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

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2
votes
1answer
241 views

pyQgis in stand alone script, vector loading error

I am trying to use the Qgis functions in a stand alone Python script. I m running Mountain Lion OS, 2.7 Python & the Qgis 2.0.1 Dufour. My main problem is that I cannot get started - I cannot ...
1
vote
0answers
16 views

OpenLayers - Add points at vertices of line while drawing line

I would like to create points while I draw a line on my map in OpenLayers. That is, at each vertices of a line and at the end points there is a shape like a square, circle, or diamond. I have this ...
1
vote
0answers
17 views

Openlayers text symbology is not being shown

I have a Vector Layer in a .json file: { "type" : "FeatureCollection", "features": [ { "type": "Feature", "properties": { "Station_Id":107, "NAME":"ARDEBIL(F)","ELEVATION":"1314.3"}, ...
1
vote
2answers
607 views

OpenLayers vector does not draw (or re-draw) on zoom level change or layerswitcher off/on

Here is the full code (i'll highlight the important parts after): jQuery(document).ready(function($) { // ...
1
vote
0answers
30 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 ...
1
vote
0answers
28 views

Clipping between features within a single vector?

Is it possible (via the Qgis API and friends), to clip polygonal features within a single vector layer? The hope is to accomplish this without having to duplicate the feature into a new layer. ...
1
vote
1answer
42 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 ...
0
votes
1answer
91 views

Invalid geometry message when using Difference tool

I am using the Vector \ Geoprocessing \ Difference tool to get the resulting area when taking a) current ground disturbance away from b) historic total ground disturbance to give c) what has been ...
2
votes
1answer
43 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 ...
3
votes
2answers
65 views

Merging raster and vector not working

I have 1 vector layer (counties) and 1 raster layer (population density). I have tried merging these two, so that I can examine population density within a county, but I have had no luck. It just ...
0
votes
0answers
7 views

OpenLayers.Layer.Vector - addFeatures() weird behaviour

I have noticed that the addFeatures() of the OpenLayers.Layer.Vector add a lot of features and not just the feature that we pass to the function: var vectorLayer = new ...
2
votes
1answer
53 views

Update Attribute based on spatial location

I want to spatially (Spatial Join) update few fields, not all, from another feature class. Is there any way to select and update few fields instead of all the fields from the other layer and ...
0
votes
1answer
167 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 ...
2
votes
1answer
214 views

Creating buffers that will not overlap in QGIS

I am dealing with a .shp with a number of points in it. The distances between points range from ~300m to 5km. I wish to create a 1 km buffer around each point with as little overlap as possible. Each ...
2
votes
0answers
25 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 ...
4
votes
2answers
46 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 ...
1
vote
0answers
18 views

Create vector layer from feature collection in OpenLayers

I have used a WPS process gs:UnionFeatureCollection to compute the geographical union of two collections of WFS vector features. The process returns a collection of features which I intend to display ...
7
votes
2answers
372 views

What does vector tiled map mean?

I'm working on an application that renders geoJSON into OpenLayers map. The idea is about not having PNG images downloaded from external services (OSM or Bing) but having geo information in geoJSON ...
1
vote
2answers
33 views

How to show average walking distance to closest point in census tract in ArcMap?

Given a map layer of point locations, and a second map layer of census tract polygons for the same area, how would you create a map layer that shows the average walking distance to the closest point ...
1
vote
1answer
30 views

How to crop a vector shapefile according to raster?

I am trying to clip a vector shapefile- points according to a DEM in QGIS. I used GDAL function and polygonized the DEM. Then I ran the Vector-Geoprocessing tools-clip in order to crop the vector data ...
0
votes
0answers
15 views

QGIS merge selected features tool malfunctions due to geometrical errors [duplicate]

The issue occurs using the 'Merge Selected Features' tool when there are geometrical errors in the features (not all are picked up by the 'check geometrical validity' tool). In 2.2 Valmeria, the ...
3
votes
2answers
1k 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), ...
2
votes
1answer
29 views

Extract all raster cells outside a polygon

How does one perform the very simple task of extracting all raster cell values outside a polygon? I've been looking through QGIS for hours with no solution to this simple problem.
3
votes
2answers
104 views

Add rectangle polygon

I have a polygon shapefile layer. I want to add a rectangle polygon (just like in Arcmap), and another one using the previous polygon edge. I need it to be accurate, my hands do not meet this ...
2
votes
3answers
104 views

Generating a polygon tile index from multiple vector datasets

OK. well this is silly, in that there is no way it should be as difficult as it has been for me to find information regarding how to generate a polygon tile index from multiple vector (contour) tiles. ...
2
votes
1answer
26 views

OpenLayers - cannot set layer opacity

I have the following problem: by default, you can simply change the opacity of layer by writing for example: layer.setOpacity(0.3); But when I add it to my map SelectFeature controls, my layer is ...
1
vote
1answer
32 views

Deleting vector lines beyond image extents using QGIS?

I am using QGIS 2.2 I have one vector line layer (roads) that stretches beyond my base image (see below). I wish to have the roads "clipped/trimmed or deleted" right at the edge of the image's ...
2
votes
1answer
1k views

How to deactive Vector Selection In OpenLayers wms features

This is my sample code and work fine :), But I have a little problem, I'm using multiple layer (WMS), when I zooming the layer will be shown or hidden. In my example bellow when OpenLayers level zoom ...
1
vote
0answers
29 views

Vector layers without geometry in QGIS?

