The OGR Simple Features Library is a C++ open source library (and command line tools) providing access to vector file formats.
1
vote
1answer
24 views
R : convert a spatial polygon objet to spatial polygon data frame
My goal is to modify an existing shapefile by merging certain polygons.
After importing the shapefile and using the UnionSpatialPolygons command, I get the polygon outline that I want.
However, this ...
5
votes
1answer
64 views
Python - OGR: Transform coordinates from meter to decimal degrees
I have a point in a shapefile. The shapefile is in a WGS_1984_Web_Mercator Projected Coordinate System. I want to get the coordinates of that point in decimal degrees with GDAL/OGR in Python.
I am ...
0
votes
0answers
29 views
Python GDAL/OGR: check lines geometries connectivity
I'm working with shapefiles representing roads, so basically it's stored as (poly)lines.
I need to perform a road connectivity checking. In other words, I want to ensure that roads meant to ...
1
vote
1answer
29 views
Batch convert OSM/PBF data
I need to import some OSM data about a region of Italy into a SHP file or Postgres DB, possibly with batch process.
I already use OGR2OGR to batch import data from SHP to Oracle and Postgres and I ...
1
vote
1answer
18 views
OGR UnionCascaded gives strange lines (flat polygons)
I'm using OGR to perform a union using UnionCascaded. All my polygons have been created by GDAL polygonize which ensures that all polygons follow pixel edges and should therefore align nicely. But I ...
3
votes
2answers
67 views
How to computational efficiently check if there are any overlapping polygons in a group of polygons?
I need to do some processing with groups of polygons. If any of the polygons in the group overlaps other polygon the result is unpredictable and don't throw any error. So, I need to detect if there is ...
0
votes
0answers
20 views
NYC Building Perimeter Shapefile after 2011
I've been using the following NYC building perimeter shapefile from the DOTT for some work. This file however dates back to 2010. Is there a newer one available, and if so where?
I have found this ...
1
vote
1answer
39 views
GDAL SQL syntax to add field an put values
I try to make a new field in my attribute table and put in values from another field after converting from character to integer but can't get the right syntax. I run this as shell-script in MSYS.
cd ...
0
votes
0answers
30 views
Is QGIS OGR plug-in data provider (based on Postgres) limited to 500 features in layer?
I developed a plug-in based on OGR. It works fine but when I want to add a vector data (using my plug-in) I get 1449 features (with 76 columns) in my layer. Then I select this layer and load it.
...
1
vote
1answer
92 views
Creating prepared geometries with OGR from Python
Is it possible to create a prepared geometry object using the Python SWIG geos.ogr module? It seems that Shapely and GeoDjango both have this functionality, but I can't see any mention of it in the ...
2
votes
3answers
99 views
How to test if geometry is inside another?
I need to tell whether geometries from a shapefile are inside other geometries or not.
For example, I want to test if there are trees (represented as points in trees.shp) inside the urban areas ...
1
vote
0answers
28 views
how to get correct geo reference system for a VMap
I am new to GIS, trying to read the GeoRef System for VMap by using the following code:
OGRSpatialReference *ref = layer->GetSpatialRef();
if( ref )
{
QString georefSystem = ...
7
votes
1answer
104 views
How to rename field names in a shapefile?
I need to rename the field names (attributes) in a shapefile. Is there an easy way to do this from the command line?
0
votes
4answers
159 views
preferred source format for OGR conversion to GeoJSON
I'm relatively new to OGR and GIS in general. Most of the sources I look at give a choice of ESRI shapefile and MapInfo formats. I'm using ogr2ogr to convert these to GeoJSON for import into ...
2
votes
0answers
46 views
traversing KML files with ogr python
i'm new to OGR processing and KML format so be gentle:
i've got a series of KML files all containing multiple regions partitioning a larger area in each. i also have a series of geocoded points for ...
2
votes
1answer
76 views
OGR - Weird GeomType -2147483645 on polygon shapefile
I am trying to import a shapefile (multipolygon) in an app with ogr but I got an error about invalid geom type. If I inspect the data with ogr like this:
datasource = ogr.Open("c:\\temp\\data.shp")
...
0
votes
1answer
85 views
OGR OSM-driver unable to open datasource
I want to read an OSM file with OGR. I use Version GDAL 1.9.1, released 2012/05/15.
