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

learn more… | top users | synonyms (1)

-7
votes
3answers
1k views

Delivering map tiles in real-time without caching? [closed]

Is it possible to deliver map tiles quickly over the web without worrying about caching or seeding them? With raster map engines this is a problem because endering raster tiles is resource consuming. ...
1
vote
0answers
13 views

How to create displacement vectors in QGIS using GPS points with different dates?

Is there a way to calculate and visualize displacement vectors in QGIS ? I have DGPS points taken at the same place (ground control points), but their position moved over time as they are located on a ...
2
votes
1answer
291 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 ...
7
votes
2answers
407 views

How to remove long linear strips from polygons?

I have a polygon layer representing impervious land cover. This was taken from a land cover raster dataset. The impervious data represents all impervious surface that is not buildings or roads. I ...
0
votes
0answers
26 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 ...
0
votes
0answers
2 views

Clip & save layer using OpenLayers 2

I ma currently developing a web mapping app. How do I make it possible for my app to clip and save area of interests or area I am working on. I can create a vector layer, modify it and delete if I ...
1
vote
1answer
138 views

Overlapping polygons in the same layer

I am working in QGIS on a vector layer where areas are classified using an attribute "typo". The problem I'm encountering is that many polygons are duplicated or overlapping, with the result that some ...
0
votes
1answer
18 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 ...
1
vote
1answer
40 views

Add feature manually to a vector layer in ol3

I'm trying to add a layer manually to a vector layer with javascript. I can't seem to determine why this is failing: http://jsfiddle.net/Kieveli/f4t6n6v1/4/ I've tried sane coordinates like 16,22, ...
1
vote
1answer
57 views

Automatically changing the angle of a symbol in QGIS?

I am working with an iron age cemetery in QGIS. I marked every grave in a point layer with several columns; amongst others, burial rite (inhumation, cremation etc.). I inserted a second column for the ...
1
vote
1answer
34 views

How to measure the distance between multiple points and multiple polygons?

I'm trying to find a quick and accuarate way to measure the distance between 3 survey sites and all the designated sites within 10km. The survey sites are on a point vector layer and the designated ...
0
votes
0answers
15 views

How can I sync a vector image with a leaflet map?

I am trying to create the following: For the user to interact (hover, click, etc) with vector layers on the left, and have a leaflet map respond to it on the right. I have used the following that ...
1
vote
0answers
21 views

PyQgis - Adding attributes to a POSTGIS layer

After reading @underdark's answer to this question on creating a new vector layer and @Matthias Kuhn's to this one on field calculation, I wrote a script that allows me to calcultate the mean ...
0
votes
0answers
32 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... ...
0
votes
1answer
151 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", ...
1
vote
1answer
68 views

ArcGIS, How do I get smoother contours?

I am trying to get nice smooth contours using ArcGIS. I have already smoothed out the DEM using focal statistics, simplified and smoothed the contours. The current result looks like this, which is way ...
2
votes
1answer
1k views

How to deactivate Vector Selection In OpenLayers wms features

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

Plugin SWAP vector direction doesn't work in QGIS

I've installed plugin Swap vector direction in QGIS. But it doesn't work. I click and nothing. I need to flip lines (22 000 000 lines). In ArcGIS takes many hours and still flipping. I thought ...
1
vote
1answer
25 views

Render or display only the boundary of a vector layer containing thousands of polygons

This might be a very basic question but my lack of experience makes it really hard to answer. To have a cleaner map to print I want to display only the boundary of a layer composed of more than ...
1
vote
2answers
1k 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
1answer
36 views

QGIS - some edit feature options disabled in vector layer [closed]

I created a new vector layer in QGIS, saving as I went along and then I saved the project and logged out. When I went back into the project, I wanted to add some more features to the same layer, so ...
1
vote
2answers
54 views

Configure default styles in LeafletJS

I want to change the default styles for vector layers in my Leaflet version 0.7.3. I can't find anything about that in in the documentation, so I made this hack: map.on('layeradd', function(e){ ...
1
vote
1answer
40 views

Make diagonal grid in QGIS, divide square into squares

I have square polygon which is aligned under some degree and I want to divide this square to, for example, 25 smaller squares, which must be under the same degree in this square polygon. How this can ...
3
votes
1answer
383 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. ...
12
votes
6answers
5k views

