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

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2answers
268 views

Interpolation on set of points in QGIS

Is it possible to perform Interpolation in QGIS with input as a vector layer which has a set of points collected following a specified path?
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1answer
107 views

How to change the color of vector layer of QGIS in api?

I'm using QGIS-2.4.0 api to develop app in C++. When I add a vector layer to the app, the vector map's color would be random. I used QgsFeatureRendererV2 to get the geometry type of the layer, my ...
3
votes
1answer
130 views

Calculating distances from points to the centre of cells

I am using QGIS 1.8.0 (using older version because I need the Qmarxan plugin which is not available for 2.4.0). I have a study area that has a vector laying of "planning units", or cells over the top ...
3
votes
1answer
314 views

Show alternating contour lines

Is it possible to show only every other counture line? And how do you do that? (Im new to QGIS Lisboa 1.8.0, but even newer to QGIS Dufour 2.0.1, but have used ArcGIS a bit a while ago, and also ...
3
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4answers
1k views

High resolution and high detail vector GIS coastline product needed

What is the absolute best vector GIS coastline product available globally? I know of a great product for Africa (page 13 of this PDF ...
3
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1answer
220 views

Converting map image to GIS

I’m very new to GIS, and I’ve been reading a lot of manuals and information, but I thought I’d ask a couple of questions here. One of my major hobbies is drawing maps of a completely imaginary ...
3
votes
3answers
224 views

How can I draw squares in PostGIS layers at different angles?

I am trying to draw two squares on a 45-degree angle and then merge them using PostGIS to edit. QGIS can draw squares but only on a perpendicular plane (eg, 0, 90, 180), and I need to be able to draw ...
3
votes
1answer
550 views

Measurement units not returned in project CRS units

I am attempting to calculate area of country polygons using the field calculator. The layer in question is unprojected WGS84, but I have set the project CRS to World Equidistant Cylindrical ...
3
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3answers
815 views

How do I draw on a vector map in GRASS?

I have a vector map that has two lines. I want to have the two connected. Is there a way for me to draw a line to connect the two? I am using GRASS gis by the way. The two lines that I want to connect ...
3
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2answers
2k views

Working With Vector Product Format (VPF) - APIs, etc

I've been looking around the Internet for information about Vector Product Format. I want to put together a project that can read Digital Nautical Chart (http://msi.nga.mil/NGAPortal/DNC.portal), ...
3
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1answer
57 views

Why is QGIS only one label rendering at a time?

I'm new to QGIS, but I'm experiencing what I think is a bug. When I load the qgis_sample_data landcover raster and lakes vector layers, then enable labels for NAMES on that layer, I can only ever ...
3
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1answer
276 views

How to reproject all the vector files in a folder to a particular projection using ogr2ogr?

We have a folder with all sorts of vector files like tab,shp,dxf. Many of the files are in different projection. I would like to convert all the files to EPSG: 4326 and eventually the non-shapefiles ...
3
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1answer
290 views

D3 missing zoom Choropleth + Raster

Following this example and Choropleth from Mike's site I am trying to get: image + vector + choropleth = my map As you can see I lost the zoom capability on the vector layer. I have been trying ...
3
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3answers
167 views

Plotting Geo Points with “by arc centered at” Instructions

A recent Supreme Court decision redefined the legal boundaries of California along the Pacific Ocean: http://www.theverge.com/tldr/2014/12/15/7397085/supreme-court-california-boundaries-map I am ...
3
votes
1answer
148 views

What is the fastest way to digitize features on a map?

I'm currently using QGIS basically to trace a bunch of polygons to show individual ponds from google maps. Some of the geometries can be pretty oddly shaped and using the nodal digitizing tool gets ...
3
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1answer
317 views

Where to get the modern Constellations as a vector File?

Does anyone know where I can get a vector version (shapefile/TAB) of the modern star constellations for the entire sky? Wikipedia has a SVG - ...
3
votes
1answer
149 views

Add more info in the attribute table after executing “Line intersection” in QGIS

I have executed the "Line intersection" tool on a road shapefile. This is under Vector > Analysis Tools > Line intersections. I get an output with attribute table having just two columns: type_1 ...
3
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1answer
579 views

Openlayers vector layer don't draw well on chrome (single tile)

I have singleTiled layer in OL (using chrome). The layer don't draw completely unless I pan the map slowly to the south (here is example how the layer keep drawing itself each time I pan) : ...
3
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2answers
587 views

How to calculate distances between addresses and cities and coast line?

