GIS Stack Exchange
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1500 questions
21
votes
3 answers

Replacing all null values from attribute table with zeros in QGIS

In QGIS 1.8 I have a new column in my attribute table with a lot of NULL values and I want to replace all them to zeros. How can I do that in field calculator?
Maria
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21
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6 answers

Calculate bounding box coordinates of a selected polygon with QGIS

I just manually (and somewhat inaccurately I'm sure) retrieved the bounding box coordinates for a county polygon, which is a selection from a larger layer of county shapes. I'd like to be able to use a QGIS plugin or other function to calculate this…
boulder_ruby
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21
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4 answers

Is there a tool that performs automatic recognition of buildings?

I'm wondering if there is a tool, which takes a satellite map of a region, detects typical buildings and allows the user to review its result (check, whether the tool correctly identified the buildings). By "typical buildings" I mean the…
Glory to Russia
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21
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3 answers

Saving vector layer with specific symbology using QGIS?

I am creating a polygon feature layer with soil classes in QGIS. I need to share this layer with some colleagues and I need the layer to maintain the color ramp I have created. Is there any specific format where the color ramp is saved together…
Graellsia
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21
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2 answers

Understanding terms in Length of Degree formula?

Online calculators such as http://www.csgnetwork.com/degreelenllavcalc.html (view page source) use the below formulas to get meters per degree. I understand in general how distance per degree varies depending on latitude location, but I do not…
Brent
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21
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4 answers

Why latitude/longitude and not other way round?

When you google "latitude/longitude" you get 10 times more results than "longitude/latitude". This I find very confusing as "x/y" seems 20 times more common than "y/x". But on a map Latitude is on the Y axis and longitude on the X. Any…
Moak
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21
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10 answers

Freelancers, how do you handle deliveries to remote clients?

Freelancers and small business owners, how do you handle product delivery and support to your remote clients? Example: I have a client who knows enough about ArcMap to add a shapefile, turn layers on and off, print a map, etc. - GIS isn't their…
Chad Cooper
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21
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5 answers

What is projection of WGS84 in GIS software?

WGS84 is a reference ellipsoid that determines coordinates of every point on Earth using latitude, longitude and height about the its surface. This ellipsoid is often used as a base to make maps. Though, to make a map on a flat paper or a flat…
multigoodverse
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21
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1 answer

What is topojson and how is it different than geojson?

This is a conceptual question. What are the differences between these? and what are the pros and cons of these formats?
neogeomat
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21
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2 answers

Converting projected geoTiff to WGS84 with GDAL and Python

I am VERY new to this whole GIS thing. I am trying to convert some projected geoTiff images to WGS84 using gdal in python. I have found a post that outlines the process to transform points within projected GeoTiffs using something similar to the…
JT.WK
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21
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8 answers

What are useful websites for scouting GIS related jobs?

What are useful websites for scouting GIS related jobs?
radek
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21
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7 answers

Removing only some donut holes from polygons using ArcMap

I am using ArcMap 10.0. I have a trick for removing the donut holes, which is converting the polygon to line and then creating polygon out of the lines and in the end merging all of them. The drawback of this strategy is that in removes other holes…
Arash
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21
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4 answers

Converting x,y coordinates to longitude,latitude using QGIS

I'm working with this downloadable shapefile that has X Y coordinates. They are akin to '3672187.92698000, 534175.72095400'. I would like to convert them to longitude latitude so they are more like '-90.097017, 29.963176'. I've seen this question…
Aaron Silverman
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21
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2 answers

Using ArcPy to determine ArcMap document version

Is there a way with ArcPy to identify the version of a Map Document (MXD). I am working on a solution to inventory our MXD's and would like to know if a document is 8.1, 9.2, 10.0, etc. I am currently using ArcMap 10.0, but if there is an update in…
RyanKDalton
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21
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4 answers

Opening and extracting data from Shapefiles?

We are in need of US highway data. We found it for Florida at the state GIS website. We downloaded the data for Florida highway intersections from here (this is a zip file). How do we use these files and extract the geocode values of the…
dotcoder
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