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

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1answer
5k views

Openlayers wfs vector layer

I'm trying to add a vector layer with a wfs layer and it's not working.Can anyone point a solution? Openlayers code: var wfs = new OpenLayers.Layer.Vector( "Stavros Features", ...
6
votes
2answers
1k views

Does an openlayers vector layer work across browsers?

I was under the impression that it was. Here is my example: <html lang='en'> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> ...
6
votes
2answers
457 views

Convert points to lines with Python GDAL

I have a dictionary with points. The points are derived from a raster (see image below). The points are not sorted and are not in order. The dictionary looks for example like this: pointDict = {0: ...
6
votes
2answers
617 views

How to check whether a layer is vector or not in OpenLayers?

am not sure whether this is a stupid question or not.. but I am wondering how to dynamically check whether a layer object belongs to OpenLayers.Layer.Vector class. Thanks for any replies!
6
votes
3answers
5k views

Finding nearest raster cell value based on vector point?

I have two layers in ArcGIS: One is a vector point and the other is a raster layer. I want to append the value of the raster data grid to the vector point. The problem is the vector point is away from ...
6
votes
1answer
799 views

Easily calculate “roundness/compactness” of a polygon

I am trying to find ways to quantitatively describe the shapes of various polygons. For my project, these polygons represent lakes, rivers, lagoons, and parks. So they can be almost any shape. One ...
6
votes
1answer
1k views

Where can I find a Unesco World Heritage List as boundaries?

I was wondering if anyone knows where to find the UNESCO world heritage list with boundaries? I can extract point data from the json feed for the map on the website http://whc.unesco.org/en/list via ...
6
votes
1answer
4k views

How to create a point along a line given distance

I have been given a non-spatial database which contains the names of lines which I have a shapefile for. The database also has names of points and the distance of each point from the origin along the ...
6
votes
1answer
220 views

Fast data representation on the vector layers

I have found an interesting article about how HTML5 supports representation on large datasets. Article can be found here. In the article it is said that HTML5 and feature simplification can ...
6
votes
1answer
412 views

How to use simplify()

i have my Vector Data saved in a PostgreSQL PostGIS enabled Database. The Data im displaying is very detailed, i want to simplify it through the simplify() method of Postgis. I duplicated one of my ...
6
votes
1answer
2k views

How can I programatically create and add features to a memory layer in QGIS 1.9?

I had a working plugin in QGIS 1.8 which read data from an MSAccess database and added it to a series of memory layers. There is some processing involved in the interim so I don't think simply using ...
6
votes
1answer
198 views

Assigning costs to a road network : use raster or vector?

I have a road network in a PostGis database (db_routing). In another database (db_environment), I have some spatial features of the surrounding environment (trees as points and water bodies as ...
5
votes
1answer
446 views

How to determine optimal windmill placement to maximize production?

How can I add automatically the maximum number of points (dots) with 6m diameter and 100m distance each point from other into an area. The dots will present the windmill base (6m) and I want the ...
5
votes
1answer
874 views

Programmable buffers using GDAL and python

Is there a way to programmatically generate buffer layers for vector layers using GDAL and python?
5
votes
3answers
3k views

Creating a raster surface of overlaps from vector polygon shapefiles?

Basically what I'm trying to do (in ArcGIS 10) is to compare three vector files in order to create a 'comparison' raster layer. I tried using Data Comparison (under Data Management tools) but it ...
5
votes
2answers
5k views

How to clip a vector feature to the extent of an existing raster dataset using arcpy

I have a clipped raster dataset with polylines (from the contour tool) overlayed (see attached). I am trying to clip the polylines to the extent of the raster dataset, which seems simple enough, but ...
5
votes
1answer
214 views

Merging and joining two line feature classes while maintaining attributes from both using ArcGIS for Desktop?

