geographic projection in QGIS?

I'm trying to create a Qgis plugin that can rotate a raster layer in the canvas so that the north is pointing at another direction. Unlike the thread below, I'm open to defining a custom projection. ...
0
votes
0answers
77 views

leaflet.js ImageOverlay projection bug

We are trying to display a image over the leaflet map using "ImageOverlay" layer, but it does not work according to expected. In Google Maps works perfectly. Apparently Leaflet just stretches the ...
1
vote
1answer
89 views

My class using ogr to calculate distance is returning incorrect results away from the equator

In an answer to this question ustroetz kindly provided some sample code for use of ogr to do lat/lon distance and point in polygon calculations. I've created a Python class based on his example to do ...
0
votes
0answers
93 views

TileStache : Unknown geometry type in geoJSON file

I'm currently trying to set up a TilSstache server on Ubuntu 12.04 to serve some GeoJSON tiles from a shapefile/JSON file (administratives boundaries) for a web mapping project using the Leaflet ...
0
votes
0answers
26 views

Add a raster specifying the projection in pyqgis

I would like add an raster but I want to specify the projection. If I do : qgis.utils.iface.addRasterLayer(url,layerName) QGIS ask me to specify the projection. I want to this with python. How I ...
0
votes
0answers
98 views

Kartograph - “projection not named”

The Kartograph package looks very promising, so I have been trying play around with it. As it turns out, I have been able to get the most basic map to work (the "world.json" example), but I could not ...
5
votes
2answers
188 views

How do I get the projection of an LAS file using liblas?

I am using the python api of liblas to read/write las files. I would like to get the spatial reference information of the las file using liblas, but have been unable to figure it out. Can anyone ...
3
votes
2answers
131 views

in python, srs.ExportToProj4() returns an empty string, why?

I have a shapefile with the following .prj file: ...
2
votes
3answers
315 views

How to find and apply reprojection parameters?

I have a data set in one projection, and a shapefile in another, and I am trying to combine the two. I am using Python. I apologize for posting a "help me transform coordinates" question on this site ...
5
votes
2answers
698 views

Stereographic projection of WGS84 ellipsoid on a plane[python]

I would like to ask you for help in following task. What I need to do is to derive local x,y coordinates from latitude, longitude, applying stereographic projection of WGS84 ellipsoid on a plane, ...
0
votes
1answer
112 views

Different output from running algorithm in toolbox and from script

I am unable to get the same results when running the qgis:reproject tool from QGIS processing toolbox (QGIS version 2.0.1) as when running it from a Python script (console). In this example I am ...
1
vote
2answers
173 views

No prj file output from qgis:reproject

I'm trying to reproject a vector layer using the 'qgis:reproject' algorithm in the processing/sextante module of QGIS, from Python. This kind of works, but the .prj and .qpj files created after ...
1
vote
2answers
187 views

Using a different projection to calculate areas using the Field Calculator

I have a dataset that is in a WGS84_UTM projected coordinate system, can I force the Field Calculator to use another coordinate system when I use it to calculate areas using pythons ...
3
votes
1answer
337 views

How to render area that crosses 180°?

The problem is that the Chukotka Peninsula is located in the Western Hemisphere. So it is on the left side of Natural Earth Datasets. It needs to be moved to the right. I tried to use following ...
3
votes
1answer
259 views

How to get spatial reference of a shapefile using python?

I always use arcpy.GetParameterAsText to get the spatial reference from the user. There should be a way to decide what is the spatial reference of a shapefile but I can't find it. Something like ...
0
votes
1answer
487 views

Geographic Transformations using ArcPy vs. Coordinate Systems used by ArcGis online basemaps

I have 3 shape files with undefined projection, but I know which one it was used (Lisboa_Hayford_Gauss_IPCC). I need to 1st Define Projection. It works. I need to transform it from WGS_1984, so I've ...
2
votes
1answer
147 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
259 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
1answer
361 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], ...
2
votes
2answers
98 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 ...
1
vote
1answer
694 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 ...
0
votes
2answers
627 views

Tile script (Mapnik) with OpenLayers - Problem with projection (900913)

I use Mapnik python bindings in a geodjango application to render tiles in openlayers with datasource stored in postGIS in 900913 projection. The feature seems to be rendered correctly in the ...
2
votes
1answer
369 views

How to re-project the EASE (Equal Area Scalable Earth) grid with a ~25 km cylindrical projection to WGS84 0.25 degree?

I have nc files ,here is one file https://echange-fichiers.inra.fr/get?k=LUfqiyO1Dl7az5bihnS. from the metadata ,the projection is cylindrical and the resolution is 25 km: ...
2
votes
0answers
173 views

projection discrepancy with gdal (1.9) and proj4

I boiled the problem down to that python example: import sys try: from osgeo import gdal from osgeo import osr except: import gdal import osr if __name__ == '__main__': version_num = ...
2
votes
1answer
1k views

Mapping x, y pixel coordinates to latitude and longitudes on the WGS84 datum

Apologies in advance for the long question, I am fairly confused at this point and I figure if I show my thought process any flaws early on in the piece can be more easily pointed out. I have a grid ...
6
votes
1answer
1k views

Python script to convert Lat Long to ITM (Irish Transverse Mercator)

I am currently working on a python script that converts Lat Long (WGS84) to ITM. The formulas used are based on a paper published by OSGB (Appendix B): ...
3
votes
1answer
569 views

Calculate bounding box + buffer for rendering a map tile with mapnik library

Mapnik library has a Projection object (I'm using Python bindings): spherical_mercator = '+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null ...
5
votes
3answers
1k views

Using arcpy what is the most efficient way of projecting a selection from a large data set?

I have a large data set X(x1-xn) from which I must select consecutively the attributes A(a1-an) from X.fieldsSRC or X.fieldDST and project the selections. I have a functioning arcpy script that does ...
1
vote
0answers
173 views

I am getting a blank layer preview from geoserver after Quick Exporting my shapefile to postgis and then getting postgis to point to geoserver [closed]

What could be the potential problems? Looking at the layer's data fields/form the one thing that isn't filled is the Native SRS and its source, but I have already passed in the projection info as it ...
1
vote
1answer
421 views

Defining multiple projections inside a file gdb [error 000289 failed to alter spatial reference]

I am importing multiple shapefiles into a filegdb in ArcGIS 10, and using the following code to define the projection of the feature once imported, to the .prj of the original .shp file. Here is my ...
5
votes
4answers
2k views

Automate Projection of multiple shp files using ArcPy

I have been trying to create a Python script that will convert all shape files within a folder from GCS WGS 84 to Web Mercator. Below is the code I have so far but what I'm struggling with is how to ...
2
votes
1answer
464 views

How to determine area of pixel in meters with GDAL and Python?

I have a raster loaded in Python using GDAL bindings. I'd like to be able to determine the area of a pixel in meters although I'm not confident that the projection is in meters. On this page I see a ...
9
votes
2answers
2k views

Measuring distance in spherical Mercator vs zoned UTM

I've got points in WGS84 lat/long and I'd like to measure "small" (less than say 5km) distances between them. I can use the haversine formula from http://www.movable-type.co.uk/scripts/latlong.html ...
20
votes
6answers
14k views

Defining projections for multiple shapefiles in ArcMap?

I have over 100 shape files that don't have .prj file and thus when I bring them into ArcMap 10 they show the coordinate system as unknown. I know all of the shape files coordinate system is GCS WGS ...