A coordinate-based data model that represents geographic features as points, lines, and polygons.

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5
votes
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324 views

QGIS: How to reverse vertex ordering in polygons

I am working with an Oracle spatial connection in QGIS through which I am accessing and editing a vector layer. I find that when I edit a geometry, the vertex ordering is reversed (to clockwise in the ...
4
votes
0answers
82 views

Import Vector data to QGIS from pdf and apply georeference

I am Using QGIS 2.14. I have a pdf created by Mapinfo, it contains multiple layers of vector data that I can open as separate vector layers in qgis. However no map projection data was saved to the ...
4
votes
0answers
65 views

Buffer neighbouring polygons without overlap using QGIS

Is it possible to create a buffer around neighbouring polygons, so that the new polygons do not overlap? Preferably in QGIS but any other tool will do. So instead of the first result I would like ...
4
votes
0answers
2k views

problem with saving to esri file

I was using Wroclaw 1.7/GDAL 1.9(earlier release)/Grass 6.4/GSL 1.15-2 and started getting the following message when saving any item to esri format. "Export to vector file failed. Error: creation of ...
3
votes
0answers
13 views

How to snap vectors to vertices for ROI delineation

I am trying to manually extract a set of ROIs in ENVI 5.0. However, I can't seem to successfully line up the vector to be flush with the boundary of the pixels, which means I don't have fine-tune ...
3
votes
0answers
137 views

Joining csv file to vector layer in Processing modeler?

I am trying to join a simple csv file of values to a vector layer within Processing modeler. The match would be on an id held by both files. The csv file has no geometry. I can do this easily in ...
3
votes
0answers
282 views

Cross-browser marker animation in OpenLayers

Currently I'm trying to implement animated markers in OpenLayers. I'm using PNGs for the markers, set by the externalGraphic style property on an OpenLayers.Layer.Vector. I need to be able to make ...
3
votes
0answers
453 views

How to Create a Vector Field from Separate u and v Data Files?

I am using Quantum GIS and trying to create a vector field using data from two separate netcdfs. One contains the u data, one contains the v data. Can this be done, and if so, how? Thanks. Jason
3
votes
0answers
274 views

Is there a way to create raster by interpolating point values using GeoTools 8.2?

im new in using GeoTools (8.2). I was able to create shp from asc file which contains my data. Now my question is is there a simple way to create (interpolate) a simple shapefile (only points) to ...
3
votes
0answers
1k views

How to get turn angle, line orientation and line length in ArcMap 9.3.1?

I am mapping and analysing animal movements using arcgis 9.3.1 along with Hawthorne Beyer's GME, and am trying to utilise the correlated random walk commands, but in order to do this I need to find ...
2
votes
0answers
17 views

Trigger event after KML Layer completely loaded

I want to set the bounds of my map after a Vector (KML) Layer is loaded. kmllayer.events.register('refresh', kmllayer, function(evt) { map.zoomToExtent(kmllayer.getDataExtent()); }); In the ...
2
votes
0answers
31 views

Converting u and v from WGS84 to NZTM2000 - Do I need to do vector conversion?

I have u and v wind component values in latitude and longitude in WGS84. I want to convert this to NZTM2000. I've converted the lat/lon in ArcView - (and will try in R) - but do I need to also do some ...
2
votes
0answers
22 views

QGIS upgrade from 1.8 to 2.12: Vector layers are not displayed

I just updated my very outdated version of QGIS. I was running 1.8 and thought the new version would work out a couple kinks that had developed. Well, now I can't even figure out how to make my vector ...
2
votes
0answers
56 views

QGIS becomes unresponsive when adding new vector layers?

QGIS suddenly won't allow addition of new vector layers when running on PC (Lyon 2.12.1). I've reinstalled it, no help. I've recently changed to Windows 10 from 7, otherwise nothing much has changed ...
2
votes
0answers
70 views

QGIS 2.12.3 Crashes on buffering line vectors

I'm using QGIS 2.12.3 and I'm trying to create a buffer of 100 mt around a line vector using the Vector - Geoprocessing Buffer tool, but qgis crashes at every try. I've already checked that the RS of ...
2
votes
0answers
43 views

Combining adjacent shapefiles and merging neighbor polygons currently divided by quad boundaries

