I need some help with postgis.
I have made a point geometry that have converted to text through st_astext.
I currently have these three columns:
object_id(uuid) komnr(int) st_astext_result(text)
2bcc1b26-0a7c-472a-9e74-9cadfefc2d44 320 POINT(687989.85 6135746.91)
I would like two columns each containing the east and north coordinate in the same syntax as it is now. Do you have any suggestions to how i may do this?
Preferred outcome would be:
east north
687989.85 6135746.91
Related
I have a data where at one latitude and longitude multiple shops are located.
For Example.
Latitude Longitude ShopId Type
6.24458 50.001756 101 Saloon
6.24458 50.001756 102 Groceory
6.24458 50.001756 103 Pharmacy
6.24458 50.001756 104 FishMarket
When on map I am plotting using above latitude & longitude I am getting single mark. And when I hover the mark I am getting single shop details but I want 4 marks and on each mark it should show respective shopid and Type.
I am new to Tableau and not able to figure out how to do it.
You are likely getting 4 marks displayed at the same location. So when you click on the mark you see, then you are only selecting the top mark. You can verify this by dragging over the mark to select all the marks within a selection rectangle. If you then, right click and view data, you should see all 4 marks.
Another thing that can help when you have overlapping marks, is to make the marks partially transparent and add a border around the marks. Both options are available by clicking on the Color button on the marks card to get to the advanced color settings.
If this is not the behavior you want, you have a couple of options. One easy approach is to add a little random noise to each latitude and longitude (called jitter). Adding a little jitter makes the marks visible, although the size of the jittering depends on your data and scale. Jittering is especially useful if all your points are geocoded to the same situation - say if every building with a Los Angeles address is treated as if it is located at city hall. In that case, the geocoding distorts the data to a degree that jittering is just fine.
The undocumented RANDOM() function is an easy way to add some jitter. Excel and Hyper Extracts support RANDOM() among other data source types. It returns a number between 0 and 1.
The other options involve treating your coordinates as continuous dimensions instead of measures, and then using some other visual attribute size, color etc to indicate the number of items at each location. It is often useful to combine nearby items with some sort of grid or hex bin function -- In this case, instead of adding random noise to each coordinate, you round or truncate it in someway to effectively snap points to a grid. The ROUND() and HEXBINX() HEXBINY() functions are useful here. When using this approach, be sure your packed coordinate fields are continuous dimensions and have the appropriate Latitude or Longitude geographic role.
Finally, take a look at the density mark type. It can make visual heat maps, either working with exact data points or grid packed points.
The Situation: I have a vector data map with all the countries in the World, including a unique landcode for every country. I need to convert it into a raster map, so I can eventually analyse (with Matlab) drought indicators for that country.
The Problem: The precipitation data I use has 720 columns and 360 rows. I want the raster map of world countries to be in the exact same amount of columns and rows. BUT the raster map also needs to have a cellsize of 0.5! Right now, when I use the vector to raster conversion tool, if I use cellsize = 0.5, the columns and rows become 720x287.
Question: How can I create a raster map of 720 columns and 360 rows, while setting cellsize at 0.5?
Thank you in advance!
Additional info:
Using ArcMap 10.4.1 and Matlab R2015b
Raster is .TIFF
Vector is .shp
As a fellow GIS user I would recommend posting your question under the GIS stack exchange, https://gis.stackexchange.com/
Beyond that there is some clarification needed. Are you saying that you are trying to create a multi band raster with 1 band for each column?
I solved the problem. In ArcMap, I imported the precipitation data (NetCDF). It was however flipped, but I could get it in the right orientation using the tools 'Flip' and 'Rotate'. Now this map had the right orientation and the right amount of columns and rows. Furthermore I just altered some of the default settings in environments: 1) I set the processing extent to the precipitation data. 2) I set the snap raster also to the precipitation data. 3) I set the cellsize of every output raster to 0.5. Finally, I converted the vector file of world countries to a ASCII file using the raster to ascii conversion tool. The ASCII file now has the same amount of rows and columns as the precipitation data!
I am already aware that this question, more specifically, should have been directed to GIS StackExchange. I already asked the question here but sadly, got no answers or any suggestions. I used ST_ClosestPoint() to project a point to the nearest line (point on line interpolation) using this approach.
Select ST_ClosestPoint(line, pt) As closest_pt_line
From
(Select ad.geom As pt,
st.geom As line,
ST_Distance(ad.geom, st.geom) As d
From ad, st
Where ST_DWithin(st.geom, ad.geom, 10.0)
Order By d
) As foo;
Based on this projected point, I need to calculate the length of street in both directions and width of street by making using of building polygons layer. The scenario can be visualized like this:
Visualization of the scenario
I am aware of ST_Length function but it returns the length of whole linestring rather than length 1 and length 2. Any advice to calculate lengths of street and width would be highly appreciated?
