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

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321 views

Get lat/lon points from image pixels

I need to build an application with the following requirement: shows a map .png picture to user. then, users select several points around the map (I can get the x/y pixels from each point) based on ...
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1answer
187 views

get and change style property openlayers

i need to change the property of some style after its created, and i need to change it with knowing only the string of the property name. i am getting string like "fillColor" and value like "blue", ...
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1answer
89 views

why can't i export geometry data from a shapefile?

I saved the layer using "vector save as" box but even when adding GEOMETRY=AS_XY in the layer box, the csv only showed the id and no gemetry data.
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89 views

How can I add vector tiles to my tileserver?

I created my own tileserver under ubuntu 12.04 as described here: http://switch2osm.org/serving-tiles/building-a-tile-server-from-packages/ now I want to serve the tiles as vectors, I found this: ...
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2answers
2k views

Vector Tile Rendering on iOS

I'm developing an iOS app for displaying my own custom map data (on GeoServer). The SDK I'm using to display my map is route-me (Alpstein fork) as the map viewer for now. route-me supports raster ...
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1answer
31 views

Multiple vertices after editing giving wrong start and end x, y co-ordinates

I have a small problem which I have been fighting to solve but in vain. Initially I generated some polylines across the river at various locations. I found some of them are smaller in size and not ...
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2answers
2k views

How to capture contour lines from OSM cycle map as vector?

In QGIS, there is a plugin to insert a OSM cycle map layer, that brings as an image from http. But I can't convert this OSM Plugin layer to a raster image. I can't even imagine how to get the contour ...
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1answer
19 views

GRASS Add Vector Point

I need to do a viewshed analysis using GRASS. I've got the DEMs loaded; and I simply want to input several (2-4) points (like 41.12345N, 122.34567W from GPS). What is the simplest, most ...
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200 views

How to increase symbol size of polygons when zoomed out?

I have many small polygon scattered. How do I increase size of polygons when zoomed out in qgis? As seen in the image the symbol appears to be lost when I zoom out. Note: I have created a thematic ...
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2answers
101 views

v.what.rast trouble in GRASS GIS 6.4.2

I'm facing a problem using the v.what.rast comand. I'm trying to update the vector "canali" which represents some streams, with the slope value for every single point of the lines. The slope values ...
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1answer
203 views

OpenLayers Strategies

Can we use the strategies OpenLayers.Strategy.Fixed and OpenLayers.Strategy.BBOX simulataneously on same vector layer?
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117 views

How to edit a table in GRASS?

How do I edit a table in GRASS? When importing a vector into GRASS from QGIS, all the attributes are lost and I need these to continue with my analysis.
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159 views

show dwg,as background not as vector

I have some dwg files that i need to show as background on my map, but the DWG is not need to be vector layers, i need only to show them with out the need of using. if i am trying to convert it to ...
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1answer
291 views

Sum of values within a buffer polygon

I need to do the following in QGIS and hope so much anyone could help. I have a vector layer with points. Each point represents a firm with the number of employees in the attribute table. I want to ...
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1answer
218 views

How to draw a custom map on top of base layer

I'm looking for the easiest way to draw a custom layer and export it as a tile cache. Basically what I would like to be able to do is load a base layer, and then draw objects and annotations on top ...
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1answer
621 views

Selection problem in WMS layer using OpenLayers

I added 4 WMS layers (three polygons and one have point geometry) from GeoServer on my webpage My requirement is: I have to select a single polygon of one wms layer using a mouse click. After the ...
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1answer
319 views

Different Styles Within Vector Layer

Is there any way to configure OpenLayers styling method? I have a vector layer and I would like to style the features depending on a value of a flag variables, so I can't use rules. Lets say I have ...
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2answers
787 views

add a vector point on OSM map

I have managed to show Lat and Lon function init() { navigator.geolocation.getCurrentPosition(function(position) { document.getElementById('myloc').innerHTML="Latitude: " + ...
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1answer
185 views

render kml 10mb KML file cordinates data on OSM map throws stop running script error in OpenLayer.js file