The project I'm working on has been mapping ecological sites in ArcGIS on a quad-by-quad basis for the past 10 years. When entered into GIS, each quad has its own shapefile and the sites are cut off ...
2
votes
0answers
63 views

Regridding vector values

I'm trying to regrid and interpolate vector values from WAM model output. I got WAM model netCDF output in rotated grid, I need to interpolate it to another grid which is some variant of LAEA ...
2
votes
0answers
86 views

QGIS 2.12 map composer issue with vectors

i am making a map that includes all kinds of vector layers; the map looks perfect in QGIS 2.12 Lyon as well as in map composer. None of the layers have scale-dipendent visibility; i have the following ...
2
votes
0answers
37 views

How can I measure the distance between many polygon features and either another polygon or a line in QGIS?

I often have to manually measure the distance between a single site and other sites around it, but obviously this can get long-winded and I feel like there must be a much more efficient way of doing ...
2
votes
0answers
68 views

Error trying to save vectorfile in QGIS 2.10?

I'm trying to save some changes I made in a vector file (polygons) in QGIS 2.10. The file contains properties and I want to merge two of them into one. I toggled and selected the two and then pressed ...
2
votes
0answers
103 views

How to tell if map service is fully vector or raster?

sorry if this is a duplicate, but I was wondering how to tell if a map service (in web browser) is vector based or raster based? What I think to understood so far is that Google Maps for example is ...
2
votes
0answers
76 views

Creating a 3D model of airspace that I can interrogate to see if some other feature (like a tree) will intrude into the airspace

The goal is to create a 3D model of imaginary planes in space that I can interrogate to see where other objects in the vicinity of the model cut through any part of that plane. For example, an ...
2
votes
0answers
83 views

PyQgis - Adding attributes to a POSTGIS layer

After reading @underdark's answer to this question on creating a new vector layer and @Matthias Kuhn's to this one on field calculation, I wrote a script that allows me to calcultate the mean ...
2
votes
0answers
110 views

How to make a model with more than 2 input layers for buffering and merging?

Would it be possible to add more inputs to Buffer and Merge? From what I can see there is a limit of two input layers per both. As far as I know this is possible in ArcGIS's Model Builder but from the ...
2
votes
0answers
105 views

QGIS's “Points in Polygon” counts zero in every census tract

I am mapping the location of incidents of asthma using QGIS. I would like to count how many points are in census tracts to better understand the areas where asthma occurs most frequently. My map ...
2
votes
0answers
104 views

Connect two contour lines with calculated line length

Is it possible to make a plugin for QGIS like PEGGER for arcview 3.2? Problem is, how to make path over contour lines with a gradient in percent? Formula is: K= e*100/G*M ; K=10*100/0.08*10000=1.25m ...
2
votes
0answers
24 views

Help getting a Mathematical Representation within a Layer's Attribute Table

I'v been playing around with Vector Coding and was wondering if there was any Plugins out there that might let me represent Vectors within a layer as it's Mathematic attributes in the Layer's ...
2
votes
0answers
36 views

Aggregate nearby points to develop equally sized regions in QGIS

I have a list of 4,500 points (lat, long, unique id, attribute). I also have a service territory which all of the points fall into. I would like to break the service territory (polygon) into 6 ...
2
votes
0answers
251 views

Free implementation of Polynomial Approximation with Exponential Kernel (PAEK) algorithm

I need a Free (i.e. Open Source) implementation of the Polynomial Approximation with Exponential Kernel (PAEK) algorithm, preferably in C, C++, Python, Julia or R. The algorithm is one of the methods ...
2
votes
0answers
50 views

how to display 2 wfs layer at the same time from mapserver?

I have two wfs vector layers. When i show only one layer, it works. But doesn't work when i'm trying to show 2 wfs layers at the same time. How to show 2 wfs layers together? I'm using OpenLayers. ...
2
votes
0answers
686 views

How to merge overlapping and duplicate lines from vector layer to one single line?

I used the "polygone to line" tool from QGis, to get a line-layer from this polygon-layer: unfortunatly this causes overlapping and duplicate lines, after I broke the qgis-export via GRASS into ...
2
votes
0answers
48 views

QGIS polygon areas inside a polygon

I'm having hard time doing the following analysis in QGIS: I have watershed polygons with individual IDs. Then I have four different shape files, each having different land use polygons. I would ...
2
votes
0answers
101 views

Adding feature to GeoServer vector layer using WFS-T in absence of fid index?

