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

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2
votes
1answer
32 views

unable to draw polygon without attribute window popping up?

I'm fairly new to QGIS and an trying to draw a polygon via "Adding Feature". When I make the first left click to start, the attribute window pops up instead of letting me continue on with additional ...
1
vote
0answers
54 views

How to automatically vectorize data from WMS?

I am facing a problem, when I have a historic map in WMS layer and I need to get buildings from this map (approx. 2000) to vector layer fo further analysis. Is there any workflow how to ...
0
votes
0answers
16 views

Statistics on matching point layers ignoring nodata values in QGIS

I have a large area and a street crossing this area. Both are vector point layers in QGIS. The large area contains -99 as NoData value. I already created the intersection of both as a new layer. I ...
1
vote
2answers
196 views

Openlayers: Get Start and End Points of Line Vector Features

I'm trying hard to get start and end of lines from a vector. The line vector is loaded from a kml-file. For now, I tried to iterate over features in the vector and grab the start point and put it in a ...
11
votes
2answers
467 views

Moving points onto lines (~neighborhood)

I do have two vector layer, of which one is a point layer based on "events" by remote sensing and the second one is a line layer from local research. In my case these are earthquakes and tectonic ...
7
votes
2answers
515 views

OpenLayers how to maintain layer ordering while using SelectFeature control

I'd like my map to display a few layers in a particular order. Some of these layers are Vectors, others are XYZs, and some of my Vector layers display attribution. Initial layer ordering works fine ...
2
votes
2answers
65 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 ...
1
vote
1answer
87 views

How to indicate flow of a watershed feature?

While tracing and digitizing rivers, streams, rivulets, etc., is it possible to indicate the direction/flow in the shapefile on QGIS? I'd like to avoid using map labels. Ideally, when done tracing, I ...
0
votes
1answer
73 views

Get lat/lon points from image pixels

I need to build an application with the following requirement: shows a map .png picture to user. then, users select several points around the map (I can get the x/y pixels from each point) based on ...
4
votes
3answers
3k views

Openlayers remove previously drawn polygon on starting to draw next one

Objective: At any point of time there SHOULD only be zero/one polygon(s) on a vector layer with a polygon control. I need the previous polygon to be removed as soon as user starts drawing the first ...
0
votes
1answer
65 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
0answers
83 views

Is there a decent algorithm in QGIS Process Modeller to create a grid?

I am using Process Modeller to automate merging several vector layers and then creating a grid to cover the extent of the merged layer. There are functions which already exist which are not listed in ...
1
vote
1answer
75 views

QGIS: Line to polygon conversion

Currently we are working in a geological project..in which all the Contacts, Linear & some other geological features have to be captured. The thing is most of the features have to be Captured as ...
1
vote
1answer
68 views

Stamp out and transfer values from one overlayed vector layer to another

I have a vector layer with administrative boundaries and another vector layer with postal code boundaries, which are more precise/smaller entities/objects. I now want to transmit the values of one ...
1
vote
2answers
101 views

Techniques for Filtering the Attribute Table in QGIS's Print Composer

For the legend of a trail map I'm working on I'd like to show the trails and their lengths. I have this data in the table. The problem is that not all of the features (lines) have a name or length. ...
2
votes
2answers
225 views

Georeference vector linework

I'm new to GIS and a lot of searching didn't answer my specific question so far, so I hope someone can help me here. What I want to do is creating a small web application to visualize election ...
0
votes
1answer
38 views

Select all features close to clicked

I have an openlayers map with more then 20000 features not in wms, only in vector layer. I have a control to select features, but sometimes it's really hard to select, specially the lines, and also ...
1
vote
1answer
53 views

How to Warp vector file based on control points in ArcMap?

I have a very comprehensive polyline file that, when compared with imagery, is obviously offset by a few hundred meters, but the offset varies from one area to another. It would be easy for me to ...
0
votes
1answer
44 views

Producing gradients between shapefiles and using original boundarys as isoclines (lines)

to produce a bathmertical map of a river bed I draw shapefiles showing the different depths based on satellite images taken during different tidal levels (deepest, 2nd deepest, 3rd deepest, shore ...
0
votes
1answer
1k views

How to clip a line layer based on polygons with QGIS?

I have a line layer and a polygon layer. Both files have the same SRS. I want in a new shape file only the lines covered by the polygons. I tried in QGIS the Vector -> Geoprocessing -> Clip ...
1
vote
2answers
30 views

Adding time stamps to animation slides with OSS tools

I would like to create an animation with time lapse values printed on the PNG file. For this purpose I have created in QGIS a vector layer that stores timestamp and temperature value pairs for various ...
3
votes
0answers
48 views

Looking for a mobile app for a field campaign with specific spec

In the frame of an international project in agriculture monitoring, I have to propose a mobile app that will be used as a reference for field working. The minimum requirements of such an application ...
0
votes
0answers
31 views

How to raster vector- and shape-files correctly

does anybody know how to convert vector- and shape-files correctly? Doesn't work with tab Raster/convert/vector to shape files. The output always contains strange input-data (wrong and strange ...
4
votes
0answers
28 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 ...
0
votes
1answer
53 views

why can't i export geometry data from a shapefile?

I saved the layer using "vector save as" box but even when adding GEOMETRY=AS_XY in the layer box, the csv only showed the id and no gemetry data.
2
votes
1answer
70 views

Why do layers appear in the wrong order in QGIS 2.2?

