All Questions
161,726
questions
0
votes
1
answer
42
views
GeoJSON layer development [closed]
I would like to draw war control lines, and am trying to find a way to export umap or other control zones to GeoJSON.
What possible tools could I use to do that, and what geo-polygon tools would allow ...
0
votes
0
answers
17
views
Validity of Z-score transformation of ndvi raster [closed]
I am assessing the vegetation health of reclaimed oil and gas leases in annual crop land using uav based multispectral (ndvi) mapping and zonal statistics (qgis). I've been mapping sites for 3 years ...
- 211
1
vote
0
answers
31
views
Showing feature count when exporting map with qgis2web Plugin
I am trying to include the feature count when using the qgis2web PLugin. I have a point layer and I simply want to show the number of features for each specific field.
This is what I see in the layer ...
0
votes
0
answers
40
views
Terra/geodata world map cropping issues, possibly due to truncated extent
Cropping geodata world map across Greenwich (not exactly though) or close to the poles gives a "Topology Exception" error on RStudio (Posit) cloud, although not on RStudio desktop. Also, the ...
- 3
3
votes
1
answer
63
views
Counting points from layer at map extent with QGIS expression
I want to create an expression in the QGIS 3.28 dashboard layer that counts points on a specific point_layer and with a specific value that is displayed in the current map_extent view
aggregate(
...
- 405
0
votes
0
answers
12
views
Buffer Error when using xarray
When I tried to using python package "xarray" to read grib files, I got an error. It's quite weird, because I had did it successfully yesterday.
This is my code:
import xarray as xr
import ...
- 36
1
vote
1
answer
63
views
QGIS: Model Designer: Specify the order in which algorithms are run
I am trying to build a complicated model in the model designer. It will have, once I'm done, probablyy around 20-30 conditional branches. The branches select and extract points from a point layer with ...
- 63
1
vote
2
answers
41
views
How to export an IDW DTM as a GeoTIFF file in R
I have loaded both raster and lidR packages within RStudio and I am trying to export the IDW DTM files but have been receiving errors about 'format'. I have exported a TIN DTM already however with IDW ...
- 13
2
votes
1
answer
97
views
Generating DEM that gives realistic contour
I am quite new QGIS user. I have point data from the field and I generated DEM and contour. However, the contours are a bit unrealistic. I have attached the image. The green contour is the contour ...
- 125
0
votes
0
answers
89
views
Downloading polygons from Wikimapia [duplicate]
Is there any way to download a polygon from Wikimapia? There's several I created a few years ago and would like to import to Google Earth as .kml.
Most of the answers supplied direct to broken links ...
0
votes
0
answers
25
views
Best map projection for buffers and Euclidian distance in Cox's Bazar, Bangladesh (20sq.km) [closed]
My study region is a 20 square kilometre area in Cox's Bazar, Bangladesh, and I am using R. I'm wondering which map projection would be the most accurate for measuring linear distances between points, ...
2
votes
1
answer
63
views
Adding coordinates to point feature with missing location
I have received some data from a third party that includes some point and line features that have no location information. I have the coordinates which I would like to use to provide that location ...
- 29.6k
0
votes
1
answer
73
views
Error when creating polygons with turf.js from existing GeoJSON polygon rings
I'm getting the following error: Uncaught (in promise) Error: Each LinearRing of a Polygon must have 4 or more Positions. when trying to use @turf/turf module:
async function selectSubregion(e) {
...
- 101
2
votes
2
answers
56
views
Filter out point layer from Quick OSM using raw query
I want to be able to create an OSM Query for 'highways' and 'buildings' only (no OSMQuery Points) in the Model Designer, so I need to be able to understand all of the code required to create an OSM ...
- 75
0
votes
0
answers
11
views
NTRIP Caster, NTRIP client and NTRIP sever building (WEB APPLICATION) [closed]
Iam trying to build a web application for NTRIP Caster and Client and server. Can you tell what are the features I should include and where to find the data set to implement
-2
votes
0
answers
17
views
I set a list of Sentinel-2's images for each year but the result show that my images have 0 band [duplicate]
I'm trying to make a list of Sentinel-2 image for each year from 2015-2023, each of output layer are the years. But the result shows image doesn't have any bands. How can i fix it?
My code:
function ...
0
votes
1
answer
17
views
Changing EURO-CORDEX so it can put in the same plot the data and the countries shapes?
I'm working with data from the Copernicus climate change forecast and I downloaded the data of predictions for rain and precipitations from here link. When I import the data as raster class into R I ...
