Questions tagged [gis]

For questions related to Geographic Information Systems: any digital tool that is designed to obtain, edit, analyze, and present spatially organized data. However, please note, a dedicated site for GIS questions, gis.stackexchange.com, might be a better place to ask GIS-related questions.

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1 answer
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Software for spatial interpolation of temperature and relative humidity data from weather stations

I'm working with time series of weather data (specifically, min/max daily temperatures and relative humidity) recorded from weather stations over an area of about 200,000 km2. I would be interested in ...
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7 votes
2 answers
161 views

How can smartphones help geologists in the field?

Smartphones have incorporated many sensors and some of them can be helpful for a geologist in the field: They have GPS, so it is possible to register your route in a Google Maps map. I find this may ...
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4 votes
1 answer
115 views

Rainfall Anomaly Index using satellite data

I'm working on a script for calculating the Rainfall Anomaly Index1 (RAI) for an area using satellite imagery to estimate precipitation. The context I have seen the RAI used in before is for weather ...
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2 votes
1 answer
40 views

When calculating a precipitation index, should it be constrained to a basin?

I am writing a script for calculating a precipitation index using satellite imagery, and am wondering if it can be applied to an arbitrary area or if it should be constrained to a basin. My gut says ...
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  • 65
1 vote
0 answers
27 views

Literature on thematic 4D maps

I need to understand more about thematic 4D mapping. I would roughly classify it as a method of cartography. In particular I want to do research on what software is being used to create thematic 4D ...
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1 vote
3 answers
175 views

convert .srtm to xyz ord grd

I need to plot bathymetry map of my study region and need to convert the .srtm to .xyz or .grd format to use GMT. I tried to do this with grdraster and xyz2grd, but got wrong results. I found that ...
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1 vote
1 answer
74 views

High-resolution georeferenced population data [closed]

Can anyone recommend a good source for high-resolution georeferenced population data? I know that Natural Earth Data's Cultural Vectors e.g. contain the population per country. However, I am looking ...
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  • 183
1 vote
2 answers
175 views

download NASA Earth Exchange Global Daily Downscaled Projections for single lat lon

I have a lat lon - 23.14, 83.14 and I need to download the NASA Earth Exchange Global Daily Downscaled Projections (NEX-GDDP) data from the below website only for this lat lon. https://dataserver....
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  • 169
2 votes
1 answer
242 views

Code for DEM based flow routing in R

I have a DEM as shown for which I have determined flow paths using D8 algorithm (My own code) in R. The resulting DEM with the flow paths is also shown. The flow paths are generated in the form of ...
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3 votes
1 answer
219 views

Great circle in UTM coordinates

I've got a question about calculation of great circles in Cartesian coordinates: Is it possible to compute points along a great circle in UTM coordinates, i.e. given two points P1(easting1, northing1)...
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  • 31
6 votes
1 answer
373 views

Which mountains (or hills) are visible from both Boston and Rhode Island?

In the description of the Norse exploration of America, there are two places mentioned, "Hop" and "Straumfjord", with some relationship to the same mountains. E.g. The finding of Wineland the Good, p....
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  • 163
1 vote
1 answer
465 views

How to extract lat-lon from MOD10C2 hdf data in matlab?

We can import and read all given bands/parameters of MOD10C2, lat and lon is not given as separate band rather embedded with other bands. How we can extract from MOD10C2 hdf data in matlab. Similar ...
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  • 109
1 vote
1 answer
107 views

How to figure the MODIS snow cover against different elevation zones?

I am working on MOD10C2 (8days snow cover), when I clip the MODIS snow cover against different zones of elevation the results was against general trend .i.e. the higher elevation was showing lower ...
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  • 109
6 votes
1 answer
221 views

Would more or less land be usable if global temperatures rose?

I think a large portion of the earth's land is unusable from being too cold and land that is too hot does not have enough water and dries out which could be fixed by diverging water to those areas. ...
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2 votes
2 answers
314 views

where to download NASA-NEX daily downscaled datasets?

I'm looking to download a small geographic area of the CMIP5 models part of NASA-NEX dataset. Previously I relied on the Planet OS OpenNEX GDDP website which had a great tool for selecting geographic ...
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4 votes
1 answer
94 views

how to know the correct results in watershed delineation in ArcGIS?

When I use one DEM in my study area to delineate watersheds, the results are different from when I mosaic 4 DEM layers adjacent to each other. After the mosaic process, 3 of the basins were merged in ...
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2 votes
1 answer
423 views

Looking for global cloud cover animations or videos

I am looking for a video of global cloud cover. Something like an animated version of this image: (Originally presented at http://naturalearth.springercarto.com/ne3_data/8192/clouds/africa_clouds_8k....
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5 votes
2 answers
12k views

What is the distance between the tropics?

What is the distance between the tropic of cancer and the tropic of capricorn here on Earth? Now this would seem like I could simply google the answer to it and know the exact distance in miles (...
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  • 153
3 votes
0 answers
92 views

Approaches for estimating potential evapotranspiration for non agricultural landuse classes

We are studying the water balance of a small catchment close to Jaipur, Rajasthan India in a semiarid climate. About a quarter of the landuse within the catchment is agriculture, the rest is divided ...
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  • 183
8 votes
1 answer
825 views

Confusion with precipitation values in CORDEX MPI-ESM rcp data

I want to analyze climate projection data for the different RCPs for a region in north western India, which has an arid climate. I chose MPI-ESM data downscaled with CORDEX. An example filename looks ...
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  • 183
4 votes
1 answer
65 views

Is there a measure for the "dominance" of a city's population?

since there are topological isolation as well as prominence as measures to describe how "dominant" a summit is in comparison to the ones surrounding it, I was thinking about a similar measure to ...
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3 votes
1 answer
336 views

To delineate the drainage basin for a lake, would the pour point be the inlet or the outlet?

I am interested in the area draining into and affecting a particular lake. Delineating this drainage basin, should I use the lake's inlet or outlet to best capture the relevant drainage basin? I think ...
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  • 1,178
1 vote
0 answers
22 views

Categories for supervised classification, wildlife analysis

I am using GIS to undertake a small research on the loss of natural habitat in north England. I will be using Supervised Classification where I train the system on a few examples, e.g. shallow water ...
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1 vote
0 answers
26 views

Has there been loss of natural habitat in north England?

Has there been loss of natural habitat in north England or Britain in general over the past years? If there was, what is the loss in percentage? A reference would be highly appreciated
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2 votes
0 answers
286 views

How to determine associated USGS stream gauges with a watershed HUC?

USGS stream gauges have an associated drainage area, but the associated hydrologic unit listed by USGS is often different than the actual drainage area. How can one determine what hydrologic unit ...
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  • 1,178
2 votes
1 answer
248 views

What divides Hydrological Unit Code areas of the same level?

I'm trying to better understand the Hydrological Unit Code (HUC) system of the United States. I understand the basic hierarchy of it (HUC4, 6, 8, 12) and watersheds/drainage areas. Here's what I want ...
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  • 1,178
7 votes
1 answer
173 views

Why do forecast areas on weather.gov appear as twisted squares?

I get my weather forecasts from good ol' NOAA's weather.gov site. On the detailed site weather pages, there's a map that shows the forecast area as a green square (for Boston at least, the square is ...
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