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1500 questions
36
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3 answers

Handling multiple map frames with different layers in one print layout?

Often I need two (or more) map frames in map layout to present different data next to each other. It is easy to make multiple map frames in QGIS Print Composer. BUT... It is in the nature of my work that very often I need to update some map frames…
Miro
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36
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8 answers

Download Dataset From ArcGIS REST Service

Looking at this information page for a dataset hosted on esri.com: http://fema-services2.esri.com/arcgis/rest/services/2012_Sandy/ImageCat_NLT/MapServer/layers Trying to figure out how I can get access to the raw data (either raw lat/lng coordinates…
Steve Horn
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36
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7 answers

Changing CSV layer attribute value from text to number in QGIS?

I read in a CSV file for linking to a .shp file. All the variables that are just numbers came in as text. How do I change the text variables to numeric in QGIS?
HealthMaps
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36
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2 answers

Changing geometry type from Point to Multipoint within existing table in PostGIS?

Is there a PostGIS function that can change geometry type for an existing table? We need to change from POINT to MULTIPOINT. The table will be empty when we change the geometry type and we cannot just drop/create the table.
Ulrik Balslev
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36
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2 answers

Point in Polygon analysis of 200 million points

I have a CSV containing 200 million observations with the following…
meer
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36
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9 answers

Is there a good GPS track analysis library?

I keep writing custom code to work with GPS tracks: GPX files and NMEA logs from my phone, dedicated GPS logger, etc. I feel like I'm reinventing the wheel and am wondering if there's some standard library / tool I can use to work with GPS tracks.…
Nelson
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36
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11 answers

Seeking alternatives to pgRouting for open source routing / network analysis?

I was wondering if there are any alternatives to pgRouting tools. Thinking about it for a bit, I think the only alternative is to use R or RPY to do the analysis. Basically I'm trying to solve routing problems based on nonPostGIS databases. As most…
dassouki
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36
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4 answers

GIS professionals working from home

How many of you out there work from home? What kind of company / organization do you work for (private, government, municipal, institution..)? How did you convince your employer it was a good idea? What are the major drawbacks to working in a GIS…
Matt
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36
votes
5 answers

Is there a way to render lines with a smooth (bezier) curves in QGIS?

I am moving from creating maps with Illustrator to making them with QGIS and actual data. One of the things I haven't been able to re-create in QGIS are the smooth curved lines I can get in Illustrator. I am not talking about Join and Cap Styles,…
Lost Mapper
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36
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12 answers

What is the state of the art in html5 geospatial applications?

I am very interested in the HTML5 canvas element for maps; work like Cartagen from an MIT Media Lab researcher looks very promising, for example. There is some interesting SVG based work at carto.net. WebSocket seems like a fantastic API for live…
bvmou
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36
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5 answers

Identifying clusters in vector point data using QGIS?

I have a vector dataset of rural broadband data-points (how fast, etc.) and I'd like to explore if there are clusters of points with similar characteristics, and to plot polygons encompassing them. For example, I may have 45,000 points in a single…
Adrian
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35
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37 answers

Great GIS, maps & cartography quotes

Programmers' list has been a pleasure to read. Stats' list is growing fast as well. So perhaps there is a place for separate one on this site? Please share your nuggets of wisdom / humour / inspiration from the world of GIS, cartography and mapping.
radek
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35
votes
2 answers

LAS to DEM conversion

I regularly come across LiDAR (.LAS) files with elevation data. When I do, I always struggle to find a way of converting them to a DEM for hydrological analysis. I have developed several workflows, and even if they usually (but not always!) output…
Martin
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35
votes
2 answers

What is the unit used in ST_Distance()?

I wonder what the unit is of the float being returned from ST_Distance. In the documentation it says: ...cartesian minimum distance (based on spatial ref) between two geometries in projected units. What are these projected units? The geometry is…
stUrb
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35
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0 answers

How to use PostgreSQL/PostGIS with ArcGIS for Desktop?

Has anyone used PostgreSQL with PostGIS successfully? I am a semi-experienced ArcGIS user and want to build out a database and connect it to ArcCatalog. I've scoured the internet for resources but nobody has really given a good walkthrough.
dgrubman
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