I am trying to render the kml file having 18000 line string data on OSM map using openlayer HTTP strategy. To render OSM map i am using GeoExt.MapPanel and ExtJS 3.4 viewport. The problem is I am ...
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1answer
249 views

Openlayers Linestring over edge of map

im trying to create a route displayer for ships. But im struggling with the edges of the map. When going from ie. 179* to 2* it displays a line across the entire map, instead of displaying it on the ...
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1answer
210 views

QGis : superimpose 2 rasters georeferenced (adjustment)

I am pretty new in QGis and I encounter the following problem. I have 2 rasters, let's say, "cadaster" and "tranchot". The raster "tranchot" was georeferenced from the raster "cadaster" with QGis. ...
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1answer
1k views

Add labels above the lines in OpenLayers

How to add labels above the lines? Labels are added as follows: var styleMarkersLabels = new OpenLayers.Style( // стили для надписей узлов { strokeWidth: 2, ...
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1answer
131 views

How to create a new table for a vector file?

I will use v.db.connect but i want to use a new table, and not an existing table to connect it to. What is the GRASS script for it? Thanks!
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7 views

Where can I get vector datasets for Nasarawa state in Nigeria? [migrated]

I would be happy to be pointed to the right direction where I can access vector data for NAsarawa state in Nigeria?
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22 views

Is there a way you can see the spatial query that vector uses?

I am using geoprocessing-tools --> intersections to calculate which points are within my circular buffer. It works fine but I want to know what query(/code) vector is using so I can add some ...
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2answers
37 views

how to draw coordinates along the lanes using MultiLineString instead of LineString

I trying to draw lines along the path of the lanes on the map using openlayer3 but i am not getting any lines on the lanes there is no error in the developers console as well <!DOCTYPE html> ...
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19 views

GRASS: strange classification output and reject map from “i.maxlik”

I am trying to perform a supervised classification with "i.maxlik". I have three bands: 1) elevation (a dem); 2) reflectance (derived from Landsat ETM+ band4); 3) cumulative solar radiation (derived ...
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1answer
30 views

Intersect elevation interpolated from CAD file in ArcGIS

I have two datasets - contours and vector (water, roads,...) Vector layers were used as breaklines to generate the contours. Then the contours were generalized a bit. For quality check I need to ...
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24 views

GDAL/OGR in C++: Opening a vector file

So I'm making a vector file this way: OGRSFDriverH hDriver=OGRGetDriverByName("KML"); OGRDataSourceH hDS=NULL; hDS = OGR_Dr_CreateDataSource (hDriver, fname_dst, NULL); //I add layers ...
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21 views

Spatial Join Points Vector with Raster Dataset using Arcmap

I have a points file of taxi drop off locations and a raster file grid. I am trying to get a count of each point on a raster cell. How do I go about doing that? It is like I am doing a spatial ...
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32 views

Openlayers snapping not working

I am using a vector layer on my map that contains lines like this: var map = new OpenLayers.Map({ div: "map", layers: [ new OpenLayers.Layer.WMS( ...
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29 views

Detecting features intersecting with Profile Line using ArcGIS for Desktop?

I am using ArcGIS' (10.2) 'Intersect Line' > 'Create Profile Graph' functions (3D Analyst Toolbar) to get cross sections of lines from a DEM raster. Does anyone know, if there is a similiar ...
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1answer
53 views

how do i create OGRSpatialReference from raster file's georeference C++

I want to create .shp file using ogr with georeference based on my raster file, so i create an ogr layer using CreateLayer( "point_out", NULL, wkbPoint, NULL ); i want to set the OGRSpatialReference ...
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25 views

Plunge and trend of vector lines in ArcGIS for Desktop?

