lagerratrobe
  • Member for 10 years, 6 months
  • Last seen more than 1 year ago
  • Seattle
Best GIS system for high performance web application - PostGIS vs MongoDB
21 votes

I've been using PostGIS for a few years and only recently started to investigate how I could use MongoDB to deal with certain use-cases. I was dealing with point data that had sparse fields - like ...

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When should you NOT use a spatial index?
11 votes

I think this is implied, but I would NOT use a spatial index for a query when I had a non-spatial index that I could use instead. For example, I have 2,113,450 points that span the United States ...

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How to store lines and polygons in JSON documents?
9 votes

This is simply not true, "to take advantage of spatial indexes in Mongo, you'd need a spatially indexed collection holding nothing but a record for each of the polygon's points, with an additional ...

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Migrating data from ArcSDE to PostGIS?
6 votes

PostGIS has a loader named shp2pgsql that you can use to load shapefiles into a PostGIS database. One of its options ( "-d" ) drops the existing database table before loading the data. It should be ...

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Convert Lambert Conformal Conic to WGS84
5 votes

I like MerseyViking's answer but would suggest a slightly different workflow, still using FWTools though. Define the LCC projection: if nonstandard, define projection by adding definition in epsg ...

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Why does GRASS eliminate polygons when using v.generalize?
Accepted answer
4 votes

Answer from GRASS development team. "The disappearance of polygons [in v 6.4.1] happened because smoothed boundaries that violated vector topology were deleted, after that all boundaries that were ...

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Google earth Borders on Google maps
Accepted answer
3 votes

No, it is not possible for you to access the underlying geometry that is used to represent these borders in Google Earth. Nor is it possible to use them separately in Google Maps as KML. Your best ...

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Mapserver + NDVI styling
2 votes

I'm a little confused whether your wish for grayscale output is for display purposes, or for output format type (8-bit output). In any case, if the desire is solely for display, then obviously you ...

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Python, shapely library: is it possible to do an affine operation on shape polygon?
2 votes

Grass can do it using v.transform.

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How can I create an adapter between the ArcGIS REST interface and WMS or TMS?
Accepted answer
2 votes

Yes, it should be possible to do this using the GDAL_WMS driver from GDAL. There is even an example at that page that points to another ArcGIS REST instance. However, I have not been able to make ...

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Cropping an image with a map extent
Accepted answer
2 votes

Clipping an image to the extents of a bounding box is very easy to do with the gdal_translate utility from GDAL. The documentation for it is here. You'd want to use the "-projwin" option like this, ...

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Can I split up v.in.ogr into multiple v.clean commands?
Accepted answer
1 votes

Answer: The following steps are what v.in.ogr does to clean polygons that are loaded with the "-c" flag: v.clean tool=snap type=boundary thresh= 0.000001 v.clean tool= bpol type=boundary v.clean ...

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v.dissolve (and other scripts) not in GRASS path
Accepted answer
1 votes

Glad to hear this will be resolved soon, Markus. I found traffic from 2009 where you and I had discussed this problem then. I'd just stopped using GRASS since then and forgotten the solution. Just ...

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How to filter OSM files based on tags using Osmosis?
0 votes

This won't help you with reading OSM files locally, but you might try your query through the new MapQuest XAPI - http://developer.mapquest.com/web/products/open/xapi. I suspect it might give you back ...

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