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1500 questions
44
votes
5 answers

How to determine if a tiff is georeferenced or not?

I received a tiff file from someone, but I'm not sure if it's georeferenced. Is there an easy way to check this?
Jeff Storey
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44
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8 answers

Export Google Maps Route to KML/GPX

Since Google pulled the plug on Google Maps Classic, I'm reluctantly moving to its Google Maps New application. However, I didn't find how to export a route to a GPX or KML file so it can be copied onto my smartphone. Can it do this? If not, is…
Gulbahar
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44
votes
3 answers

Displaying only selected features on map in QGIS

Not sure if this option ever existed, but the new QGIS version hides a lot of things somewhere else and this seems so simple that I'm kind of convinced it was possible to do this before. I have quite a large data set with ship tracks. I now want to…
Kristina
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44
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9 answers

Open source methods for kriging?

I have a point dataset which I'd like to Krige, ideally using an open-source software package. If possible, I'd also like to choose the semi-variogram model during the process to improve the estimation.
scw
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43
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7 answers

Choosing File Geodatabase (*.gdb), Personal Geodatabase (*.mdb) or shapefile format?

Previously, I have used geodatabases as an easy way to keep all files together rather than having dozens of shapefiles all over the place, and it is easier when finally exporting all the relevant data to the client. Why should I use a geodatabase…
Martin
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43
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5 answers

Curved point-to-point "route maps"

I have recently been looking at airlines web pages that display their routes departing a certain city to all other cities they service. I would like to be able to create similar curved routes between points. Has anyone created scripts or functions…
RyanKDalton
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43
votes
3 answers

Seeking tutorials, books, papers, blogs, etc to handle spatial data in R

Does anyone know some good tutorials, books, papers, blogs, etc to handle spatial data in R? I know that there are some packages like rgdal and maptools but I haven't actually found useful tutorials to get in touch with the basic functions (read,…
Dspanes
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43
votes
4 answers

Convert GeoJSON to TopoJSON

How can GeoJSON data to TopoJSON be converted? TopoJSON files are often smaller than GeoJSON and the conversion allows you to incrementally simplify a dataset, if you wish.
Jeff
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43
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5 answers

Reprojecting raster from 0 360 to -180 180 with cutting 180 meridian using gdalwarp

I have a geotiff raster image that has a coordinate system with longitudes from 0 to 360. The horizontal center of the image is 180 longitude. See image below: I want to transform it to EPSG:4326 SRS with -180 180 longtitude range. And I want the…
nextstopsun
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43
votes
2 answers

Projecting sp objects in R

I have a number of shapefiles in different CRSs (mostly WGS84 lat/lon) that I'd like to transform into a common projection (likely Albers Equal Area Conic, but I may ask for help on choosing in another question once my problem gets…
Ari B. Friedman
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43
votes
7 answers

Creating new layer from selection in QGIS

Is it possible to create layers from selection in QGIS? I am using QGIS 1.7.4-Wroclaw. To make it easier for others to see this, here are some pics. I used QGIS 2.0.1-Dufour. Selecting Saving Adding
Stat-R
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43
votes
9 answers

Generating random locations nearby?

I am trying to create random locations nearby my location. What i want is to create random latitude/longitude pairs inside a 200 meters circle surrounding my location. This is the formula i came up with (with the help of people at…
pindleskin
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43
votes
1 answer

Finding center of geometry of object?

Given a set of 2D or 3D points: How to find the center of geometry of an object? According to the following figure, the center of geometry differs from the center of mass if it is calculated in the simplest form i.e., homogenous density of mass. The…
Developer
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1 answer

How to convert/typecast from Polygon to Multipolygon in PostGIS?

Is there any way to typecast Polygons to Multipolygon type? For example, I have created a circle using ST_Buffer() on a point. The return type of that function is of Polygon type. The problem is that on the geometry column there is a restriction…
Vicky
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42
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12 answers

Representing network flows?

For a project I'm working on, I need to represent network flows over 1,000 zones with directionality. Any suggestions on displaying the information in a nice and non overwhelming way? Any examples on displaying network flows in heavy urban…
dassouki
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