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

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4
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1answer
206 views

Automatically updating user-edited features in QGIS plugin

I am working on a plugin for QGIS (2.12). It uses data stored in an Spatialite database. When the user creates a new feature, the plugin should: update the feature attribute table (the popup form ...
4
votes
1answer
99 views

Creating shapefiles using textfiles in QGIS

I have a shapefile in QGIS which has polygons in it . There are several other attributes for each feature . I want to add another attribute to each feature . The value for this attribute is available ...
4
votes
1answer
947 views

How to add tree height values to raster / vector data?

I am new to working with raster data and I am trying to teach myself a few things. I have what I think is a simple problem but I can't seem to figure this one out after a few hours of searching Arc ...
4
votes
1answer
392 views

How to horizontally align irregularly shaped point symbol to vector layer in QGIS?

Fairly new to QGIS and searching a method to graphically align my point symbols in the direction of the vector. The symbol represents a water valve in an irregular shape in close proximity to a vector ...
4
votes
1answer
1k views

Splitting lines at a specified distance

Does exist some plugin with it is possible to Splitting lines at a specified distance in Qgis?
4
votes
3answers
11k views

Hover/Popup feature problem

im really having an issue here. I am trying to realise a map where i can hover over the features and they get highlighted (works), then i want to be able to click them (works) , i also want a div to ...
4
votes
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), ...
4
votes
4answers
3k views

Openlayers WFS Vector Layer Rules dont get applied

i have a script which applies rules to wfs.vectors. the script works fine in firefox and all the rules get applied, but somehow when i open the same file with the internet explorer 7 / 8 , only the ...
4
votes
1answer
81 views

How to load multiple vector layers into QGIS' map canvas using python scripting?

I am trying to write a standalone script in python to create a QGIS map canvas. The vector layers I am attempting to load are Shapefiles. Currently, I am able to load each vector layer, add them to ...
4
votes
1answer
67 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 ...
4
votes
3answers
826 views

3d vector and geometry operations in open-source GIS

There is some really good open-source software available to work with 2D vectors. For example QGIS has operations like buffer / clip / dissolve / select by location / join attributes by location... ...
4
votes
1answer
167 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 ...
4
votes
2answers
111 views

How to show labels for all polygons in a layer, even with 'NULL' values?

I have a polygon layer which contain information on property name, number of trees within the polygon, average height, and min- and max height values. My problem is, I want to label each polygon with ...
4
votes
1answer
125 views

Comparison of vector file formats

Does anyone know of a chart or table that would explain the benefits / shortcomings of the different vector file formats, eg. .shp, .gml, .kml, .gdb. It seems that ESRI shape is still quite prolific, ...
4
votes
1answer
424 views

Raster to vector with gaps in Landsat ETM

I need to find size of water area from a raster (jpg) using QGIS 1.8.0-Lisboa. The raster is a Landsat image with gaps of data in it. I used Polygonize, but the output file shows wrong polygon size ...
4
votes
1answer
4k views

Relabel Vector Points in OpenLayers

I have created two labeled vector points on an open layers map. I'm trying to change the label text dynamically. I tried changing the values where the stylemap gets the values from and calling layer....
4
votes
1answer
874 views

How to extract features from a vector layer?

I have a vector file containing the river lines of an area. I want to extract a specific water line from the vector. I used: v.db.select but it only displayed: cat|F_CODE_DES|HYC_DESCRI|NAM|ISO|...
4
votes
1answer
2k views

Sketch event in Openlayers 3 drawing interaction

For drawing Polygon in OpenLayers 2 we could use as follow: function drawEnd(){ ... } function putPoint(){ ... } function sketchModified(){ ... } function cancel(){ ... } var ...
4
votes
1answer
1k 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 -...
4
votes
1answer
264 views

Memory Vector Layer Corrupted?

I was working with a large data set that had data for roads, rivers, railways, etc. all together so I decided to break the different data out so I could label it differently on the map and check each ...
4
votes
1answer
197 views

Suggestions for vector format for contour map

I've been trying to create a contour map of a DEM and I've been running into some technical problems. I want to avoid artifacts, so I'm using a DEM of the entire area. This means the size is rather ...
4
votes
1answer
976 views

Loading a multipoint shapefile in R

This issue has only been raised in the community once, two years ago, to the best of my knowledge. I think it's high time to raise the issue again! readOGR, from the rgdal package, cannot handle ...
4
votes
2answers
605 views

How to delimit hinterland boundaries among multiple city centers?

I need to delimit city boundaries basing on centers'magnitude. CenterA's employment/CenterB's employment = (Distance from centerA to break-point E/Distance from centerB to break-point E)^2. AB=AE+BE. ...
4
votes
1answer
2k views

Split vector layer by field name

I have a vector layer of 108374 lines I want to split the vector layer into field names of the layer, which is 17. Now, I want to create a new vector layer containing one of the field names e.g. "...
4
votes
1answer
2k views

How to use a sld file with Openlayers using OSM data?