- 1
2
votes
1
answer
25
views
Trouble with PostgreSQL pgRouting function pgr_dijkstraCostMatrix
I am trying to use the pgr_dijkstraCostMatrix function in pgRouting for PostgreSQL to find the shortest paths between points in a road network. However, I keep encountering an error indicating that ...
- 21
0
votes
0
answers
19
views
Using ArcGIS 10.8 , Georeferenced stops working when I put a coordinates to a point [closed]
When I georeferenced and after putting coordinates on the first point and the ArcGIS stops working and I got an error message, I tried to change computer but this has nothing to do with it. Sometimes ...
- 1
0
votes
0
answers
16
views
CrossTabManagerError appears in creating changes map while using MOLUSCE Plugin in QGIS
I'm using QGIS 2.16.0 Wein and the Plugin MOLUSCE(ver. 3. 0. 13). Now I'm trying to create a change map, but get the following error.
Traceback (most recent call last):
File "C:/...
0
votes
0
answers
25
views
AutoCAD floor plan to categorized polylines usnig ArcGIS [closed]
I'm still new to ArcGIS and I want to find a way to convert CAD drawings to groups of closed polylines (polygons in GIS) using ArcGIS Pro or any other software that will get the job done.
I expolred a ...
0
votes
0
answers
50
views
Image not showing any bands
I'm trying to make a list of Sentinel-2 image for each year from 2015-2023, each of output layer are the years. But the result shows image doesn't have any bands.
How can i fix it?
My GEE source: ...
-1
votes
0
answers
22
views
Google Earth viewshed tool
How accurate is Google Earth viewshed meant to be be?
My results in ArcGIS using UK OS elevation data and visibility tool are fairly different from the 'viewshed' on Google Earth.
- 17
-1
votes
0
answers
33
views
How do Tissot's indicatrix look in a gnomonic projection?
For a mathematical problem (no homework)
A map is given with Tissot's indicatrices.
How can I conclude if the map is gnomonic or not?
(Just to be complete , a gnomonic projection is a projection were ...
- 1
0
votes
0
answers
49
views
SQL query in QGIS 0 rows affected [closed]
I am new in QGIS.
I have in QGIS vector layers loaded. Two of the four layers have the same CRS. For another two, I must transform between the two CRS. Now when I am doing some query in SQL between ...
0
votes
1
answer
29
views
CRS for georeferencing TCP flight maps of Spain
I want to georeference TCP flight map of Spain.
It says: Lambert Conformal Conic Projection
Standard Parallels 41dg 20' and 46dg 40'
Convergence factor 0.69491
QGIS does not offer this CRS and even ...
- 91
0
votes
0
answers
28
views
Hans Der Kwast - Derive Streams and Catchments Model (r.to.vector not outputting file)
I'm using the model created below and following the steps from 17:00 onwards
https://youtu.be/ZC0skH4ifsI?list=PLeuKJkIxCDj2Gk0CkcJ-QeviE41aMZd-5&t=1021
I've followed the osgeo4 installation steps ...
1
vote
2
answers
67
views
GeoPandas to pull attributes from polygons based on point coordinates
I have a shapefile with a large grid of rectangular polygons (approximately 6M polygons) and I would like to pull an attribute value from a polygon in this set based on an arbitrary point (x,y) ...
- 41
0
votes
2
answers
45
views
Referenced ArcGIS Pro 3.1 toolbox renamed and empty toolbox created in its place
GIS program manager here. I am experiencing a serious problem. It occurs when starting new projects in ArcGIS Pro from a template which includes our "program toolbox" (aka Default.tbx) ...
- 1
0
votes
0
answers
9
views
How to use folium marker on click event to draw other markers on the map
I'm trying to build an app with Python to generate markers when ever I click on an initial marker. I tried using folium but it's not working for me.
I tried editing in the generated HTML file but it ...
0
votes
0
answers
19
views
Error using Terra in R to combine Geometries using combineGeoms
I am trying to eliminate polygons in a multipolygon that have an area smaller than x. This is my code:
v = terra::vect(f)
area <- expanse(v)
th <- area < 25
x <- combineGeoms(v[!th], v[th])...
- 755
0
votes
0
answers
27
views
How to calculate percentile distribution from a given radius [closed]
I have been working with a dataset from the gov't of Canada for lake sediment geochemistry. One of the worksheets displays the data as "Values for each element ranked as percentile with respect ...
- 1
0
votes
0
answers
13
views
How to color correct a mosaic raster
I am building a composite image to create a wetland predictor variable and I will then run RF to classify wetlands.
The first step is to mosaic Sentinel-2 images (4 bands, RGBI) and then create a ...