To read a SQLITE file works fine:
$ ogrinfo test.sqlite
INFO: Open of `test.sqlite'
using driver `SQLite' ...
1
vote
4answers
98 views
Get vector features inside a specific extent
The problem:
I have a very large vector layer with many features and a much smaller raster layer in a defined region. I want to get only those vector features which are within the raster layers ...
0
votes
1answer
38 views
OGR shows no layers
I have an ESRI File Geodatabase (FileGDB) (size is 15+GB), which has over 10 layers, when I open it up in ArcGIS, everything seems to be working.
I want to move this database to postgreSQL with OGR ...
0
votes
0answers
35 views
QgsVectorLayer: How to load files containing multiple layers
I’m trying to load all layers from a ZIP-file using the OGR-Dataprovider.
vlayer = QgsVectorLayer("/path/file.zip", "ZIP-Layer", "ogr")
will load only the first layer.
Any idea how to load all ...
2
votes
1answer
112 views
better way to duplicate a layer using ogr in python?
I'm splitting a large shapefile into many smaller ones using ogr. I'd like to just copy all of the field and layer config information from the original. Here's how I'm doing it now:
src = ...
2
votes
1answer
88 views
Need help assigning values to field using OGR in python
I've got a similar question to this one How to programatically populate a shapefile field with polygon areas in OGR?, but the solution doesn't seem to be working for me. I am trying to import a ...
0
votes
0answers
41 views
How to expand Ogr Sql Functionality
I'm using Ogr2Ogr for some geometric & querying operations by storing the results in SQLite files.In SQLite there are some functions I use.For that,I need to extent sql functionality.For that I'm ...
0
votes
0answers
38 views
Using GDAL/OGR exes in php
could you point me in the next logical direction? I wanted to use the gdal and run the exe commands through my web application, but have no clue what the next step should be after running the ...
2
votes
1answer
76 views
need help for script checking topology using ogr in python
My main goal is to create a new feature indicating if the line features intersect each other as well as if they are not connected to a feature.
My problem is how to identify the intersecting and not ...
0
votes
2answers
36 views
OGR GetX() returns always zero
I am trying to get the first x-coordinates of a polygon. However I only get zero in return. What could cause that?
import os, sys, gdal, ogr
from gdalconst import *
driver = ...
2
votes
1answer
137 views
Convex Quadrilateral Polygons subdivision in equal parts using Python / OGR
Consider an irregular polygon (P) which has four vertices.
I would like to subdivide P into smaller polygons as shown here http://i.stack.imgur.com/4SKhB.jpg
In the old days I was using ArcGIS 9.3 ...
2
votes
1answer
44 views
OGR CreateLayer returns TypeError
I'm trying to create a shapefile layer based on the spatial projection of an already existing raster. (Ultimately, this will be used in gdal.Polygonize to get a shape from my raster data.) However, I ...
3
votes
1answer
76 views
GDAL OGR distance different than in ArcGIS
I want to determine the shortest distance between a point and a line. I use the following Python script to do so. If I compare the result of the script with the result of ArcMap's Near Analysis, I get ...
3
votes
1answer
73 views
OGR Info - Check for spatial index?
If we want to get information about a vector layer (shapefile for example) we could use ogrinfo:
ogrinfo -so myshapefile.shp mylayer
This returns a lot of pertinent information about the shapefile. ...
2
votes
0answers
61 views
Custom python datasource to QGIS
I'm working on a homebrew spatial feature data format, and using Python to write it's API.
It occoured to me that use some tool like QGIS to display my data would be very nice to have, for debug/test ...
0
votes
1answer
192 views
Installing GDAL with Java Bindings (gdal.jar) on Ubuntu 12.10
I am trying to build a postgis importer for mutliple shapefiles. After geotools took orders of magnitude longer than shp2pgsql to import my data, I decided to attempt to use the java bindings to GDAL ...
2
votes
1answer
49 views
QGIS QgsOgrProvider library
I asked a question here:
http://stackoverflow.com/questions/14790463/qgis-copy-layer-in-c-plugin
and I was suggested to find the library which provides QgsOgrProvider::createEmptyLayer() function. Can ...
2
votes
1answer
103 views
How to debug ogr2ogr ERROR 1: Did not get at least 2 values or invalid number of set of coordinates?
I'm trying to convert a government data contour GML (http://geo.data.linz.gv.at/katalog/geodata/hoehenschichten/2011/1m-Hoehenschichten.gml) to Shapefile.
