华北多地灰霾堆积 冬天没冷空气华北灰霾正常
百度 在2013年，那时候我已在某汽车媒体从业了一年，早就知道9代车型要来了，虽然极度讨厌国产后的大板牙前脸，但那时候大肆宣传的EARTHDREAM地球梦发动机，让我对它的期待不减；虽然当时的媒体试驾会我没去，但那时的新车实拍和本地评测我都有参与，对它的了解也很深刻；它自然也成了我当年买婚车的首选，虽然后来有一些原因与它擦身而过，但也不影响我对它的爱!一转眼5年过去了，这5年里汽车行业发生了很多的变化，在9代车型进入了寿终正寝的时候，10代雅阁终于要来了，相比以往的雅阁，它变得太多，也让我对它的疑问也增添了不少；最大的变化是雅阁终于放弃了它用了几十年的自吸发动机，改用现在的SPORTTURBO（锐·T动）发动机。
Measuring data values at specific, discrete locations.
123 questions
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How to obtain a CSV file (feature collection) from a very large image in Google Earth Engine
I have a particularly large image (encompasses a large area at high resolution with 30 bands). I would like to have a CSV file with one pixel per 10km grid cell, and another CSV file with one pixel ...
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0
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44
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Cluster sampling of line data
I would like to create clusters of line data (geometry) for sampling, the geometry would be connected within each cluster. So far I’ve thought of:
Create a bounding polygon > split it into X ...
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1
vote
2
answers
78
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EarthEngine: how to sample pixels returning pixel geometry, not points
I would like to sample pixels within a given region, and extract the sampled pixel as a polygon. This will be used for ground-truthing at the polygon level.
I thought Image.sample would be the perfect ...
- 2,112
2
votes
1
answer
138
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Using Point Sampling Tool of QGIS
I am trying to sample raster values at locations in a points layer, using the Point Sampling Tool - a process that I have done successfully in the past. The process is failing with a Python error:
...
- 489
3
votes
2
answers
233
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How to auto-update field on geometryChanged() signal?
I have a point XY layer with a Z field used only for annotations. Sometimes there is a need to update the the geometry by moving the point manually. Since the layer is stored on an mssql server, the X ...
- 361
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1
answer
130
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Extracting values over a large area in Google Earth Engine: memory optimisation
I am trying to sample satellite (Sentinel-2 spectral metrics) data over a rather large area (1500 by 2500 km). I have around 2000 points relatively evenly distributed over this area.
However, even ...
- 61
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1
answer
273
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Smart Map plugin: error sampling 5000 data points
I'm trying to use the Smart-Map plugin in QGIS to do Kriging. I have about 15,300 data points and I need to sample the data (5,000 points, maximum for Smart-Map right now). But this error appears when ...
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3
votes
2
answers
2k
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Stratified random sampling in R
I want to generate 5 pairs of random points per each stratum. I have 4 strata that represent different rock types. For each rock type i want to generate 5 random points and to each random point I want ...
- 31
57
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5
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18k
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What are the benefits of hexagonal sampling polygons?
I am always on the lookout for useful methods to sample or partition study areas (usually in the form of raster datasets) into smaller units. Recently, I read an ESRI blog post about a new tool for ...
- 52k
0
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0
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69
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Spatial clustering vs sampling
I have a dataset with 100 millions Point (lat/lon).
I have started by using GeoHash clustering (applied dynamically by Elasticsearch regarding the user zoom level).
I end up with something like that:
...
- 11
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2
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1k
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Sampling points in R with both distance constraint and group
I have a spatial point data frame with categorical variable as a column named "type", I would like to draw a random sample from these points (let's say 100 points) with maximum and minimum ...
- 616
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1
answer
2k
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Selecting N samples uniformly from a grid points
I have a grid point shapefile. I want to select N number of samples from those set of grid points.
I tried pd.DataFrame.sample() but as we know it selects samples randomly. Is there any way I can ...
- 29
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1
answer
134
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Failed to print projection in GEE after sampleRegions
I'm using the function sampleRegions to extract the iamgecollection values from the sample plot I imported. I assigned the projection at first when doing the sampleRegions , however, when I want to ...
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1
answer
1k
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Random sampling In Google Earth Engine
I want to select random 90000 pixels/points from region of interest wherever there is built-up area. To my surprise when I print number of pixels selected it shows only 1044. I am literally lost how ...
1
vote
2
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145
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Randomly select non adjacent polygons in vector layer (QGIS) [closed]
I am trying to obtain a random selection of polygons (e.g., 100 polygons out of 400) with the condition that the selected polygons are not adjacent among each other.
Any suggestion on how to achieve ...
- 131