A spatial operation in which two or more maps or layers registered to a common coordinate system are superimposed, either digitally or on a transparent material, for the purpose of showing the relationships between features that occupy the same geographic space.

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3
votes
1answer
405 views

Area overlay of census on Zip Code

I have census block data polygons. I want to overlay them over Zip Codes (larger polygons) in order to estimate the population in the Zip Codes. Or overlay buffers around toxic waste sites over census ...
0
votes
0answers
13 views

How to hide overlays in Leaflet layerControl if geojson var not found?

i would like to perform a specific task: i have a set of geojson layers, loading features from local files. i have the layercontrol on the map showing available layers to show/hide now, regarding ...
2
votes
1answer
30 views

strange banding in output raster after weighted overlay

I am trying to conduct a weighted overlay. I have two rasters, one is a continuous slope raster that I reclassified to have 6 classes (8bit signed integer), and one is an elevation raster that I also ...
0
votes
1answer
21 views

Image source of world political map for Google Maps overlay in Android?

I have searched a lot. But I am not able to find some high resolution image of world map showing countries in different colors without label, which I can slice and use to create tile overlay in my ...
0
votes
2answers
122 views

I can not override my WMS layer in Google Maps as a base

I can not override my WMS layer in Google Maps as a base: I have a WMS layer in geoserver am using openlayers to show them. Calling only works WMS layer:   see my code, I am using using the bounds ...
1
vote
1answer
48 views

Erasing overlay geometry with in the feature class..!

What is the best practice for erasing overlay geometry? My scenario is: I have a polygon layer with 1000 features. i need to create a tool from model builder that select polygons with user defined ...
0
votes
2answers
30 views

OpenLayers + Geoserver problem with wfs projection

In geoserver i have a layer in EPSG:26191. In OpenLayers i add it on map as WFS: markerLayer = new OpenLayers.Layer.Vector('Markers',{ strategies: [new OpenLayers.Strategy.Fixed()], ...
1
vote
0answers
18 views

How to overlay an NOAA nautical map as a layer in QGIS [duplicate]

I am new to QGIS and am doing some work for a friend. He is hoping to overlay an NOAA nautical map as a layer in QGIS. My only real experience is with ArcGIS. He is looking to do something similar ...
0
votes
0answers
19 views

Overlaying Line (Vector) Layer on Raster Zones?

I will make my best attempt to clearly explain my problem. I am using ArcGIS 10 I have a raster layer with 3 values that make up zones. For the purpose of this example, lets say these zones are ...
1
vote
1answer
41 views

Apportion Neighborhood Information to Census Tracts

I have a shapefile of census tracts and another shapefile of "neighborhoods" with values that I need to have joined to the census tracts. I know I need to apportion the area of the neighborhood ...
0
votes
0answers
10 views

Is the geoxml3 javascript API compatible with the mapstraction API?

I am getting ready to revamp a google maps application and I was considering utilizing mapstraction. I am currently using all google maps js, with a kml layer overlay, but obviously by using the ...
1
vote
2answers
281 views

Transforming a google maps overlay to fit a Ordnance Survey projection

I am currently in the process of creating a map with some administrative boundaries on it. The base map I am using is an ordnance survey map 1:10000. I downloaded an administrative border as a .kml ...
0
votes
2answers
353 views

OpenLayers: Strange Tiling Issue (Checkered, white and grey) when panning around map

So this strange tiling issue is only occuring when moving around the map. Some things to note: 1) You can see the markers, airplane icon, and flight paths. These are all overlays, where the actual ...
0
votes
1answer
18 views

Kml not overlaying onto Google Map

I created a basic dashboard with MVC 4, visual studio 2012, The dashboard displays a Google map. Here is an image of the dashboard: My intention is to be able to take this Kml file: And ...
5
votes
1answer
425 views

Generate tiles for google maps overlays

I am trying to show some information on Google Maps which would be in the form of translucent circle overlays. The problem is that some circles overlap, which results in increased opacity and blending ...
0
votes
1answer
42 views

Selecting raster data by location: for raster and feature class data

I have rasters covering certain spots in my environment, I'm looking for a way to extract the values which occur at locations which are defined by a selection of feature layers. I've tried with the ...
0
votes
1answer
43 views

How to overlay a jpg onto a google earth image?