I am totally new to GIS, and so I apologize if my question is not clear enough. My basic problem is the following: I have about 160,000 Danish addresses with longitude and latitude for each address. ...
3
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1answer
201 views

How to calculate the percentage of a Line through Polygons?

I have a straight line which runs through a bunch of polygons, which don't have spacing between them (border to border). Is there an easy way with QGIS to calculate which polygons it passes and by ...
3
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1answer
1k views

adding polygon to database in openlayers

I want to add a polygon to the database. I used the following code. The problem is that I am to able to save in database. Whatever polygon I draw on map it gets save temporary and as soon as I reload ...
3
votes
1answer
416 views

MapServer Symbol with Two Colours

I'd like to symbolise a point dataset with a square (or circle) using two colours. This is useful for displaying values collected on both sides of a road (for example). I created two symbols, a ...
3
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2answers
222 views

Dissolve column based on attribute in another column

I have 3 columns within a polygon layer I'm working with. Column 1 = Landowner, 3 different values Column 2 = Parcel, N different values Column 3 = Management type, 5 different values I would like ...
3
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1answer
490 views

How to access the icon of a feature retrieved from text in a vector-layer?

I`m using OpenLayers to show POIs on a map. These POIs are loaded from a textfile and I`m using a Vector Layer to get it onto the map - works great. Now I want to use the cluster strategy to have ...
3
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2answers
2k views

How to query which features of all vector layers intersect with a given bounds?

I am writing a Openlayers map app, and wondering whether there's a better practice to query which features of which vector layers intersect with a given bounds.. It's certainly not a good idea to ...
3
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1answer
951 views

Why is Openlayers KML-layer undefined when using permalink

I am working on Openlayers to dynamically load KML tracks on map. I want it to load filtered KML everytime map is moved or zoomed based on viewport and zoom level. I got it working with code below, ...
3
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2answers
534 views

Assigning RouteIDs to polyline feature class in ArcGIS Linear referencing?

I have a Linear Referencing Route System in ArcGIS Geodatabase format (polylines with M values) and a separate polyline feature class of short segments (called TMC) that do not have RouteIds ...
3
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1answer
1k views

Openlayers Add features performance for 3000 lines

We would like to implement the function of Addfeature in openlayers to draw lines and push them onto a vector layer, and overlay this layer onto open street map or google map. Those lines are draw ...
3
votes
1answer
4k views

Reproject a vector layer (EPSG:27700) using WFS onto a googlemaps background (EPSG:900913)

I have the following HTML-javascript code and i have problems reprojecting the vector layer (WFS) from EPSG:27700 (British National Grid) to EPSG:900913 (googlemaps). I managed to project the WMS ...
3
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2answers
34 views

How to make a line shapefile converted from a gpx track file display over basemaps such as OpenStreetMap?

I have created a line shapefile from a Garmin gpx track file using QGIS 1.12.3 Lyon. Resultant vector file displays properly with other vector shapefiles. Problem is that created vector file (line ...
3
votes
1answer
32 views

How to combine 2 vector shapes created from raster files

In Qgis 2.12 Lyon, using windows 10 I downloaded 2 raster files from an area of my interest. The rasters were on information about precipitation and evapotranspiration. Each cell had a value. I ...
3
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1answer
49 views

Vector differencing fails in QGIS (due to geometric errors)

I was trying to correct the country shapefile of Uzbekistan for Gas flares: Input layer (the UZB_adm1) differenced by this layer. In QGIS the result was that the overlapping regions - where the ...
3
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1answer
53 views

How to ‘invert’ or ‘reverse’ a vector cutline when gdalwarp'ing a raster?

I have a raster of North America and I'd like to remove the larger lakes from it, replacing them with the same no-data value as the original raster. So I downloaded Natural Earth's 10 meter lakes ...
3
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1answer
75 views

Why can't I clip my Shapefile?

