All Questions

0
votes
1answer
26 views

Boundary point snapping post process - QGIS/PostGIS [on hold]

I have a set of polygons that have been digitised without snapping I want to achieve this after the event such that shared boundaries share common points. I have QGIS and PostGIS At present the ...
2
votes
1answer
31 views

Getting rid of cells of 0 values in raster using QGIS?

I have a DEM like below image. The black area shows 0-values. I want to remove cells of 0-values in the raster.   In raster calculator, I wrote con("demclip_re@1">0,"demclip_re@1") but it gives "...
0
votes
1answer
33 views

Automatic polygonising in QGIS? [duplicate]

I have multiple points and I need to create polygons that consist specific amount of points. How could i do this?
0
votes
0answers
31 views

QGIS data loss line shape

I have a problem with a mysterious data loss in QGIS 3.2.0. I have a line shapefile with multiple features in it. Eventually with no visible reason a big part of the lines vanished from the map. It ...
1
vote
0answers
11 views

GDAL rastercalc giving unexpected results

I have a raster file containing the following values: data values from 0 to 8488 nodata values values equalling -3.40282347e+38 The values equalling -3.40282347e+38 are presumably supposed to be ...
0
votes
0answers
28 views

Using import photos plugin in QGIS?

I have some geotagged photos saved on a network drive which I want to import into QGIS 3.2. I have installed the import photos plugin. I have gone through the import photos process and selected the ...
0
votes
2answers
36 views

OpenLayers adding/removing layer when checkbox is changed

I am trying to add and remove layers2 layer when checkbox is changed. How can I do it with jquery? Following my way i get: Uncaught ReferenceError: layers is not defined var wmsLayer2 = new ...
0
votes
0answers
13 views

Attach Textarea to Leaflet Draw Rectangle to drag with rectangle

I am trying to revive some of the code of Leaflet-Illustrate: It uses some Leaflet code that I believe is attaching hooks by using this: statics: { START: L.Draggable.START, END: L....
-1
votes
1answer
19 views

Creating weighted sum analysis using DEM and population data using QGIS?

I have a shapefile containing population points for Vietnam, and I am aiming to perform a weighted sum analysis using a Digital Elevation Model. Basically, I'd like to combine elevation, population ...
0
votes
0answers
24 views

Python error, creating training area

I'm using the last version qgis, 3.6 Noosa, I got the following error, while trying up to save the training signature class using scp plugin. Any suggestion. An error has occurred while executing ...
0
votes
1answer
21 views

Importing a georeferenced DWG/ DXF into QGIS

I work in an ecological consultancy and we would save money on mapping tiles if we could import DWG files into QGIS, they must be georeferenced however as we need to draw on various habitats ...
0
votes
2answers
25 views

Google Earth Engine exported image looks different from map rendered on screen

I am creating a composite image of Landsat 8 OLI of Okinawa and want to export the true color image to my google drive as a tif file. I was able to successfully download it, but the image (img2) looks ...
3
votes
3answers
192 views

Assign a specific color to vector layer based on RGB codes in attribute table

I use QGIS and have a geological map for a large area. I present this after ID codes based on the geology ("Geokartnr" in photo). I want to use international/nation color codes for each rock type, ...
0
votes
0answers
14 views

JAXA data 30x30 meter to 3D dxf/dwg [duplicate]

I imported JAXA data in QGIS 3.4.5 as a raster. I can extract contours etc., but when I export the contours to DXF all elevations are set to 0. Is there a way to keep the 3D data so I can use it for ...
0
votes
1answer
25 views

Slope is not consistent with the elevation of DEM and seems to be incorrect

I have a DEM image which shows the elevation is from approx. 81 to 103. I expected the slope should be 0-22m. However, the result from DEM-Terrain Model-Slope is from 2.5 to 13.2. Anyone knows why?
1
vote
1answer
15 views

Cutting area from polygon in Google Maps API? [on hold]

I found this example here. var map; function initialize() { map = new google.maps.Map( document.getElementById("map"), { center: new google.maps.LatLng(37.4419, -122.1419), zoom: 13,...
1
vote
0answers
19 views

In QGIS 3.6, where is the “Enable 3D renderer” vector layer property?