I have a problem with in which order my vector and raster layers appear in QGIS. I have raster that I want to be the background of my other layers (vector). I place the vector layers on top in the ...
0
votes
2answers
73 views

Show only some buildings

How do I show only some buildings? I only need to show 3 cabins in the forrest, but not every house in the whole village around, and the city close by. Maybe some of the symbol buildings in the city ...
3
votes
1answer
194 views

How to sum up all field values in QGIS modeler

I am building a model to generate two zones around a point, a 250m-buffer, and a ring of 250 to 1000m, where i recalculate values from an other layer according to the intersections share. The purpose ...
1
vote
2answers
43 views

Creating Many Uneven Buffers

Qgis 2.2, Windows 7 I am looking to create buffers around city lights (the raster). Currently, I have simple polygon buffers around the point layer (oecdminusa), but this is not accurately capturing ...
1
vote
0answers
33 views

Calculating Percent Overlap Between Distribution Maps

Hello there, I am currently trying to calculate the percent overlap (basically the total amount of overlap where these two species come into contact) between Lithobates catesbeiana (first image) ...
0
votes
1answer
20 views

vector file is used by two mapsets at a time in grass gis

i want to study about vector processing.if a vector file is used by two mapsets at a time, which one will be saved first and why.if a team want to work on the same set of shape files, what is the ...
4
votes
1answer
178 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 ...
1
vote
0answers
146 views

Editing QGIS point layer: retrieve attributes of intersecting line layer

I'm creating a custom editing form using QGIS 2.0 and would like to modify the mouse event when creating a point. I've gotten a start by reading this thread: How to programatically check for a mouse ...
1
vote
2answers
355 views

OpenLayers: WMS layer above select-controlled vector layer?

Is it possible to display an image layer (WMS or Image) above a vector layer with activated SelectFeature control in OpenLayers? The image layer (radar returns) contains only sparse, semi-transparent ...
4
votes
2answers
513 views

Vector Mapping for iOS?

Are there any vector map data providers with API's, that i can use to build my app on iOS natively (not on a webview). Specifically im looking for: For a library/framework that uses existing map ...
0
votes
0answers
45 views

how to easily serve vector layer with extra attributes for openlayers

On a website I'd like to show an openstreetmap with buildings colored by a certain feature (tag). So far I was able to extract the buildings for a bounding box, save them as an osm file and load it ...
4
votes
1answer
138 views

Generating a vector contour map of fictional terrain

Originally I had asked this on the Graphics Design SE but after some realization of the question I was asking, it's probably better to ask it here. I'm making a fantasy world map in illustrator that ...
1
vote
1answer
120 views

CartoDB map in openlayers

Is there a way that i can upload my CartoDB map in Openlayers as a WMS layer or Vector layer. Here is the my CartoDB map link. http://cdb.io/1nxdrpf
0
votes
0answers
27 views

Positional error of line features

Does anyone know how to model the error in the spatial location of a line? I think Survey Analyst extension in ArcGIS had a possibility to construct ellipse errors but it is not available any more. Is ...
0
votes
0answers
34 views

GRASS GIS - v.select- ERROR: bad allocation -

I'm quite new to Grass GIS. I have two vector maps, one of a grid (each grid cell is a polygon) and one of a much larger polygon. I've been trying to select the grid cells that lie completely within ...
1
vote
2answers
98 views

QGIS 2.0 Automatic generation of a vector layer out of a point layer

I am an environmental engineer and the aim of my QGIS 2.0 project is to visualize the results of a sewage water system inspection. In a first step I included the hoppers from a csv file and added a ...
0
votes
0answers
58 views

Turn vector layer in raster layer based on cost

Hy, I am trying to rasterize some vector layers into raster layers and I know this is possible with QGIS by using the rasterize function in the raster menu but I don't know how to do the following ...
1
vote
1answer
69 views

QGIS combine Vectorlayer and Rasterlayer to one shapefile

I have to create some Thematic Maps, especially Choropleth Maps on Matlab. Therefore i've found a shapefile which I can use, but need to draw some lines there. I've imported my shapefile as a Vector ...
0
votes
0answers
58 views

How to achieve labeling in openlayers as Google did?

I am tried to find a solution for my question. Please look the images below. Google Google are awesome!!.. They are doing fantastic technique in labeling part. Please look the marked labels, the ...
1
vote
1answer
99 views

How to automatically transform between base layer and vector layer in OpenLayers

I have a simple example on http://jsfiddle.net/29bsw/ I have a map with an OSM layer as base layer and an additional vector layer. The projection of the map is defined as EPSG:900913 and the ...
0
votes
0answers
222 views

Qgis ver.2.2 can not load osm file

I have download shapefile osm with vector >> osm >> downdload data in qgis ver. 2.2. When i I open osm data,qgis not responding. I hope someone could help me. Thanks
1
vote
0answers
37 views

Is there any GRASS command to measure the distance between a point in rastermap and another in vector map?

I have a question about WinGRASS 6.4.3. Is there any GRASS script command to measure the distance between a point in rastermap and another in vector map? I have a raster map and a vector map. Raster ...
3
votes
1answer
106 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 - ...
0
votes
0answers
24 views

What information, Open Attribute table of stream segment shows?

I have delineated the watershed from DEM data. I have converted the stream segment(raster) to vector lines. In the attribute table of this vector lines, there are 3 columns, CAT, VALUE, LABEL, what ...
0
votes
0answers
31 views

Clip vectors in workspace / map extent (QGIS 2.x)

Good afternoon, I am looking for a way to clip several vector layers within a project or folder (with subfolders) and ideally save them with a name change (suffix / prefix) to a new folder / output ...