A coordinate-based data model that represents geographic features as points, lines, and polygons.
13
votes
3answers
8k views
How to clip a raster with vector boundaries?
I am using QGIS. I would like to clip a raster precipitation layer using an admin boundary layer that is vector data. However the geoprocessing tools seem to be usable only for vector data. How can ...
4
votes
4answers
1k views
How to split a vector in equal smaller parts in QGIS or similar?
i want to divide a shapefile with many tiles into a lot of smaller tiles.
I am searching for a smart solution, because manual edits are out of questions
Anyone can help or know a nice function?
6
votes
1answer
2k views
How to create a point along a line given distance
I have been given a non-spatial database which contains the names of lines which I have a shapefile for. The database also has names of points and the distance of each point from the origin along the ...
22
votes
6answers
28k views
What are Raster and Vector data in GIS and when to use?
What are raster and vector data in the GIS context? In general terms what applications, processes, or analysis are each suited for? (And not suited for!)
In answering someone's question today, I ...
13
votes
6answers
4k views
Nearest neighbor between a point layer and a line layer
I've asked this question several times on stackoverflow and irc between #qgis and #postgis and I also tried to code it or implement it my self in postgis with no real answer.
Using programming (most ...
6
votes
4answers
1k views
How to georeference a vector layer with control points?
I have a non-georeferenced vector layer that I need to be georeferenced. With raster layers the task is easy and straightforward, but I have no idea what should I do with my vector layer. I have a few ...
5
votes
3answers
5k views
How to convert a vector layer to raster?
In qgis in the raster menu there is an item "convert vector to raster".
This behaves strangely - I do not understand how it is supposed to work.
I can select a vector file, an attribute and an ...
6
votes
1answer
2k views
Openlayers wfs vector layer
I'm trying to add a vector layer with a wfs layer and it's not working.Can anyone point a solution?
Openlayers code:
var wfs = new OpenLayers.Layer.Vector(
"Stavros Features",
...
3
votes
1answer
203 views
How do I find vector line bearing in QGIS or GRASS?
How can one extract the bearings from a set of lines in a vector file?
I'm trying to find the bearings of several straight vector line segments (simplified contour lines, actually) and can't figure ...
1
vote
2answers
370 views
Is it required to use BBOX strategy with WFS protocol in OpenLayers?
is it a must to use BBOX strategy with WFS protocol in Vector layers ?
I cannot display this layer without BBOX strategy:
vLayer = new OpenLayers.Layer.Vector("Test", {
styleMap: new ...
13
votes
3answers
961 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 ...
17
votes
3answers
392 views
How can we protect GIS data?
I have found a very interesting paper here related to this topic.
I just want to have views/ideas from other professional about how we can protect GIS data using Cryptography or Digital Watermarking?
...
9
votes
1answer
520 views
How to access feature classes in file geodatabases with Python and GDAL?
I am trying to access a vector dataset in a ESRI File Geodatabase using Python + GDAL.
I have successfully compiled GDAL with the file geodatabase API. The FileGDB driver is working correctly since ...
11
votes
3answers
2k 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 ...
8
votes
2answers
3k views
How to Import SVG into GIS?
I have a PDF file, with a Map as a vector graphic. I want to get this into GIS. (I use ESRI's ArcGIS, but any FOSS solution is also fine).
I know that it is not possible to directly get the PDF into ...
5
votes
3answers
2k 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 ...
3
votes
3answers
110 views
How can I draw squares in PostGIS layers at different angles?
I am trying to draw two squares on a 45-degree angle and then merge them using PostGIS to edit. QGIS can draw squares but only on a perpendicular plane (eg, 0, 90, 180), and I need to be able to draw ...
35
votes
7answers
5k 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 ...
41
votes
6answers
990 views
Are there any attempts to replace the shapefile?
Recently I've been spending a lot of time converting perfectly good field names like "Percent of citizens age 25 and over with a bachelor's degree or higher" into things like "edbchogtr" to meet the ...
9
votes
1answer
7k views
Programmatically creating a vector feature in OpenLayers
I want to create a vector feature, programmatically, on my map. It's supposed to be in the A4-paperformat, for showing a sort of print preview.
I've created a control for handling this, but now I'm ...
14
votes
2answers
273 views
Toward a protocol for encoding vector data as image
This is a follow up to this question: How to create Vector Polygons at the same amazing speeds GISCloud is able to render them?
In his answer, Yagi outlines a rationale for encoding geographic ...
11
votes
2answers
876 views
Tiling Vector data without losing geometrical and topological information
I am trying to figure out a way to sub-divide a vector based map into smaller blocks. I can tile the map based on different strategies such as q-tree. However, it is unavoidable to cut some polylines ...