My app, made with openlayers, displays building data called from overpass api. var data_url = "http://overpass-api.de/api/interpreter?data=(way[building](bbox);node(w););out body;"; //main working ...
4
votes
1answer
104 views

Reduce number of vector field arrows in qgis

OK, now that I have figured out how to get my vector fields in qgis, I can't figure out how to reduce the number of vector arrows on the map. Is there a setting for how many vectors are sampled? ...
4
votes
2answers
3k views

OpenLayers - Get features inside a polygon

In my OpenLayers map I allow users to draw an ad-hoc polygon vector. Then I need to get all the features from a WFS vector layer that fall within the ad-hoc polygon. Here is the code I have that ...
4
votes
1answer
687 views

Generate centroids for vector polygons based on raster and land-use data using QGIS

Although QGIS has the ability to generate centroids for polygons, I am not sure how to generate centroids based on land-use development using raster data. Here's an example of what I'm trying to do: ...
4
votes
1answer
110 views

QGIS Composer Distorted SVG PDF Output

I've noticed that some SVGs are distorted when outputting to a vector PDF from QGIS. A good example is NorthArrow_07.svg. The image on the left is how it looks in the composer and the image on the ...
4
votes
1answer
141 views

Comparing floor and roof areas using QGIS?

I am pretty new in this GIS topic and I would really appreciate if someone can help me with this problem. I am doing a research for university that shall show the available roof area for ...
4
votes
1answer
565 views

Removing some bands or layers from a tiff using gdal

I have been working on a multiband raster image. It is a pix image. I need to just work on the 26 bands that are raster files and not the 4 bitmaps that are are also included in the pix image. I could ...
4
votes
1answer
553 views

OpenLayers Google v3 and other layers drift apart

I'm stuck. My code works with OSM, but I need it to work with Google as well. The problem is simply that Google v3 and my other layers are not playing well together at all. They don't zoom together. ...
4
votes
1answer
108 views

Extract Z information from different vector layers in ArcMap 10.1

I have 2 different vector layers, Layer A detailing the area of different polygons and Layer B having similar size polygons with z values instead. I would need to combine Layer A with Layer B so that ...
4
votes
1answer
609 views

How to measure the distance of multiple points to a line

I have two shapfile in QGIS to which I am trying to find the distances between. I have a shoreline which is a vector line and then I have hundreds of data points in the ocean. What I am trying to find ...
4
votes
1answer
948 views

How to export 2D vector graphic from ArcScene to Illustrator?

I need to know how to export 2d vector graphic from ArcScene so I can edit it with Adobe Illustrator. I've tried changing the options when I export 2D scene as AI file or PDF file, but they always ...
4
votes
1answer
460 views

Analysing Information By Vector Grid

I have two vector line datasets and wish to compare the line lengths. While I have already compared the sum of the lengths, I'd like to conduct further analysis down to 250m, possibly lower. I'm ...
4
votes
1answer
955 views

How to prepare SVG images for presentation in OpenLayers?

I have a collection of SVG vector images I need to display on a map, probably using OpenLayers/KML. Is there any way to convert a vector image from SVG to KML? Or would it make more sense just to use ...
4
votes
1answer
2k views

GDAL - creating vector from raster

[SOLVED] Good day! I'm looking at either gdal_contour or gdal_polygonize.py to create a vector layer file from a raster file. I can create the vector file using either method, but it's upside down ...
4
votes
1answer
2k views

Extract parcel layers from vector pdf

So, I have an interesting problem... I have a PDF file which has over 100 pages and each of these pages is displaying a map in vector format. By using some third party program I was able to find out ...
4
votes
0answers
92 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 pdf....
4
votes
0answers
67 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
34 views

Projecting polygon when calculating its area? [duplicate]

I have a broad range of polygons (in vector format and in SpatialPolygonsDataFrame class), some going east-west, others going south-north, while even others span polar regions or very large ranges as ...
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 ...
4
votes
2answers
585 views

Unable to select Vector Layer

I am using the following example, to select a vector layer feature on click. The example demonstrates Highlighting and selecting the layer. I was able to successfully implement the Highlighting of the ...
3
votes
4answers
3k views

How to convert a vector map to raster in Qgis?

I am creating a thematic map (vector data) with different classes. How to convert this vector map to a raster map, keeping the classification?
3
votes
2answers
2k views

How to find the middle point of a line in QGIS

I am trying to locate the coordinates of the middle point of a line feature in QGIS. I tried searching online but can't seem to find an easy way to do this.
3
votes
2answers
218 views

QGIS Real-Time Vector Layer Creation

QGIS is running on my Windows PC. I have a CSV file on my PC that is remotely updated with values of a raspberry pi's GPS position and some wifi-status readings. Is it possible to create a vector ...
3
votes
2answers
194 views

Is there a shortcut in GRASS for importing vector files?

Is there a keyboard or command shortcut in GRASS for importing vector files? If you know link where I can find maybe whole list of shortcuts for GRASS, that would be awesome. Thank you.
3
votes
5answers
4k views

Export shp spatial data to Corel

Hi I need an printable administration map of a country. I would like to use it in Corel Draw for some colour manipulations and poster printing. I have found the map on http://www.diva-gis.org/ but it ...
3
votes
4answers
3k views

Scriptable way to merge polylines that join in ArcGIS

I have a number of polylines (around 9000), a number of which have one or both ends touching another polyline. I would like to merge these ones together into one polyline - thus reducing the number of ...