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1500 questions
37
votes
7 answers
Nearest neighbor between point layer and line layer?
I've asked this question several times on stackoverflow and irc between #qgis and #postgis and I also tried to code it or implement it my self in postgis with no real answer.
Using programming (most preferably python), I'd like to draw a line from…
dassouki
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37
votes
3 answers
What is the proper syntax and usage for ArcGIS "in_memory" workspace?
I am unclear how best to use the in_memory workspace in ArcGIS. The best resource I have found on the subject is from ESRI on Using in-memory workspace. Unfortunately, the help section is not very informative. Also, there is a post on this site…
Aaron
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37
votes
4 answers
Fully load raster into a numpy array?
I have been trying to check my filters on DEM raster for pattern recognition and it is always resulting in missing last rows and columns(like..20).
I have tried with PIL library, image load. Then with numpy. The output is the same.
I thought,…
najuste
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37
votes
6 answers
Difference between map layer and spatial dataset (e.g. feature class, shapefile)?
What is the difference between a feature class and a feature layer?
To me they seem very similar in concept.
user
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37
votes
4 answers
What was the rationale for the non-standard UTM zones near Norway?
UTM zones 30V, 31V, 32V, 31X, 33X, 35X, and 37X do not line up with the rest of the UTM zone grid.
Why was this allowed? According to Wikipedia, UTM was developed by the U.S. Army Corps of Engineers in the 1940s. What prompted them to have special…
Jaime Soto
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37
votes
2 answers
Choosing coordinate system to store geography data for celestial coordinates
I am doing an astronomy project. I want to have the information about our images stored in a spatially enabled database. This, I would think, should be a very easy special case for GIS functions because the sky can be treated as perfectly spherical,…
SO Stinks
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37
votes
5 answers
Adding Layer Files (.lyr, .lyrx) to QGIS
At college we use ArcGIS Desktop 10, but that does not function on my Mac so I have QGIS there instead.
I want to do my exercises with QGIS, but in ArcGIS Desktop we use .lyr files with ArcMap and .lyrx files with ArcGIS Pro, and they are not…
David
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37
votes
5 answers
Why does PostGIS installation not create a template_postgis?
I went this route for installation of PostgreSQL and PostGIS:
PostgreSQL using the standalone KyngChaos,
PostGIS install from KyngChaos as well...
pgAdmin3 from PostgreSQL Tools
Now when I launch pgAdmin and try to create a new PostGIS database,…
Michael Markieta
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37
votes
4 answers
Why is GPS a free service?
The Global Positioning System (GPS) is a free service that is owned and operated by the U.S. Government and is always available.
When we buy a GPS device, we don't pay a monthly fee or pay a tax for GPS support. We only pay the price of the…
Arturo Herrero
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37
votes
8 answers
How do I convert State Plane coordinates to latitude-longitude?
Given a specific state plane coordinate system (whether NAD27 or NAD83), are there any resources to convert to latitude-longitude?
Richard Morgan
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37
votes
7 answers
Fixing geometry validity errors in QGIS 2
I am working on ownership data at a US county level. I have one shapefile per county that contains thousands of tax parcels. I need to dissolve the polygons representing parcels owned by the same individual.
When the shapefile is not clean, the…
Bap
- 983
- 3
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36
votes
3 answers
Best GIS system for high performance web application - PostGIS vs MongoDB
I am working on a web/mobile application based on location data. Since i am already familiar with MongoDB, i found the geospatial indexing of mongo is quite suitable for my needs. As i am mainly dealing with simple/short location points, Mongo 2d…
RameshVel
- 515
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36
votes
6 answers
Finding if two polygons intersect in Python
I'm looking for an algorithm, a high-level solution, or even a library which can help me determine if two polygons intersect, in Python.
I have the vertices of the two polygons (These are single-part polygons without any holes) in two different…
Devdatta Tengshe
- 41,311
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36
votes
5 answers
Advantages of using spatialite over shapefile?
I found spatialite more useful than shapefiles as it does not have the limitations of shapefile and it is also portable. Many people here use shapefiles to exchange data and even the experts do not know about this new format.
What are the advantages…
neogeomat
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36
votes
3 answers
Is there a Carto CSS Gallery which also contains code?
I am currently exploring the usage of CartoCSS and TileMill in one of our projects. I have seen the impressive gallery available at http://www.mapbox.com/tilemill/gallery/
The gallery looks impressive, but I am having trouble imaging how they…
Devdatta Tengshe
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