Convert GeoPDF to a vector format

I want to convert a GeoPDF that has vectors entity in it to a vector format and preserve the real coordinates of these vectors. The GeoPDF has been exported from ArcMap and has layers in it. I have ...
0
votes
1answer
212 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 ...
1
vote
1answer
27 views

Is it possible to not show node in editing mod QGIS

I actually have a plugin that allows me to draw on a vector layer (I made it based on the FreeHand Editing Plugin). When a mouseMoveEvent is detected, it creates a new point on the vector layer and ...
0
votes
1answer
39 views

Simultaneous multiple vector layer intersection algorithm

Is there an algorithm, you can suggest or recommend, that I can implement to intersect multiple vector layers? I have a few hundred layers I want to intersect and thinking of developing a little QGIS ...
2
votes
0answers
26 views

How to make a model with more than 2 input layers for buffering and merging?

Would it be possible to add more inputs to Buffer and Merge? From what I can see there is a limit of two input layers per both. As far as I know this is possible in ArcGIS's Model Builder but from the ...
1
vote
1answer
24 views

Vector Click Event is not working

Actually I figured out some problems and corrected it. I declared the overlay just outside the init function. So now I got the 'featureselected' event working properly. But 'featureunselected' event ...
0
votes
1answer
61 views

Land cover modifications in different time periods

I have several shapefiles which contain buildings built in different periods from 1948 to 2013. My question is how could I see which buildings for example in were built 1948 but are missing in later ...
0
votes
0answers
32 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> ...
1
vote
1answer
45 views

Country border between two points

I am trying to extract country borders between two points, using Python. The border is a Shapely Polygon.exterior or LinearRing, the start and end points are Shapely Points. My idea is the following: ...
3
votes
1answer
37 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 ...
0
votes
1answer
41 views

joining non-spatial pollution model (csv file) to Qgis

I need help..I have csv file with concentration data but without coordinates. Start of pollution concentration connect with that one point on map. Is there any chance ? Start of pollution ...
4
votes
2answers
143 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... ...
2
votes
1answer
91 views

OpenLayers 3.5.0, clear highlighted feature after removing feature from source

I want the user to be able to delete the highlighted feature. This works well, but the feature is not cleared until I move the pointer outside the feature geometry. I am using the OL 3.5.0 library. ...
2
votes
1answer
130 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 ...
0
votes
0answers
8 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 ...
1
vote
1answer
21 views

Not all polygons removed when cutting from vector layer in QGIS

I have created ten polygons representing lakes on a vector layer, and I am trying to cut them from an imported and re-projected vector layer of administrative districts. When I use the 'Cut with ...
2
votes
1answer
43 views

Vector tiles in ArcGIS

I have a vector map (consisting of several polygons) and I would like to create several overlapping tiles. I did the same for a raster map using "split raster". For the vector map, I created an ...
14
votes
4answers
2k views

Rubber sheeting in GRASS or QGIS

We are in the process of getting our property boundaries corrected and a side effect of this is that we need to move any assets that have been drawn relative to the property boundaries, so they are ...
2
votes
2answers
122 views

cutting and extending one polygon layer in function to the other layer boundaries

I'd like a methodology that can edit my vector layer, extending and cutting the features in the polygon layer "cap_agricola" within the boundary layer "sp_edr", I would like to solve this problem in ...
1
vote
2answers
43 views

How to deactivate the Color Ramp in QGIS graduated vector styling?

I want to display points with different size and I DO NOT want to have a color ramp. Do you know how I can do that?
4
votes
4answers
211 views

Checking if polygon fits inside another polygon using ArcGIS or QGIS?

How do I check if one polygon fits inside another polygon? Furthermore how do I automatically check if one polygon fits in other polygons of my shapefile? I have a shapefile with thousands of ...
0
votes
0answers
51 views

How to get a “clean” polygon after using dissolve in QGIS?

I'm trying to obtain the boundaries of shapefile, thus to clean the inside as a matter of speaking. While I had expected that dissolve while get me a proper polygon, unfortunately it still has some ...
12
votes
3answers
23k views

Extract Raster Value into Polygon Attribute

I have Raster Data for a State which has Elevation Data in its pixels. I also have Vector layer which has the 300 divisions of State. what I need is, I want to get the average elevation value of ...
1
vote
0answers
32 views

Tool, API of or code samples for calculating spatial similarity between Lines

I am migrating a database with a road network to an other external data provider. We have joined our own data about roadworks, temporary speed-limits, etc., using ID and linear referencing on this ...
7
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 ...