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

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5
votes
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279 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
40 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
129 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
257 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
154 views

Is there a tool for automated quality assurance for vector data captured on raster data?

I wonder whether is any tool(or script) in ArcGIS or QGIS which allows to make an automated quality assurance for vector data captured on raster data? vector data on binary raster:
3
votes
0answers
414 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
246 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
24 views

save shape file as grouped/layered vector file

I want to get the 10m natural earth countries file into a mercator projection and then into a vector file (svg, ai, etc) where for each country, its main land and any of its islands are in a single ...
2
votes
0answers
33 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
25 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
47 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
64 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
26 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
59 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
86 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
55 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
68 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
79 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
81 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
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
30 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
48 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
561 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
100 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
149 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
322 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
470 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
309 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
80 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
75 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
111 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
546 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
627 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
206 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
512 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
11 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 ...
1
vote
0answers
19 views

How to combine population density data to land use data?

i have census data and land use data in vector format. I tried to combine the population density vector data with land use data set, but every-time it gives me wrong output. Moreover, my land use ...
1
vote
0answers
13 views

How do I generate a sampling path by numbering points?

I need to number points from left to right and then the next row of points the numbering must continue from right to left, then again from left to right the row thereafter - and so on, and so on. ...
1
vote
0answers
28 views

Using arcpy to add several rasters

I need to do some raster/vector processing on some non-overlapping tiles. My python script needs to find the correct tiles and then extract the raster values and count them up. My script needs to be ...
1
vote
0answers
29 views

I clip a raster with a vector mask in qgis, the result is correct but its a little bit of, why is this?

On one side the result is "bleeding" over the vector on the other side its more than one raster pixel from the vector on the inside. How to correct this? http://i.imgur.com/d0v6mqt.png ...
1
vote
0answers
48 views

Using MySQL vector with QGIS?

I have a problem with mysql vector; when I connect to the MySQL table (containing a geometry column), the attribute table is loaded correctly, the map is centered properly but the geometries are not ...
1
vote
0answers
25 views

pgr_nodeNetwork doesn't place new nodes properly

I wanted to use pgr_nodeNetwork tool to split lines where there's no vertex on intersection. The tool doesn't seem to work as expected, though. It doesn't place new nodes right where the two lines ...
1
vote
0answers
42 views

Data dependent override on colour and linewidth of line pattern fill not working after upgrade to QGIS 2.12

I have recently upgraded to QGIS 2.12 which has resulted in a problem with one of my projects, whereby the data dependent override of the line width and colour of a line pattern fill and SVG marker ...
1
vote
0answers
18 views

Accessing feature legend style name using QGIS?

I have a vector layer classified by some combination of field values. I want to add a field for each feature, filled with the legend style name of the element. How can I do this? via Function ...
1
vote
0answers
21 views

How does qgis render vector layer on screen ? How can I do the same in a mobile device

Can you please tell me how does qgis software render the vector layers on the screen. I have a geojson file and I need to map its contents on the screen just like qgis does but without using base map ...
1
vote
0answers
29 views

Distance Analysis from single point to multiple points on vector layers

Is it possible to do the following in QGIS: Create a text file that plots the distance from a single point (stored in one layer) and multiple points (stored in another layer). I have tried to use ...
1
vote
0answers
52 views

Alternatives to QGIS difference tool

I have a very large shapefile of building polygons and a shapefile of the country they reside in (England). The building shapefile was built by merging 94 smaller shapefiles. Both files have the same ...