6
votes
3answers
616 views
30,000 data points… can this be reasonably served using openlayers?
I'm trying to tackle a web GIS problem and need to figure out the best strategy. I have a map with 30,000 cells on it forming a grid for the province of Alberta. I have a list of data points for ...
4
votes
3answers
1k views
How to calculate orientation of line segments using open source GIS?
I'd like to calculate the orientation of line segments relative to north direction using open source tools. Which tools or functions would you recommend?
5
votes
4answers
2k views
How to calculate polygon length and width using open source GIS?
How can I calculate the length and with of polygons using open source tools?
By "polygon length" I mean the length of the longest line within the polygon (update: to be correct, I just need the ...
4
votes
1answer
100 views
Help with grid creation in QGIS
I have 235 raster tile 20km x 20km. I need to create a grid to overlay across them...ie the grid itself will be 20km x 20km, with the lines of the grid on the boundaries of the tiles.
I am assuming ...
4
votes
3answers
3k views
Find the nearest raster cell value based on a vector point
I have two layers in ArcGIS: One is a vector point and the other is a raster layer. I want to append the value of the raster data grid to the vector point. The problem is the vector point is away from ...
6
votes
1answer
152 views
Finding largest number of observations within a given radius
I have the following problem: Given the location of insured properties (say houses with fire insurance), i have to find the largest sum of insured values which fit into a 300m radius. Now, my first ...
5
votes
3answers
2k 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 ...
5
votes
2answers
418 views
Distribute points respect to features using Quantum Gis
I want to know if there is any tool to make points with respect to selected features in a theme?
Using: vector, investigating tools, regular points you can do it but not with respect to a selected ...
4
votes
2answers
249 views
Spatial query of raster data
I have population distribution data as a raster layer and exposure contours as vector (polygon) layers. What I'd like to do is use the vector layer to estimate the population indicated from the raster ...
4
votes
3answers
3k views
Customizing Popups in Openlayers
Is it possible to customize the shape of popups in OpenLayers? For example, I am creating a pop-up using the following approach:
var popup = new OpenLayers.Popup.FramedCloud(
"popup",
...
4
votes
7answers
705 views
Any Good Map Rendering Engines for SqlGeometry/SqlGeography
Can anyone suggest good map rendering engines for MS SQL Server Spatial types (SqlGeometry/SqlGeography)? By rendering, I mean plot the geometries to a common image format such as png or jpeg with ...
2
votes
3answers
555 views
Cut many lines with many polygons: Too much for my CPU/RAM?
I have a line-shp (80mb) and a polygon-shp (5mb) and want to intersect them. In result, the lines (contours) should be cut by the polygons.
After using one of the tools "Vector -> Geoprocessing ...
1
vote
0answers
45 views
Add regular points to each polygon in QGIS [duplicate]
Possible Duplicate:
assign and move centroids to their polygons
I'm trying to find out a method to define a unique ID based on specific coordinates for each polygon of a shp. The problem is ...
1
vote
1answer
161 views
Why are layers not lining up with others with the same CRS? [closed]
I am creating a project on the UK and have downloaded various shapefiles. When I add a vector layer they are coming up as if they are not lining up. Some layers are nicely on top of each other with ...
1
vote
2answers
1k views
How to set cell size for vector to raster conversion in QGIS GRASS plugin?
I'm converting a vector (loaded in GRASS plugin in QGIS (1.7.0.-wroclaw) and would like to convert this to a raster with a defined cell size. At the same time I need a value from the attribute tabel ...
1
vote
1answer
705 views
How to select a raster file that is under a polygon in a vector file?
I am using:
v.db.select map=PHL_adm1 where=NAME_1='Bulacan'
My vector map is over the raster map. I want to select the part of the raster map under the polygon(NAME_1='Bulacan') of a vector. Is it ...
1
vote
1answer
1k views
How to combine a vector and a raster file?
I want to combine a raster and a vector file. After combining, can I query on the resulting map to obtain a specific area? How?
0
votes
0answers
78 views
Display a single country with OpenLayers
Can I display a single country using Openlayers?
I'm not trying to restrict zoom levels or . I want only one single country to be displayed. The rest of the world cannot be displayed.
My reasearch ...
0
votes
1answer
685 views
openlayers- WFS- Cross-domain problem
I got the typical cross-domain problem when access to WFS layer by using openlayers,
XMLHttpRequest cannot load http://XXXX/geoserver/ows?service=WFS. Origin http://XXXX is not allowed by ...
