Tag Archives: vector layer

Point coordinates to polygon – part II

Posted on January 17, 2013 by

In my previous article, I showed how you can convert point coordinates into a polygon vector layer in QGIS. So how about GRASS GIS? Like in my previous post, let’s assume you have a text file with two columns with … Continue reading →

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Exporting vector layer as kml in QGIS

Posted on July 31, 2012 by

In my previous post I described how to export a vector layer from GRASS GIS as kml file. The key was to use the dsco parameter to define the columns that should be used for the Name and Description fields … Continue reading →

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Exporting point file as kml in GRASS GIS

Posted on July 31, 2012 by

The v.out.ogr function in GRASS GIS let you export your vector layer to any format supported by OGR (it is basically an interface to the GDAL/OGR function ogr2ogr). This includes kml files. E.g., v.out.ogr input=labels layer=1 dsn=/home/paulo/test.kml format=KML will export … Continue reading →

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Reprojecting your layer in Spatialite

Posted on July 4, 2012 by

I have a vector layer ‘nursery data’ in a Spatialite database. The coordinate reference system of the layer is WGS84 geodetic (EPSG 4326). What if I need to reproject the layer in WGS84/UTM37N (EPSG 32637)?

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From attribute table to QGIS style file – step 2

Posted on July 2, 2012 by

This post is a follow up on an earlier post where I described how to use a column with RGB values in an (attribute) table to create mapping symbols for QGIS. The next step is to create the qml legend … Continue reading →

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From attribute table to QGIS style file – step 1

Posted on June 15, 2012 by

I have a large number of GRASS vector layers with in the attribute table a RGB column defining the colours of the corresponding mapping units. Unfortunately, unlike GRASS, QGIS does not offer the option to to set colours from an … Continue reading →

Posted in Data handling, GIS, GRASS GIS, QGIS | Tagged , , , , , | 5 Comments

Find and select duplicate values in your vector attribute table

Posted on May 4, 2012 by

Suppose you have a vector layer in your GRASS GIS database and you want to find all duplicate values in one of the columns of the attribute table of that layer? If you are using SQLite or PostgreSQL as the … Continue reading →

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Extract X and Y coordinates from a spatial table in Spatialite

Posted on February 21, 2012 by

A quick note on adding two columns with X and Y values in a vector layer in spatialite. Spatialite stores the information about the geometry in binary format in the ‘Geometry’ field. You can use the Spatialite function AsText() to … Continue reading →

Posted in Data handling, Spatialite, SQLite | Tagged , , , , , | 1 Comment