In QGIS 3.4 I could enable the 3D renderer for a vector layer (properties/3D view/enable 3D renderer). I can't find this option in QGIS 3.6 anymore. How can I activate this again for a vector layer?
0
votes
1answer
26 views

Different area values from Zonal Geometry and Tabulate area

I am working on Landcover map for Ghana. I calculated the area of each landcover type with Zonal Geometry in ArcMap. Then I wanted to know the area of landcover in each region (as in location). But ...
-1
votes
0answers
14 views

Calculating canopy model (CHM) using QGIS Raster Calculator?

Is it possible to calculate canopy model (CHM) with raster calculator from such input data? (DSM1 + DSM2 + DSMn) - DTM Or, is it necessary to merge DSMs first?
0
votes
0answers
19 views

Smoothing pixels only in a specific area [on hold]

I'm currently working with a DEM and wanna use the gdal_fillnodata tool to fill the nodata areas (which are 2 rivers and one lake) but there are a few default values in the DEM which lead to a bad ...
1
vote
0answers
13 views

QGIS 2.14 c++ standalone application crashes using QgsMapToolIdentify

lResultList.append(mpIdentifyTool->identify(lCoord.x(),lCoord.y(),QgsMapToolIdentify::TopDownStopAtFirst, QgsMapToolIdentify::VectorLayer)); leads to crash of app. It happens when layers provided ...
1
vote
0answers
24 views

Recovering shapefile with green question marks?

I have a shapefile with a green question mark in the ArcCatalog. The shp-extension in the shapefile has 0Kb size Is there any way to recover the corrupted file?
-1
votes
1answer
28 views

Writing Python script to delete multiple fields in multiple files but keep certain fields?

I am needing to be able to run a python script on a folder full of shapefiles to delete multiple fields in the attribute tables. But I want to be able to keep 3 fields (Crop_Type, Acres, and ...
0
votes
0answers
13 views

Using to_dms creating a second grid in QGIS [on hold]

I am trying to create a second grid layer. I currently have UTM grids on my map but want to put lat and long graticules for both x and y axis. How can I achieve this? I have been attempting to ...
-2
votes
0answers
17 views

Importing national address database downloaded from transportation.gov? [on hold]

US transportation.gov provides an open address database https://www.transportation.gov/gis/national-address-database/national-address-database-0 Anyone can download it free after agree the disclaimer....
0
votes
0answers
13 views

Access ESRI Addin Information From Custom DLL? [on hold]

I've been tasked with adding some additional functionality regarding Esri Addin information to an ArcMap custom DLL my company uses. So far, I haven't had much luck finding any documentation on how to ...
0
votes
1answer
19 views

Calculate distance from polygon to nearest existing line in geometric network, along network routes

In ArcMap 10.6, I have a parcels layer and a sewage lines geometric network for a small town. Many of the parcels are still undeveloped. In an effort to accurately assess them for tax purposes, their ...
0
votes
0answers
15 views

How do I find the closest distance to a line and then find the length of the remainder of the line to a point?

I want to measure the distance of a shape to a line and then follow that line all the way to a point and calculate the distance traveled. Here is my current map. I want to store that distance value ...
1
vote
1answer
31 views

Missing values for Choropleth Map in QGIS

I am creating a Poverty Choropleth from a vector file using polygons to represent each county in the United States. I joined the poverty Excel file with a text file to convert the poverty column from ...
0
votes
0answers
11 views

QGIS 3.4 (mac) std::bad_alloc error

I get the above error when trying to add a new raster or vector layer. Does anyone know how to correct it as the resulting projection is nowhere near where I need it.
0
votes
0answers
6 views

Using Mapsui, how do I create a new transformation class for coordinate system read from shapefile prj file?

How do I create a new transformation class compatible with MapSui.Projections.ITransformation interface using ProjNet4GeoAPI that reads the source coordindate system from a prj file. From Mapsui ...
1
vote
0answers
22 views

Summarise rasters then project, or project then summarise?

I'm working on an analysis that involves summarising a stack of unprojected (WGS84) global 30" climate rasters (various expressions of temperature and precipitation), and generating final output in an ...
0
votes
1answer
17 views

Collecting Moran's I output values in ArcGIS Pro?

I am running an iterator in ModelBuilder that ultimately takes the output from each iteration (a point feature class) and runs the spatial auto-correlation tool (global Moran's I). I have about 450 ...
-1
votes
0answers
14 views

Zonal Statistics on Multiple Raster Attributes?