I created an event layer using the MAKE ROUTE EVENT LAYER tool based on anticipated scheduled events. The road layer which is the base layer is intact. What I would like to achieve is combine layer ...
5
votes
1answer
296 views

Help with grid creation in QGIS

I have 235 raster tile 20km x 20km. I need to create a grid to overlay across them...ie the grid itself will be 20km x 20km, with the lines of the grid on the boundaries of the tiles. I am assuming ...
5
votes
2answers
524 views

Distribute points respect to features using Quantum Gis

I want to know if there is any tool to make points with respect to selected features in a theme? Using: vector, investigating tools, regular points you can do it but not with respect to a selected ...
5
votes
2answers
187 views

Vectorize cell boundaries in GRASS

I need to vectorize the cell boundaries of a raster map and I have forgotten how to do this. For instance, if I have a raster map of a region that is just map=1 with a cell size of 500m, I would ...
5
votes
1answer
869 views

Create a new vector layer that fills space between other polygons in QGIS

I inherited a clipped (500m radius) land cover map containing vector layers of different land cover categories such as buildings, grass, roads, etc from a colleague. The empty (white) space in ...
5
votes
1answer
231 views

How to cache PostGIS views?

Does anyone knows if there exists a caching system for views or queries in postgis? I have a system that gives information through a webpage using a postgis view as backend. The problem is that, ...
5
votes
1answer
147 views

GDAL/OGR Determine if dataset is raster or vector

I am writing a script using the GDAL/OGR Python bindings and it is possible that the user may provide a raster dataset or a vector dataset as input. If the user provides a vector dataset, the script ...
5
votes
3answers
1k views

How to update feature positions with clustering in OpenLayers?

I have an OpenLayers 2.12 map with a vector layer with a cluster strategy. All the static behavior is how I want it. Now I'd like to add the possibility to update the features' position. I do this ...
5
votes
3answers
6k views

Free Mercator, Vector Maps

Are there any free, vector, mercator projection maps available online? I'm not wanting satellite imagery, but more a stylized map along the lines of this: However, I need it to be vector-based such ...
5
votes
1answer
159 views

LiDAR Feature extraction specifications/standards

I have vector data representing forests/trees/buildings that have been automatically extracted from LiDAR data. I am looking for specification/guidance for LiDAR derived products, or any standard for ...
5
votes
1answer
514 views

Converting polygon values to a vector grid using PostGIS

What is the best way of converting a value from irregularly shaped poylgons to a polygon grid using PostGIS? I have a set of polygons that look like this: and I would like to overlay a grid on ...
5
votes
2answers
233 views

How to download Leaflet vectors in GPX format?

I would like to use the leaflet.draw plugin to allow users to digitize vectors on the map. At the end the data should be downloadable as a GPX-file. Is there any sample that shows how this can be ...
5
votes
1answer
4k views

Trouble exporting from QGIS to Illustrator

I am having trouble getting my files to transfer or export to a vector file. When I open the file in Adobe illustrator there is a lot of information missing. I have tried to "save selection as a ...
5
votes
1answer
160 views

Grid Analysis from samples data

I'm trying to analyze set of samples into vector grids in order to generate average data in corresponding grid.I'm working with 50m separated grids but the size of grid may change over time.That's why ...
5
votes
1answer
587 views

How to emulate a specific vector grid in QGIS?

I would like to analyze data included in a pdf file. The file contains information on characteristics of 16km grid cells for a specific study area. The file also includes a map displaying the grid. I ...
5
votes
1answer
604 views

Vector Building Footprint Resources - Tokyo

I typically know where to look for this data in the United States, but I'm at a loss when looking for building footprint shapefiles abroad. I thought I could find what I was looking for with Open ...
5
votes
1answer
1k views

fTools-Error: “…invalid geometry…”

I want to intersect contours with polygon like in the image below. But i got this error: Warnings: GEOS geoprocessing error: One or more input features have invalid geometry. Some output geometries ...
5
votes
2answers
4k views

Easy way to Create Vector Grid polygons?

We're currently using MapInfo & MapBasic to analyze daily tests results for planning purposes.For each test,exported result may contain empty values (say 999,we know Mapinfo has no NULL values),so ...
5
votes
1answer
978 views

How to draw or edit curved lines in free GIS?

