Tagged Questions

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

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0
votes
1answer
44 views

TileStache can't find spatial ref for vector layer

I have a query based vector layer in my TileStache configuration, and it's hitting this block of code if layer.GetSpatialRef() is None and driver_name != 'SQLite': raise KnownUnknown('Couldn\'t ...
3
votes
2answers
356 views

Split Lines at Intersection of Other Lines

I have two line layers (roads and contours in this example) and I would like to split the roads layer every time it crosses/intersects a feature on the contour layer. I can't seem to find a tool that ...
1
vote
1answer
111 views

Iterating over selected features in QGIS Processing

I used to be able to iterate over selected features using the following script in v2.0. import processing features = processing.getfeatures(layer) for feature in features: #Do whatever you need ...
0
votes
0answers
36 views

How to set pen width of rivers based on scalerank attribute (QGis 2.2)?

I have a Vectorlayer from NaturalEarth.com with riverdata that includes "scalerank" information. Now I want to display these with different pen width based on their scalerank, like this: scalerank 1 ...
0
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0answers
20 views

Changing tracks to vectors in a grid

This is a version of a question that I posted on the GRASS list, but I didn't get any suggestions there. I would like to overlay a grid (cell size about 500 m x 500m) over an animal track created from ...
1
vote
0answers
36 views

MapServer: UV_ANGLE not calculated correctly?

I'm following this example given on the MapServer website. But the angle of the raster is incorrect: The data is my grib files is correct, and should not yield these perfect opposite directions. ...
1
vote
2answers
97 views

How to align/georeference distorted vector layers in QGIS?

I've got a shapefile which has been digitized from a strongly distorted historical map, and would like to align it as nicely as possible to another precise shapefile layer. The transformation must ...
0
votes
0answers
16 views

Mapserver dynamically line

I'm a beginner for GIS especially for Web GIS that's implementation to mapsever. I created a project that I've uploaded at dedyfuadi.web.id . For the map features, I made by QGIS 2.0 and for ...
3
votes
2answers
117 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 ...
0
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0answers
40 views

Assign a particular projection for un-projected raster/vector files in a folder/sub-folders

We are having 1000's of raster images/vector (shp,tab,dxf) files in a folder/sub folders. Is it possible to check the projection of those and if it is an un-projected one? WGS 1984 has to be ...
0
votes
0answers
21 views

Is it possible to sort by Layer Name when adding vector data from file geodatabase in QGIS?

Is it possible to order the data alphabetically when adding data from a file geodatabase in the Select vector layers to add... window in QGIS? It is ordered by the Layer ID number, with no way to sort ...
0
votes
0answers
33 views

Finding normal vector to DEM

I have a DEM grid (Surfer, or whatever format) and an x,y position on that grid. I also have a series of depths from the surface. I need to calculate, for each depth, the x,y,z of the projected ...
1
vote
1answer
97 views

How to project vector data in QGIS 2.2?

I'm running QGIS 2.2 on Ubuntu 14.04. Trying to project data gives me a hard time right now. The last time I did that was in 2.0 and I basically changed the projection by saving the data as a new ...
0
votes
1answer
79 views

Produce line from components, length and angle

I have a CSV file, or point data file which includes information about line vectors which I have previously calculated. This file is outlined as such: x, y, dx, dy, length, angle(east_from_north) ...
1
vote
0answers
54 views

Method for identifying upstream segments

I need to add to the attribute table of a stream network layer a column that can identify all upstream segments that contribute to the segment (for each segment). My best idea at the moment is to ...
3
votes
2answers
144 views

Is it possible to add house numbers using the Mapbox Street Vector Tiles source in Tilemill2?

Title says it all. Does anyony know if the house number is included in Mapbox’ vector tiles, and if so how to access it for styling? Thanks for any advice!
2
votes
1answer
35 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
77 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
22 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
309 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 ...
2
votes
2answers
92 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 ...
0
votes
1answer
88 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 ...
1
vote
1answer
140 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 ...
2
votes
0answers
102 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 ...
0
votes
1answer
87 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
88 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

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
50 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
2answers
46 views

Rasterization in different bands

I have a set of vector based shape files, representing different types of ground coverage in a city (for ex: roads, buildings, open field,...). For the algorithm that I want to run on it, I need just ...
0
votes
1answer
47 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
2answers
32 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 ...
0
votes
0answers
34 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 ...
3
votes
1answer
73 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
1answer
57 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
97 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 ...
1
vote
2answers
149 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. ...
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
45 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) ...
4
votes
1answer
229 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 ...
0
votes
1answer
21 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 ...
1
vote
0answers
196 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 ...
0
votes
0answers
57 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
175 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
159 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
1
vote
2answers
64 views

Trace vector map from GeoTiff, Garmin

My goal is to create a vector map for my Garmin GPS by tracing over a topo raster. The vector data would be exported in ESRI SHP format and later converted for Garmin. So far, I can load the geo ...
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
67 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
2answers
117 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 ...
1
vote
1answer
77 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 ...