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

learn more… | top users | synonyms

3
votes
0answers
46 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
30 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
27 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
44 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
65 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
71 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
177 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
40 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
30 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
168 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
118 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
348 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
489 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
42 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
120 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
73 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 ...
1
vote
1answer
104 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
30 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
89 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
1answer
80 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 ...
0
votes
0answers
55 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
65 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
54 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
90 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
219 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
35 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
78 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
29 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 ...
3
votes
0answers
75 views

Joining csv file to vector layer in Processing modeler?

I am trying to join a simple csv file of values to a vector layer within Processing modeler. The match would be on an id held by both files. The csv file has no geometry. I can do this easily in ...
0
votes
0answers
23 views

Show the paths but not roadsides and driveways in the line layer

I want to display paths in the woods but the paths are all in One (line) layer that contains all roadsides, pavements, drivvays, but also paths, tractor road and other relevant roads in, and up to the ...
0
votes
0answers
25 views

How to draw some ellipses that can cover some categorized points automatically in QGIS?

Instead of using Rectangles Ovals Digitizing plugin to draw some ellipses manually, is there another way to draw them automatically that can cover some categorized points in QGIS?
0
votes
0answers
37 views

Zonal statistics won't work after re-projecting vector layer

I have qgis 2.0. I want to analyze raster information within a buffer of 30 miles around a vector layer of cities across the world. However, both the raster and the vector are in WGS84. I have no ...
43
votes
8answers
7k views

How to create Vector Polygons at the same amazing speeds GISCloud is able to render them?

EDIT (outlining new bounty added): I have added the largest bounty possible to this question in hope of getting a very detailed answer. Your solution should outline a step-by-step guide utilizing open ...
2
votes
2answers
157 views

Convert ASCII Grid Colorized to Raster

I have an ASCII Grid file + .prj file and can visualize this in qGIS. I can colorize it by going to properties and using a Pseudocolor Ramp. However, I want to export this now as a TIFF / Raster. ...
0
votes
1answer
99 views

Polygonize(raster to vector) [closed]

I have been install QGIS 2.0.1.when I use Polygonize (Raster to vector)for convert jpg to shp I get error message such as: C:\windows\123.exe is not recognized as an internal or external ...
10
votes
3answers
3k views

How to find and merge duplicate points?

I have two point shapefiles: Red and Blue. Each point shapefile has a z value which represents a radius (i.e. represented as buffers in the example). A duplicate point is defined as a point that ...
0
votes
1answer
26 views

Multiple vertices after editing giving wrong start and end x, y co-ordinates

I have a small problem which I have been fighting to solve but in vain. Initially I generated some polylines across the river at various locations. I found some of them are smaller in size and not ...
10
votes
3answers
9k 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 ...
14
votes
3answers
1k 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 ...
0
votes
0answers
31 views

Shifting Polyline Feature Class

I need to horizontally shift a Polyline feature class (clip1diss) (just one raw) 360 degrees East (deltaX = 360). It would be the equivalent as to "Move" in an Edit session in ArcMap but I cannot ...
0
votes
1answer
34 views

QGIS problems getting layers to line up correctly.

I am trying to add a raster layer and a vector layer to qgis. I have set both of their CSR to NAD83 Oklahoma North State Plane. It doesn't seem to work even with all the files set to those CSR. ...
0
votes
0answers
30 views

QGIS pixel/square cms using scale, dpi

The data (vectors) I'm using are 5cm in resolution. I think that resolution refers to accuracy of the data and not the image resolution. I've produced maps using the QGIS print composer and exported ...
0
votes
1answer
10 views

GRASS Add Vector Point

I need to do a viewshed analysis using GRASS. I've got the DEMs loaded; and I simply want to input several (2-4) points (like 41.12345N, 122.34567W from GPS). What is the simplest, most ...
0
votes
2answers
286 views

How to capture contour lines from OSM cycle map as vector?

In QGIS, there is a plugin to insert a OSM cycle map layer, that brings as an image from http. But I can't convert this OSM Plugin layer to a raster image. I can't even imagine how to get the contour ...
0
votes
0answers
59 views

Cropping elements from one layer to an element from another

I'm trying to make a hex map of a country (Russia, in this case). To do this, I've opened a map of Russia in QGIS (from Natural Earth), set up my projection, and created a hex grid with MMQGIS. So ...
2
votes
2answers
81 views

How can I get repeated vector grid in horizontal direction?

I need to get repeated vector grid layer in horizontally direction. I created many polygon vector grid layers, and their extents as listed bellow (Xmin-Ymin, Xmax-Ymax): Layer 1: 5910000 3040000 ...
0
votes
0answers
83 views

changing unit of area from unknown unit to square meters

I am using Qgis 1.8 and I have this polygon.Now I wanted to know the area of this polygon and i have used field calculator and it shows my area as 651692439.under general tab crs is : EPSG:4326 - WGS ...