Thank you for looking at this - I'm sure it's a simple question but this is all very new to me and after a lot of internet searching my points are still in the sea!
I have a set of UK postcode data that I have converted into latitude and longitude. I also have a UK counties shape file.
The code that I have used to convert the latitude/longitude to a geometry point column is as follows:
ALTER TABLE colic ADD COLUMN longlat geometry(POINT,27700);
update colic set longlat = st_setsrid(st_point( longitude, latitude), 27700);
And this produces a column that has values as follows (I've only included a couple!):
"0101000020346C000048BF7D1D3867E83FC05B2041F1334A40"
"0101000020346C0000F085C954C1A8F7BFA1F831E6AE954A40"
"0101000020346C000020D26F5F07CEF4BFE3361AC05B504A40"
"0101000020346C00007D3F355EBA49F73FB6847CD0B3614A40"
The .prj from my shape file is:
PROJCS["British_National_Grid", GEOGCS["GCS_OSGB_1936",
DATUM["D_OSGB_1936", SPHEROID["Airy_1830",6377563.396,299.3249646]],
PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],
PROJECTION["Transverse_Mercator"],
PARAMETER["False_Easting",400000.0],
PARAMETER["False_Northing",-100000.0],
PARAMETER["Central_Meridian",-2.0],
PARAMETER["Scale_Factor",0.9996012717],
PARAMETER["Latitude_Of_Origin",49.0], UNIT["Meter",1.0]]
And I set its SRID to 27700 when I upload it using the PostGIS shapefile uploader.
In PG Admin, when I ask:
select st_srid(geom) from counties limit 1;
select st_srid(longlat) from colic limit 1;
I get 27700 for both.
But...when I try any spatial query I get no response, and when I load the layers into quantum, the point data are off the tip of Cornwall in the north Atlantic, and only represented as one dot on the scale of the counties map.If I zoom in on them, they are 'there', but just not in east anglia where they should be!
This is my first attempt at both SQL and mapping - I'm sure there is something really simple that I have missed.
You are mixing up spatial references (SRS). The SRS in the .prj file (aka SRID=27700) is projected eastings and northings, which have units of metres. This is not latitude and longitude! Furthermore, it is a deception to call a column longlat when it isn't for longitude/latitude coordinates.
If you try to insert latitude/longitude in a column with SRID=27700, the points will not behave as expected, e.g., they will be in the far bottom left corner of a map.
If you have lat/long data from WGS84 (SRID=4326), you can transform this to eastings and northings:
UPDATE colic SET
geom = ST_Transform(ST_SetSRID(ST_Point(longitude, latitude), 4326), 27700);
If i have a grib2 file that contains information for whole world (for some parameters) and I want to extract data from it using wgrib2 based on latitude and longitude given by user (client software to server). I tried following command but I am getting complete grib2 file only:
wgrib2.exe input.grb -undefine out-box 10:90 -10:10 -grib output.grb
Please tell me where am I going wrong? Thanks.
This is still the top hit on Google, so even though it is a bit old, here is a more detailed explanation.
First, you need wgrib2 from the National Weather Service Climate Prediction Centre. (The installation of that is straightforward, but not too well explained. See this page, or this gist for help.)
Next, you need to use the lola function (for LOngitude-LAtitude grid).
You need to give wgrib2 several arguments:
the grib file that has the data
the longitude information:
the longitude of the southwest corner of your bounding box
the length of the bounding box in degrees
the spacing of the points in this direction
the latitude information, the same as above
the latitude of the southwest corner of your bounding box
the length of the bounding box in degrees
the spacing of the points in this direction
the file name to write to
the format of the file to write (either bin for binary, text for simple text, spread for spreadsheet format, or grib for grib2).
For example:
wgrib2 input.grb 220:100:1 20:50:1 output.grb2 grib
will create an output file that covers north america (220 E - 320 E; 20 N - 70 N) at 1 degree intervals in both directions.
Rob
I used the following command to extract information from grib2 file.
wgrib2.exe input_file.grib2 -lola LonSW:#lon:dlon LatSW:#lat:dlat file format
assuming that we are having following co-ordinates for selection:
Top: (x0,y0) (x1,y0)
Bottom: (x0,y1) (x1,y1)
"LongSW"=x0, #lon = (x0~x1), "LatSW"=y0, #lat = (y0~y1).
and dlon and dlan can be kept as 1. 'file' is the output file name and format can be grib, csv, text etc.
Substitute above values in the command shown above and you should get the answer.
If your chosen longitude was 360 and latitude was 90:
wgrib2.exe input_file.grb2 -lon 360 90 > output_file.txt
I think you can also use cdo directly on grib for this
cdo sellonlatbox,lon1,lon2,lat1,lat2 in.grb out.grb
If the grib file is on a reduced gaussian grid you may need to specify that you want a regular lat-lon output. I usually convert the output format to netcdf myself using "-f nc" as I find it easier to process in other software.