I am running zonal statistics to determine the number of pixels of a given value within a given zone. So in this case, the example is CropScape, and let's say you had a radius and are trying to ...
2
votes
2answers
28 views

Get DD Lat and Lon from CRS EPSG:3111 - GDA94

I have a shapefile in CRS EPSG:3111 - GDA94 that I am trying to generate Lat and Lon, however when I use the field calculator and try to populate the lat lon I am getting values that I can't use as ...
0
votes
0answers
17 views

Wrong projection in QGIS 3.4 (mac) [on hold]

Why can't I get the right projection (EPSG 2193) in QGIS 3.4 (mac) with new rasters/vectors when I can using previous rasters/vectors?
2
votes
2answers
27 views

How do I combine geometries in a shapefile based on a grouping variable?

Here is a simple example. I have a shapefile of three US states: This is the code that creates the shapefile. library(USAboundaries) library(sf) library(dplyr) states <- us_states(map_date = "...
1
vote
0answers
14 views

Linear Regression on single image with multiple bands in Google Earth Engine

I have a single image with 3 bands representing different properties for water detection and a 4th band for reference (ground truth - water/no-water). I want to perform a linear regression using the 3 ...
1
vote
0answers
24 views

Obtaining coordinates of points on highways [on hold]

As a disclaimer, I'm extremely new to this field. I'm trying to obtain the geographic coordinates of points of fixed distance apart on interstate highways in the United States. I have been able ...
0
votes
0answers
5 views

Combining layers with mapshaper?

I have two layers of map data that I want to flatten into one. Bay Area Counties includes shapes for each county I want. California Place Names includes cities and towns. I used proj wgs84 to ...
0
votes
2answers
20 views

Joining selected fields from table to shapefile using ArcGIS Pro?

I have a line shapefile with 100+ fields and a separate dbf file with 100+ fields. I'd like to programatically (using arcpy and Python 3) eliminate all but 3 fields in both shapefile and the dbf, and ...
1
vote
1answer
25 views

Attribute Table Sort Disordered in QGIS?

I am using QGIS. I opened my attribute table in Open Office Calc and sorted the table by a column. I believe I had all the columns selected when I sorted. Now when viewing the layer, everything is ...
1
vote
0answers
22 views

Detecting checking/unchecking of rules in a rule-based rendering using PyQgis [on hold]

Is it possible to programmatically detect checking/unchecking changes of a rule in a rule-based rendering ? I found no indication of existing signals .. I got lost reading QgsVectorLayerRenderer ...
1
vote
1answer
18 views

Selecting multiple features with rectangle using ArcGIS API for JavaScript?

I am using ArcGIS API for JavaScript 3.7. I am trying to see if I can select features in the same fashion that shift+click and dragging lets you zoom into the map by drawing a rectangle. The trouble ...
0
votes
1answer
26 views

Writing Survey on Spatial data use? [on hold]

I am in the middle of building a survey to identify the environmental sectors environmental spatial data needs. I was hoping you could help with crafting the question on "What are your particular ...
4
votes
2answers
36 views

QGIS Random point inside polygon **but** - with minimum distance between points from different polygons

I am trying to generate random points in stratified area with 2 polygons. I want to generate 6 random points - 3 in each but to set minimum distance not only between points from same polygon but ...
0
votes
0answers
6 views

InfoTemplate moving between features with arrows is not click event. How to handle?

I have a click event that fires and sets content for the InfoTemplate when the feature is clicked. When a feature that overlaps with another feature is clicked, the InfoTemplate appears the ...
-1
votes
0answers
24 views

Overlay png image onto shapefile in QGIS?

How can I overlay a png file onto a shapefile in QGIS? I loaded both into QGIS and then tried using the Georeferencer tool to assign coordinates on the png image but then I get stuck on overlaying the ...
-2
votes
1answer
25 views

Calculate the total area from two intersected polylines

If two polylines intersect with each other and there are more than 2 intersect points, there is more than 1 closed area will be created. How can I get these areas as polygons in ArcGIS?
0
votes
1answer
19 views

Add and Calculate Fields of Iterated Annotation Classes

I'm have difficulty with my script Arcmap v10.5.1. I get a syntax error on line 8. My question is: Can I calculate the Added field from an existing field within an iterated value? If so, what's my ...

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