Using QGIS, I have set up a couple of automated layer additions via the toolbar. After adding geometry in each respective layer (point, lineString, polygon) and saving changes to the layers, the added ...
0
votes
1answer
62 views

How to perform an attribute-weighted sum of multiple polyline features from a single vector layer?

I have a shapefile of ~8000 polyline vector features representing traffic journeys on road routes. Each has an attribute representing volume of traffic for that journey. The routes are all generated ...
1
vote
1answer
76 views

map can only have one feature, after user click

I'm using openLayers 2.13.1. I have a map wih a vector layer and Editing tools. I want the map to have only one feature even if the user keeps adding. So I want the new feature to automatically ...
3
votes
1answer
174 views

How to create a line layer which connects a point layer to a line layer?

In the map shown below, I have manually created the dummy lines (in green). Using python, and without using PostGIS or sextante, I would like to automate the creation of these dummy links between a ...
1
vote
0answers
14 views

Vector Layer Symbol (ism) properties?

I would like to streamline the render of a polygon grid vector layer as a simple line (no fill) via Python coding. I am I bit confused by the implementation referenced by the API. Is it possible to ...
0
votes
1answer
376 views

Draw order (zIndex) of OpenLayers polygons and points in the same layer

My question is similar but slightly different from this one: http://stackoverflow.com/questions/5003349/openlayers-vector-features-z-indexing I have an OpenLayers Vector layer which contains polygons ...
1
vote
1answer
48 views

How to batch-process attribute tables in QGIS (or GRASS)?

I'm using GRASS 6.4.3 in Linuxmint 16. I have a bash script for GRASS which I use to process almost 300 raster files. The script first imports some raster files (r.in.gdal), then does some ...
1
vote
0answers
62 views

How to create a rainfall raster from rainfall contours?

I downloaded a free rainfall data from the Philippine GIS Data Clearinghouse (PhilGIS) which are vector lines. How can I extract the data points from this? I want to extract it because i will be ...
1
vote
0answers
34 views

Polygonize Missing Polygons

Polygonize is not capturing all of the pixels in an image that has been converted to 0s & 1s. The pics below show -original geotif -geotif recalculated to 0s & 1s -polygonize output As the ...
1
vote
2answers
60 views

How to convert Direction Of Travel OSM vectors from a “system” to another?

I have a painful doubt according Direction of Travel (DOT) vectors in OSM data. I'm using ArcGIS10, and a OSM data shapefile. I have a OSM road layer, that has many "Both ways" vectors and many "One ...
5
votes
2answers
4k 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 ...
0
votes
0answers
150 views

How to convert Raster to points in MapInfo?

I wanted to convert Raster data to point data in MapInfo.Does there any tool to convert? can anyone help me?
0
votes
0answers
59 views

How to create a vector layer from a GeoAlchemy2 query?

I'm currently developing a QGIS plugin where I mapped a PostGIS database via GeoAlchemy2. I wrote a function that returns results from a GeoAlchemy query but have no idea how to create a vector ...
1
vote
0answers
20 views

How to compare two sets of points in QGIS?

I have two point layers with XYZ data: 1 set are points measured at the field and the second set is a Lidar data set. I want to check the accuracy of the lidar in comparence to the measured data. Is ...
0
votes
0answers
35 views

Polygonize only pixel values of 1 from a raster

I have a raster mask that I have created in QGIS (2.2.0) that consist of 0, 1 and nodata values. I would like to end up with a polygon dataset that consist of only the value of one pixels from this ...
0
votes
1answer
101 views

Geomedia WebMap WFS to vector marker layer in Openlayers

Looking for minimal example/advice on getting a WFS service to show up as a vector layer with markers/icons in Openlayers map. I have created the WFS service in Geomedia WebMap 6.01.11.19 and the ...
2
votes
3answers
136 views

Creating a Slope Map Using Contours

I am trying to create a slope map. I have many contour elevation files. I tried to use the slope tool in Arctoolbox, but it calls for raster files and I'm working with vector data. Any help with this ...
0
votes
0answers
30 views

QGIS Rasterization of points

I have a point vector layer and want to make it a raster. Trouble is that many points are very close to each other, so unless I specify a very small resolution of the raster cells, likely several ...
0
votes
1answer
32 views

Process to georeference corners of vector file?

I am new to QGIS and trying to wrap my arms around it so please bear with me. I have vector files (DXF) that I need to add back in the georeferencing. They were edited with Illustrator so I loose ...
8
votes
2answers
262 views

Creating an “average” polygon

I found this thread in the old ESRI forums with the same type of problem I am facing today. The solution to the problem is explained in little detail and since I am not an expert, I was wondering if ...
0
votes
0answers
8 views

Adding (ir?)regular vector points

I run 2.0 qgis. (I am quite the rookie) I would like to add a point layer which is regularly spaced every 5 metres along the x-axis, and regularly spaced every 1m along the y-axis. I cannot seem to ...
3
votes
2answers
190 views

Creating catalog of vector layers using ArcGIS Platform?

Is there a way to create a catalog of vector layers in ESRI? We have thousands of tiles of 25cm contour data which we need to individually find and add to maps. It would be so much easier if there was ...