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1500 questions
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3 answers

Leaflet: how to draw curved lines?

So, I'm trying to draw curved lines in my application which is based on a Leaflet map. As far as I know Leaflet does not support drawing curved lines at the moment, so my question is really more about how to best get some curved line funtionality in…
fgysin
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Python equivalent of gdalbuildvrt

Is there a way to perform the same task as the gdalbuildvrt utility using GDAL Python bindings? So far I have not found any way to do this other than creating a vrt of a single dataset and manually editing the xml. I would like to create a vrt…
Brian
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18
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1 answer

How to create an attractive choropleth map in R?

I've been experimenting with choropleth mapping techniques in R, having reaped the benefits of ggplot2 for creating beautiful graphs within a powerful data analysis package. When it comes to mapping I've failed to produce results comparable to…
RobinLovelace
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18
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3 answers

How to speed up queries for raster databases?

I have a raster database in postgresql/postgis with these columns: (ID, rast, data_of_data). 'rast' is the column that has raster files in WKT format. An example query to find the DN value of a point in WGS84 system (30.424, -1.66) and for…
f.ashouri
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18
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3 answers

Getting tabular statistics from table using QGIS?

Are there QGIS tools that will allow users to get tabular statistics from their table? I kind of expected I would be able to just open the table, select the field I was interested in, right-click on the field header and get something similar to…
RyanKDalton
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18
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3 answers

Alternatives to Manifold GIS?

Question from my father who is looking to explore alternatives to Manifold: "I am an independent environment consultant who is a heavy user of GIS for spatial data crunching, geo-referencing self-digitised maps, terrain modelling using LIDAR and…
RobinLovelace
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18
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4 answers

How to style points in QGIS based on multiple attributes

While trying to find a useful way having earthquakes displayed, I noticed that it isn't that easy to manage. I'd like to be able to recognize the "Magnitude", "Date", and "Depth" from the style of the point. Something like: size: based on…
Chris Pallasch
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18
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3 answers

Deleting multiple features easily in QGIS

I have a vector layer being rendered in QGIS. I want to delete various features in the layer. I'm currently deleting each node by selecting the node through node tool and then pressing the delete button. But I want to delete very large portions in…
Sibi
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18
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1 answer

Are there torrents that contain large free spatial datasets?

I've been having a lot of issues downloading entire datasets of SRTM or ASTER GDEM2 or similar free datasets, mainly because of poor services. Does anyone know of any torrents which contain such free datasets?
U2ros
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18
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3 answers

How to improve cartographic visualization of overlapping polygons?

I need some advice about how to improve the visualization of cartographic information. User can select different species and the webmapping app shows its geographical distribution (polygonal degree cells), each specie with a range of color (e.g…
user1249791
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18
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2 answers

Creating GeoJSON that works with D3

I'm simply trying to convert a .shp file to a geoJSON format using: ogr2ogr -f geoJSON output.json input.shp After executing the command nothing seems to be wrong. Here's an excerpt from the output.json { "type": "FeatureCollection", …
Flavio
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18
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6 answers

What's the best way to produce a density map from weighted points in QGIS?

I'd really like to repeat the functionality of the ArcGIS Kernel Density tool - how could I do that? I would like to limit answers to easy-to-install free-and-open-source software – i.e. QGIS installs easily with GRASS on all platforms so…
Simbamangu
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18
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4 answers

Shaded relief from DEM in GRASS and QGIS

I have been trying to get a good looking shaded relief model out of GRASS and Qgis for a day or so now and just can't seem to get it. The biggest problem I'm having is the valleys look like mountains, but I just can't seem to get the right…
Nathan W
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18
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1 answer

Can we create views over a raster table in Postgis2.0?

Is it possible to create PostgreSQL views over a table that contains raster data? I have succeeded in creating the view but the entry in raster_columns is not correct (all the raster info is missing). Also, I couldn't open the SQL view using QGIS…
asp
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2 answers

In osm2pgsql how is the planet_osm_roads table populated?

I'm using osm2pgsql to populate a North America OSM database from planet.osm. I like how simple the resulting PostGIS schema is, but I'm a bit confused by its contents. I have the two tables planet_osm_roads and planet_osm_line. I assumed that…
tomfumb
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