Does anyone know how to extract dip and dip-direction (or trend and plunge; dip and dip direction define the spatial orientation of planes, trend and plunge of linear elements) data from a series of ...
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27 views

Polygon to multiline object in ArcMap/ArcGIS Pro

Is there a possibility to create a multiline object from polygon object contours in ArcMap? I found that Edit toolbar allows to create polygons from other shapes, but I couldn't find anywhere an ...
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13 views

Arrangement of vectors and matrix in text file?

My ASCII file has a vector of latitudes, and the indices of those latitude values tie latitude values to the data sharing the same index. That is, if given: latitude[x=0,1,2,3] = 10, 20, 30, 40 ...
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1answer
84 views

Is QGIS Server working like this?

On CentOS 7 I have QGIS Server and QGIS Desktop installed. In QGIS Desktop I created a project with raster and vector data and saved it in a ".qgs" file. Then I copied the file in ...
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7 views

Sky View Factor of building roofs => Vector algorithm [duplicate]

I'm currently working on a project in which I'm trying to assess the SkyViewFactor of a given roof using building vector data. I've already managed to build a process based on vector rasterization ...
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48 views

Aggregate/merge data upon insert into PostGIS (via gdal)

I am working on a project where I take a large raster file (1.5GB+), put it through a number of image-processing operations, and finally convert it to vector data. Being that the raster is large, I am ...
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11 views

How to make coincident a vector layer and a bitmap constructed from Google map tiles using programming

I can make a bitmap file from tiles that I receive from Google map using X_Tile,Y_Tile and Google map zoom parameters successfully.First I use a vector layer to find map extent in UTM,so I have ...
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0answers
22 views

Problem with VectorLayer created in memory

I am working in c++/QT whithnthe qgis API c++ I had to build a personnalized vectorlayout called "TRACKS" , so i write a function that create in memory the vectorlayer like this : QgsVectorLayer ...
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19 views

Vector layers don't seem to be exhibited properly [duplicate]

I'm a veterinarian that uses qGIS for making basic outbreaks maps, and am trying to branch out and expand what I'm doing. When I first started using qGIS 3 years (I believe it was 1.7), ago, when I ...
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21 views

Problem with passing ranks to different buffers

This issue is really troublesome.i have a SpatialPointsDataFrame which refers to a city.I needed to perform a join with a dbf in order to attach the population column which i did thanks to a couple of ...
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0answers
70 views

Converting a (WAsP) vector map to a raster map with GRASS GIS

i'm quite new to GIS and i need to convert roughness data which is available in a vector format to a raster format. The final data should be on a simple 2-dimensional uniform grid with a constant grid ...
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0answers
38 views

Showing/displaying relationship between Earthquakes and Fracking operations?

I am presently analysing the relationship between hydraulic fracture operations and possible associated induced seismicity. I have both the earthquake data (as a shapefile with lat, long, magnitude ...
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1answer
82 views

ArcMap 3D profile graph gives a level line

ArcMap's Profile Graph in 3D analyst works great for drawing a line on the map and seeing the profile. I am doing this part easily; single segments, multiple segments it works fine. However, it is ...
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76 views

NDVI from raster to vector isnt working

I have question...can I make from raster img. vector file via qgis? Because Ive tried it on NDVI image and Ive only got one file with atribut table full of #null. Image is from landsat7... ...
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58 views

OpenLayers vector are not filled

I've a small issue with openlayers vectors. I found an svg marker and I want to change the filling color. I found this example, but it doesn't work with my svg. Here is my example code: <html> ...
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18 views

Performance: Reproject Cache vs. Drawing Vector data in correct projection

I have quite a bit of data that I am caching from UTM to Web Mercator. This is fine, but I have another process that automatically creates map book pdfs. These map books have been setup to read the ...
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94 views

Splitting lines table using point table in PostGIS

My problem is that I want to get the shortest route between multiple point pairs which are stored in a table (PostGIS). In PostGIS I also have a network created using pgr_createTopology on a table ...