It seems like it was created by FME:
...
4
votes
1answer
71 views
How to use -lco options in gdal_contour?
I'm trying to create contours from geotiff raster with gdal_contour. My output format is Postgresql and I would like to ovewrite the existing table.
When I do:
gdal_contour -a 1 -f PostgreSQL -i 50 ...
3
votes
3answers
289 views
Python OGR: convert a point geometry into polygon
I'm writing a routine for creating the convex hull envelop around shapefiles of islands.
I could read the data, extract polygons vertices into a geometry and then compute the convex hull.
Now I need ...
3
votes
1answer
76 views
shapefile batch clip and merge combined
I have two shapefiles, one is polyline, the other polygon. For each polygon I would like to clip the polyline vectors inside. Using arcpy I already found part of a possible solution: ...
2
votes
1answer
57 views
How to interpret the OSGeo4w software version under Advanced Install option?
When choosing to install QGIS Desktop using the OSGeo4w advanced install option, I noticed that there are what looks like ambiguous software versions to choose.
For example, currently QGIS Desktop ...
1
vote
1answer
57 views
SHAPE FILE to TIGER with OGR
How do I convert SHAPE FILE to TIGER using GDAL (OGR). I try but throw following error:(layer number)is not a known TIGER/Line layer.
0
votes
2answers
62 views
OGR: Meaning of “2.5D extension as per 99-402”
I'm looking at the enum defs in ogr_core.h. I see a bunch with comments that read:
2.5D extension as per 99-402.
What in the world does that mean? Presumably it's referencing a spec or RFC?
...
3
votes
1answer
135 views
Simplify polygon in OGR
We use ArcObjects pretty heavily and simplify polygons using something similar to the ITopologicalOperation::Simplify(void). No tolerance is passed in as the parameter (it uses the XY tolerance of ...
10
votes
1answer
553 views
How do I get the pixel value of a GDAL raster under an OGR point without NumPy?
I am working on a computational model of the abundance of wild pollinators across a landscape. The model itself is complete, and I am now struggling with a post-processing step.
I have my GDAL ...
5
votes
1answer
91 views
GDAL/OGR Determine if dataset is raster or vector
I am writing a script using the GDAL/OGR Python bindings and it is possible that the user may provide a raster dataset or a vector dataset as input. If the user provides a vector dataset, the script ...
3
votes
1answer
484 views
How do you open shapefiles with ogr2ogr
I'm following along the D3 tutorial, and on this line:
ogr2ogr \
-f GeoJSON \
-where "adm0_a3 IN ('GBR', 'IRL')" \
subunits.json \
ne_10m_admin_0_map_subunits.shp
run into the following ...
4
votes
1answer
192 views
Efficient computation of nearest distance for each point to closest polygon
I'm looking for a more efficient way to compute the nearest distance between features from 2 layers, in this example for each point the nearest distance to the closest polygon. Is there a more ...
4
votes
2answers
190 views
How do I Capture GDAL projection and create matching output (OGR or GDAL) shape files?
Working in C++, using GDAL and OGR: Depending on what the user has supplied for image input, I need to output point (or other) shape files in the same projection as the input raster images. The ...
4
votes
2answers
120 views
how to cast integer to float in an ogrinfo sql statement?
I have a shapefile for which I would like to add the values in a column.
As the sum exceed the capacity of an integer, I need to cast values to a float.
I tried the following:
ogrinfo -sql "SELECT ...
2
votes
2answers
166 views
OSR Python testSR.ImportFromEPSG(4326) returns empty spatial reference
This is empty using Python .ImportFromEPSG(4326):
import osr
#this fails:
testSR = osr.SpatialReference()
testSR.ImportFromEPSG(4326)
print testSR.ExportToPrettyWkt()
#why did the import from EPSG ...
2
votes
1answer
171 views
How to bulk delete shapefile columns?
I have shape-file with next attribute table:
- name of features, unique number for each feature of layer
I must split shape-file by NAME field, but in result in attribute tables of layers should be ...
0
votes
1answer
114 views
Why do I get an OGR error when attempting to save an edited Shapefile?
I often get an ogr error when I try to save a shapefile after working on it in Qgis ( adding features, removing, modifying attributes.. )
The error says :
"OGR ERROR : Attempt to delete shape with ...
