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1500 questions
20
votes
1 answer
How to export only one band from an image using GDAL?
I have a multi-band GeoTiff, and I want to extract only the first band and write a new image consisting of only that band.
How do I do this using GDAL?
Devdatta Tengshe
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- 35
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20
votes
5 answers
Source for high-resolution satellite images free/low-cost?
I am doing a household survey in Kenya, and I need to ensure that my survey team visits every house within a given area. I've been going to google maps and right-clicking on roofs to get coordinates via the "what's here" option. This is really an…
generic_user
- 403
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- 11
20
votes
1 answer
PostGIS select by lat/long bounding box
I have a minLat, minLong, maxLat and maxLong from a box drawn on a map. Right now, my query to get all the points in the box looks like this:
SELECT *
FROM geomTable
WHERE (longitude BETWEEN minLon AND maxLon)
AND (latitude BETWEEN minLat AND…
bl8rchk
- 551
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- 14
20
votes
7 answers
Changing order of features in shapefile
I have a shapefile and I want to change the order of the features.
Is that possible?
I want to sort the features in the shapefile because I'm embedding this shapefile in a mobile app. The app will display a list of features, and although I could do…
tato
- 823
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- 7
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20
votes
8 answers
Where to start learning how to make maps with QGIS?
I have no skills in GIS, "map-making," or any other map program. Been a county planner for 25 yrs, where there was always a "drafting" staff. I'm in another agency now and need to be able to produce basic and attractive site plans and area maps. …
Des J
- 201
- 2
- 3
20
votes
7 answers
Code-completing/auto-completing ArcPy scripts using Notepad++ (external editor)?
I have been scripting in Python for ArcGIS 10, and so far I have just been using Notepad++.
I like how the Python command line interface code-completes arcpy functionality for you, showing you your options, and I was wondering if there is a way to…
Tanner
- 7,375
- 14
- 62
- 109
20
votes
3 answers
Casting ArcPy result object from arcpy.GetCount_management() as integer instead?
I am using ArcMap 10.1.
I am trying to get a number by counting how many points are in a shapefile. And this works, except I then am running into trouble using that number somewhere else. Eventually, I'll be using that count in some math (field…
Erica
- 8,974
- 4
- 34
- 79
20
votes
3 answers
Algorithm to find nearest point
I have a list of a few hundred cities with their latitude/longitude. Given another location (also in lat/long) I need to find the nearest city.
As I don't use any GIS, by now the obvious algorithm is to make a loop for all the cities, calculating…
lujop
- 365
- 1
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- 7
20
votes
5 answers
Good resources on geocoding algorithms
Do you know of any good resources on geocoding algorithms?
I am particularly interested in address query parsing, including matching and weighting parts of the query, dealing with misspellings and variations, as well as in details about the physical…
Petr Krebs
- 10,291
- 1
- 22
- 33
20
votes
3 answers
Learning to use expressions in QGIS?
Is there any resource recommendations in general for getting past the basics of QGIS and going into the deep dark secrets?
Specifically in relation to expression coding for labeling, queries, etc.
LandArch
- 2,201
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- 26
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20
votes
4 answers
gdal ImportError in python on Windows
Trying to import gdal for Python 2.7.3 on Windows XP:
>>> import gdal
Traceback (most recent call last):
File "", line 1, in
File "C:\Python27\lib\site-packages\gdal.py", line 2, in
from osgeo.gdal import…
meetar
- 431
- 1
- 3
- 13
20
votes
11 answers
Would you consider online geocoding a breach of privacy?
Suppose I have a bunch of addresses of individuals participating in a certain study (most likely - health related, where privacy and ethical considerations are always important issues).
Nowadays, providers like Google or Yahoo offer decent results…
radek
- 10,579
- 12
- 86
- 121
20
votes
8 answers
How to manually break statement execution in Python window of ArcMap?
How does one break the execution of a long-running process in the python console of ArcMap?
For example, how do you break a long iteration like the one below once it is started?
for i in range(1, 50):
# some long process which takes over a minute…
Alex Essilfie
- 369
- 2
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- 13
20
votes
1 answer
Is there an comparison of the various mapping libraries for Android?
I am currently looking at the various libraries that I can use to show a map in my custom Android App. I have found several like Mapsforge, OSMDroid, ArcGIS runtime for Android, Google Maps for Android and so on. I'm sure that I am missing a few.…
Devdatta Tengshe
- 41,311
- 35
- 139
- 263
20
votes
1 answer
What is a "non-noded intersection"?
Can someone provide a precise definition of what a "non-noded intersection" is? There are various GIS platforms and toolkits that have errors with this text, and Google search results for this tend to fall in the category of "drop some precision and…
FMM
- 309
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- 4