I'm searching informations about drawing simple curved arrow lines into free GIS like QGIS, in this problem data geometry is CIRCULARSTRING ( a type which exists in latest postgis version) It seems ...
5
votes
0answers
80 views

How to compare two sets of points in QGIS?

I have two point layers with XYZ data; one set are points measured in the field and the second set is a Lidar data set. I want to check the accuracy of the Lidar in comparison to the measured data. ...
5
votes
1answer
953 views

Distance Matrix tool in QGIS. How to get result in metric? [closed]

I'm trying to calculate the distance between points in layer with distance matrix tool. And keep getting strange results no matter what. Like this MASTER ------------SLAVE ---------------- DISTANCE ...
5
votes
0answers
54 views

How are the edges of a polygon defined? [duplicate]

Possible Duplicate: Are long lines in shapefiles to be considered geodesics or straight lines in the 2D latlong space? In various representations, such as shapefiles and kml, polygons are ...
4
votes
2answers
6k views

How to connect OpenLayers to PostGIS data?

I have read in OpenLayers how to load KML, GeoJSON etc. vector files in OpenLayers. But how can I connect to PostGIS data. If not, why should I upload my data to PostGIS then instead of directly ...
4
votes
7answers
998 views

Any Good Map Rendering Engines for SqlGeometry/SqlGeography

Can anyone suggest good map rendering engines for MS SQL Server Spatial types (SqlGeometry/SqlGeography)? By rendering, I mean plot the geometries to a common image format such as png or jpeg with ...
4
votes
5answers
3k views

Problems merging DEMs or other raster datasets? Clipping Raster dataset to vector line?

I have two DEMs that I am going create a hillshade from, and ultimately want one hillshade clipped to a county boundary. I am running into a couple problems, though. When I try to merge the two ...
4
votes
2answers
314 views

Vector Analysis: Determining area of county land mass without water features

Here are the layers that I have: State / Province polygon file (With Area Field) County / Ward polygon (with no area field), but all the polygons are within the state boundaries Water ways for the ...
4
votes
3answers
2k views

How to calculate orientation of line segments using open source GIS?

I'd like to calculate the orientation of line segments relative to north direction using open source tools. Which tools or functions would you recommend?
4
votes
2answers
152 views

Self-hosting Mapbox vector tiles

As presented in a talk at FOSS4G Mapbox Studio allows to create Mapbox vector tiles and export them as a .mbtiles file. The mapbox-gl.js library can be used to dynamically style and render Mapbox ...
4
votes
3answers
141 views

Can you recycle shp and shx files in shapefile fishnet (vector grid) where only dbf data changes?

I'm periodically getting data from an external partner that is bound to a very large fishnet (vector grid) in shapefile format. The fishnet itself sits at around 400~ megabytes, but the only data that ...
4
votes
2answers
3k views

Reclass for vector data in ArcGIS

I've got a vector dataset (in fact, OS MasterMap data) and I want to set the value of a certain field based on the value of another field. For example: Field1 Field2 Building 20 Grass ...
4
votes
4answers
1k views

How to get vector data from OSM to use in QGIS?

How do I get data from OpenStreetMap which I can then edit in QGIS layer by layer? What is the best OSM output and what / how do I get to a suitable input for QGIS? OR...is there another appraach to ...
4
votes
1answer
2k views

Google maps android vector rendering : how do they make it that fast?

Most of the question is in the title. If you are on android (I believe its the same on IOS) and use maps you will notice the quality of the maps app and how the vector maps are drawn in a very fluid ...
4
votes
4answers
5k views

Merge overlapping lines in ArcGIS

I have a polyline shapefile containing a number of lines, some of which overlap. By overlap, I mean that they follow exactly the same path for some of their route, but also have bits that are not ...
4
votes
2answers
165 views

Problem overlapping shapefile and vector in R

I want to plot a shapefile over a raster file in R but I can't make them overlap perfectly: the raster appears to be rotated of few degrees counter-clockwise. Is it a problem with the projection? ...