I've tried all of these solutions (How to clip a line layer based on polygons with QGIS?) and still cant clip a shp file. I'm trying to create a coastal shp file for one region (NW France) from a ...
3
votes
1answer
46 views

QGIS Convert bathymetry shapefile from fillable to strokeable

In Java I would like to stroke the bathymetry depth lines instead of filling the area. I'm starting with the Natural Earth Bathymetric Data: ...
3
votes
1answer
108 views

Is the QGIS “Random selection within subset” selecting spatially random or randomly from the attribute table?

I am trying to figure out exactly what is being randomly selected. I have a layer of road segments and I would like it to select a road segment at random within a neighborhood (the subset). This would ...
3
votes
1answer
272 views

Representing overlapping polylines in QGIS

I have several shapefiles representing bus lines with different colors for each segment, however, because the lines are exactly superposed, only the shapefile on top can be seen. Is there a way to ...
3
votes
1answer
151 views

One vector data layer with different styles in QGIS

I have one layer of vector data that I would like to show in two different styles. Is there a way of accomplishing this in QGIS? I've solved it now by duplicating the the vector layer and add ...
3
votes
2answers
103 views

Pyqgis How to merge all the active layers? or layers in the registry?

I was wondering if there is a way to merge multiple layers. I actually would like to merge all layers in the registry programmatically, all of them are point layers and have the same fields. I have ...
3
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2answers
686 views

ArcGIS 10.2.2: How to clip vector data from raster data?

I have two files: National land cover data (raster) HUC 8 (vector files of watersheds) Both are national scale but the HUC 8 takes up a larger geographic region than the raster set so I want ...
3
votes
2answers
156 views

Is there a PostGIS function to get a tangent and normal line?

I'm looking for a function that will return a tangent (and normal) for a LINESTRING in PostGIS. I think this is the 3rd time I've come across the need for this function and everytime, I end porting ...
3
votes
2answers
249 views

Converted GPX file has null values in open attributes

I'm an absolute newbie but I think I'm doing this right. I've got a bunch of .fit files from my garmin. I can use GPSBabel to manually convert these to GPX XML and the map looks fine after the ...
3
votes
1answer
2k views

Display list of OpenLayers Features which are currently visible on screen

I have an OpenLayers map a few thousand Points of Interest. These POIs are Vector Features rendered in a Vector Layer. We are loading the POIs once in order to minimize load on the server. Next to ...
3
votes
1answer
2k views

How to get attributes of overlaying polygon layers by a spatial query?

I am new to QGIS and would like to merge selected data/attributes out of the attribute tables from overlaying vector objects on different vector layers without creating new additional layers. Is ...
3
votes
1answer
872 views

OpenLayers 2.12 + click handler + get the name of the vector

Basically, I add several vector layers (KML content got from jQuery GET) in this way: var layer1Vector= new OpenLayers.Layer.Vector('activeInfo'); layer1Vector.addFeatures(featuresLayer1Vector); ...
3
votes
1answer
1k views

OpenLayers - Vector Layer and Google Maps - vector layer and google layers don't seem to be in sync when zooming on Chrome

I am working with a Google Layer and a vector layer in OpenLayers. I was wondering if anyone else noticed any problems with Chrome displaying Google Maps layers on OpenLayers? It seems that when I ...
3
votes
1answer
476 views

Sum up area left “underneath” polygons in QGIS?

I have an area shape layer and multiple other area shape layers. Now I would like to calculate how much space (square kilometers or percentage of area) of the polygons of this area layer is NOT ...
3
votes
1answer
1k views

geometryType property of Vector Layers in OpenLayers

ORIGINAL: I have a couple questions that are focused around the geometryType property with vector layers. When you create a vector layer you can set the geometryType property to limit the geometry ...
3
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1answer
856 views

How to cache and server pre-rendered vector tiles in pbf format?

I want to serve vector tiles server in pbf format. For that I used Mapnik-vector-tiles which is bundled by avecado. Using avecado_server i can render pbf tiles on the fly using ./avecado_server ...
3
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1answer
122 views

Shifting an entire .las file in Z?

I have a set of .las tiles. I needed to edit one of the tiles in Trimble's Inpho DTMaster to remove some noise. The coordinates are correct in the program, showing a my desired elevation. On export, ...