- 375
2
votes
1
answer
37
views
QFieldSync how to synchronize from QField to PostGIS data
I am using QField with QGIS to collect data in the field, in offline mode. My data are stored in a PostGIS database I manage. I used QFieldSync to package my QGIS project and was able to open it on my ...
- 184
0
votes
0
answers
11
views
Syncing QfField with Android
I've been running into syncing errors when trying to view new files I've uploaded to my desktop QGIS project (synced with QField Cloud project) on my Android device. I'm unable to view files and a ...
0
votes
0
answers
31
views
Single Sign On between ArcGIS Online and GeoServer
I'm trying to add WMS layers in ArcGIS Online without the need to sign in again to GeoServer. To achieve a Single Sign On, I have federated ArcGIS Online with our Okta IdP using Open IDC protocol. We ...
1
vote
0
answers
34
views
Creating Streams from endpoints and NHD Stream Layer using ArcGIS Pro with Spatial Analyst
I have a dataset for instream flow water rights that delineates the length of stream based on upstream and downstream endpoints and the miles of stream. I'm trying to create a GIS layer for this ...
- 11
0
votes
0
answers
20
views
Reputation required for commenting on posts [migrated]
I would like to ask a follow up question to a post without posting the same question again in fear of it being marked as duplicate. I fear I am trapped in a vicious cycle unless I come up with a ...
- 1
0
votes
0
answers
22
views
How to label points clockwise? [closed]
I have data that has X/Y that plots. I can do Near analysis, sort and delete duplicates to get something similar but not sorted in a clockwise manner. Is there any tool or Arcpy process that I can use ...
- 31
3
votes
0
answers
41
views
Selecting features based on minimum overlap with another layer in QGIS
I have a "sites" vector layer with 300 polygon features and a "heathland" vector polygon layer, showing the locations of heathland areas. I am looking for a way to select all ...
- 59
0
votes
1
answer
35
views
Raster polygonization and number of classes
I created 4 height classes on a raster:
( "diff_2019-2016@1" <= 0) *0 +
("diff_2019-2016@1" > 0 AND "diff_2019-2016@1" <= 0.5) *0.5 +
( "diff_2019-...
- 899
0
votes
0
answers
32
views
Client interactive web map [duplicate]
i am new to gi’s and i have been using your app for a couple of weeks. I want to ask how i can make a webmap were the client can add points and details about them. I have used the qgis2web plugin ...
0
votes
0
answers
20
views
ST_ValueCount for multiple bands
Given a multi band raster, I would like to summarise the distinct combinations of values found, in a manner similar to ST_ValueCount, but across all the bands rather than a single band at a time.
...
- 3,297
1
vote
0
answers
43
views
Extracting Latitude and Longitude Coordinates from PBF Files
I aim to retrieve and handle PBF files sourced from an online map. The provided link exemplifies a PBF file:
https://tiles.raah.ir/tiles/low/16/42122/25807.pbf
Upon loading this file into QGIS, the ...
- 11
1
vote
0
answers
44
views
Separating intersecting lines in QGIS
I have a project in QGIS where multiple cables follow different paths using specific points as vertices, and sometimes the cables end up crossing over each other.
I would like to perform a ...
- 11
0
votes
0
answers
18
views
How geolocalisate a new image with a polygon (JSON file)
I am new using QGIS. I got an Sentinel-1 image from Copernicus I downloaded it as TIFF. I did Python code to detect water so now l have a new plot. I would like this plot gets the same coordinate than ...
- 1
0
votes
0
answers
14
views
Some metadata doesn't show up in manually created .shp.xml in QGIS?
I'm creating shapefiles in Python using geopandas from processed climatological information. This a simplified version of the code I'm using to generate the shapefiles:
import geopandas as gpd
from ...
- 101
-1
votes
0
answers
30
views
Precautions that should be taken to calculate the difference between two digital terrain models
I use a digital terrain model.
I want to calculate the difference between the two rasters,
like this with the raster calculator:
"raster1@1" - "raster2@1"
However, I realize that ...
- 899
0
votes
0
answers
8
views
Values in second columns of GPValueTable Parameter reset after tool is ran
I am trying to create a .pyt python toolbox tool in arcGIS pro and the issue I'm running into is that Values in second columns of GPValueTable Parameter reset after tool is ran.
The parameter created ...
- 23
1
vote
1
answer
52
views
How to merge sample points that are within a certain distance of each other and calculate mean attributes values for merged points in QGIS?
I have a data set like the following in .csv:
sample
latitude
longitude
variable1
variable2
variable3
A
37.18
-115.85
1
0
0
B
37.18
-115.85
1
0
0
C
37.18
-115.85
1
0
0
D
39.44
-117.66
0
1
0
E
39....
- 53