Questions tagged [vector]

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

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votes
0answers
815 views

Creating a sidewalk map for a walkability survey

If I wanted to do my own walkability survey of my city, what tools could I use? I have map data from OpenStreetMap, but I have to consider that streets have two sides (which aren't always accessible ...
4
votes
2answers
1k views

Stylized map workflow: Illustrator to Google Maps / OpenLayers

The aim My current aim is to create a series of (heavily) stylized diagrams and maps. I'm not very familiar with any GIS software, so my weapon of choice would be to use illustrator for creating the ...
3
votes
1answer
2k views

Openlayers Add features performance for 3000 lines

We would like to implement the function of Addfeature in openlayers to draw lines and push them onto a vector layer, and overlay this layer onto open street map or google map. Those lines are draw ...
1
vote
1answer
224 views

Any freely available vector data in cylindrical projection?

I'm trying to develop an application in PHP to plot various points in Europe from a database, and serve them dynamically on a map. I think this should be relatively straightforward when using a map ...
2
votes
1answer
1k views

How to clean vector segment intersect errors in GRASS

I'm using GRASS to process a vector map. When I export back to .SHP and do a 'Check Geometry Validity' in Quantum GIS it lists several errors of this type... 3,segments 199 and 203 of line 0 ...
1
vote
1answer
283 views

Why is the geonames not loading?

I want to import a geonames file. I downloaded the geonames .txt file from http://download.geonames.org/export/dump/ I used: v.in.geonames input=PH.txt output=ph but it displayed ...
3
votes
2answers
152 views

Obtaining OS MasterMap time series data

I am trying to do a research project on changes in Land Cover in a London borough over time. I have access to OS MasterMap data through Digimap (the service that provides this data to universities in ...
7
votes
1answer
623 views

How to use simplify()

i have my Vector Data saved in a PostgreSQL PostGIS enabled Database. The Data im displaying is very detailed, i want to simplify it through the simplify() method of Postgis. I duplicated one of my ...
4
votes
1answer
1k views

How to extract features from a vector layer?

I have a vector file containing the river lines of an area. I want to extract a specific water line from the vector. I used: v.db.select but it only displayed: cat|F_CODE_DES|HYC_DESCRI|NAM|ISO|...
12
votes
1answer
540 views

Spatial operators in R?

How can I do spatial selections or filters in R? I can do this in PostGIS using (e.g.): SELECT * FROM mypoint, mypoly WHERE ST_Within(mypoint.geom, mypoly.geom); and it is similarly a piece of cake ...
5
votes
2answers
954 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 ...
1
vote
1answer
1k 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
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1answer
5k 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?
2
votes
2answers
641 views

How to query data from a vector map (shapefile)?

We want to obtain the specific place of the boundaries of a shapefile. We want to be able to get the points of each polygon corresponding to a specific place in order to use these data in an algorithm....
7
votes
1answer
2k views

Programmable buffers using GDAL and python

Is there a way to programmatically generate buffer layers for vector layers using GDAL and python?
5
votes
3answers
5k 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?
1
vote
1answer
139 views

How to reference vector based data to raster data that already has spatial reference in MAPublisher?

I have been able to load in raster data into MAPublisher and properly registered it, however I have been having trouble with a further step. I am trying to reference vector data that has no GCS or ...