I want to add a feature to GeoServer vector layer with WFS-T. When I use saveStrategy.save(), an error returned that said: java.io.IOException: current fid index is null, next must be called ...
2
votes
0answers
187 views

What C/C++ libraries exist to transform vectors between map projections

Has anybody written a C/C++ library (preferably one that is aware of Proj.4 definition strings) that has a set of routines to convert vector quantities (e.g., wind speed and direction) between map ...
2
votes
0answers
468 views

Editing QGIS point layer: retrieve attributes of intersecting line layer

I'm creating a custom editing form using QGIS 2.0 and would like to modify the mouse event when creating a point. I've gotten a start by reading this thread: How to programatically check for a mouse ...
2
votes
0answers
361 views

How to best intersect vector data with raster data?

I have Open Street Map [OSM] data imported so that I can access the geometry of buildings. I have also loaded SRTM digital height data from NASA from a GeoTIFF raster. I have projected the raster into ...
2
votes
0answers
528 views

How Can i create a Vector layer from selected features qgis

In my qgis plugin i select dynamically features from a Vector layer. and currently i create a new layer from selection on combining all feature into a new feature: theField = QgsField self.theString ...
2
votes
0answers
331 views

How to render a transparent raster layer on top of one or more vector layers with PyQgis?

I been trying to render a map with a 3 vector layers and one raster layer. The idea is that the raster layer should be on top of the other 3 vector layers. The problem is that even when I add the ...
2
votes
0answers
82 views

Can I edit WMS layer or KML layer?

I am using Openlayers and until now i have been using OSM as background and i got points from my db (mySQL) and add them to vector layer, then i could modify them and save it back to the server. now i ...
2
votes
0answers
79 views

Moving legend items up and down in QGIS

How can I change sort order in layer properties styles tab? The only way I've found is to change their labels and order by it.
2
votes
0answers
118 views

Base station coverage analysis in QGIS

I want to find base station coverage for a instant location. I have building data. And i determine optimum coverage as 500m far away from a base station (buffer). So how can i find optimum base ...
2
votes
0answers
574 views

popular solution for display both tiles and vector data in android map app

We are planning to build a location based app like google map in android. We have some experiences in the PC development,that's to say we have a similar javascript api like google map javascript api, ...
2
votes
0answers
653 views

how to search a vector/wfs layer

I'm using Geoserver/PostGIS/openLayers I've succesfully set a vector layer. And now I'm trying to create a search functionality. But something goes wrong. First I set up the layer and add some basic ...
2
votes
0answers
216 views

Overlay Shapefile onto Geotiff

I have a Geotiff map and I want to overlay a Shapefile onto it. Ideally I want to specify a 'nice' style for the polygons e.g. have them opaque (for now all polygons should be the same). I want to ...
2
votes
0answers
542 views

Creating a sidewalk map for a walkability survey

If I wanted to do my own walkability survey of my city, what tools could I use? I have map data from OpenStreetMap, but I have to consider that streets have two sides (which aren't always accessible ...
1
vote
0answers
23 views

Missing vector features when import from .sqlite to postgis?

I imported vector data from a .sqlite file to PostGIS but not all of my vector features imported. I haven't been able to determine a reason for most of the loss of features between the databases ...
1
vote
0answers
24 views

Clipping vector polygons by previous vector polygons in same layer in QGIS

I have extremely large datasets as vector polygons in single layers. The polygons are in an order. I want the previous ordered polygons to clip the later polygons. Therefore, once an area has been ...
1
vote
0answers
30 views

Importing geospatial PDFs with QGIS

I've been using GDAL to work with geospatial PDFs to make geotifs and have been running into some issues, so I started working with QGIS. A fine product I might add. When I select a directory ...
1
vote
0answers
26 views

Command line join attributes by location using OGR

I have two overlapping vector files (polygons and sample) and want to do a spatial join from the command line to extract all features in polygons that intersect with sample. Essentially I want to have ...
1
vote
0answers
31 views

How to get a multi-attributes vector from an SRTM raster in QGIS?

I split an SRTM raster into 3 different raster files representing the altitude, the slope and the exposure, using QGIS DEM analysis tools. How can I output a single vector file with the 3 attributes ...