I have produced a model from an online engine , and it is in a google earth picture. I want to georeference the below picture and apply the boundaries here on my google earth image. I'm using QGIS2.2. ...
0
votes
2answers
35 views

Frequency analysis and overlay analysis

Am new to gis and I hope to find help here. I am working on a research that requires that I overlay conditions of drainage systems and quality of healthcare in a coastal state to get areas which have ...
1
vote
1answer
426 views

Merge two maps with OR operation in GRASS

I have two vector maps. The two maps cover the same area but are split up into polygons differently (i.e. if you were to imagine one map placed above the other, the lines defining the polygons would ...
0
votes
0answers
19 views

Spatio-temporal Overlay

I have a SpatialPointsDataFrame that lists satellite-detected fires (firesutm), including location and date. I also have a SpatialPolygonsDataFrame with county boundaries (countyutm). I would like ...
0
votes
0answers
62 views

QGis, how to overlay and correctly position and scale a KML and image onto a Google base map

Being totally new to the entire GIS subject I managed to install and get runnning QGis (2.2.0 on Mac) properly, get my Google Maps showing (I set the the CRS to WPSG:3857) and I also got my KML file ...
4
votes
1answer
81 views

Show markers only at certain zoom levels

I'm building a cycle touring map in leaflet.js, with subjective information overlaid as markers, along the lines of "this is a great road", "this town is quite nice" etc. To avoid information ...
1
vote
1answer
23 views

Combining several rasters before r.surf.contour?

I have been trying to generate an elevation model from contour lines using first v.to.rast.attr and then r.surf.contour. Generally, it works pretty well, execpt for one issue. My data contains a lot ...
1
vote
1answer
46 views

Overlap or intersect two choropleth [closed]

I have two choropleth of the same area but with different concentration data and I need to overlap them. My aim is to highlight the areas of intersection between the points with the highest ...
0
votes
1answer
58 views

Weighted Overlay with “nodata” cells

I´m currently conducting a suitability analysis with the weighted overlay function. One relevant criteria is the proximity to highways. If the wind turbine is located up to 300 m away from the ...
1
vote
0answers
62 views

Problem with polygon overlay in raster stats using gdal

I am using the raster_stats module in python to calculate the mean carbon value for different sets of polygons. Here is the code that I am using: africa_sat = ...
1
vote
1answer
68 views

Stamp out and transfer values from one overlayed vector layer to another

I have a vector layer with administrative boundaries and another vector layer with postal code boundaries, which are more precise/smaller entities/objects. I now want to transmit the values of one ...
0
votes
0answers
15 views

Openlayers and Geoserver: Google Maps and WMS Overlay [duplicate]

I'm trying to overlay a WMS layer in Google Maps. My coat is already projected in EPSG: 3857 and has prj file. I used the following command in postgis to confirm: the result EPSG:3857 SELECT ...
1
vote
0answers
30 views

Calculating Percent Overlap Between Distribution Maps

Hello there, I am currently trying to calculate the percent overlap (basically the total amount of overlap where these two species come into contact) between Lithobates catesbeiana (first image) ...
1
vote
1answer
42 views

Extract information of a raster overlayed on another raster with a lower resolution directly in python

I have two aligned rasters with the same extent, one has a resolution of 5 meters and the other of 125 meters. I would like to place the 5 meter one over the 125 meter one and assign to these smaller ...
1
vote
1answer
55 views

How to combine Boolean and Fuzzy logic?

So I have a set of 5 Fuzzy Memberships and a polygon feature class, to which I already added a yes/no field. For the final map, I need to combine/overlay all Fuzzy Memberships and the rasterized ...
2
votes
3answers
1k views

How to find most common classification within buffers?

I have a point shapefile that identifies the location of incinerators in England and an output area classification shapefile. I have created a buffer for all the points in the shapefile because i ...
0
votes
1answer
18 views

How to select the identities of a layer present just in one identity of another layer

I'm a student approaching to QGIS 2.0.1-Dufour. My goal is to know how much identities of a layer are present just in one identity of another layer. I tried both with the tools "spatial query" and ...
1
vote
1answer
55 views

QGIS 2.0: move basemap by hand in order to achieve overlaying with a point layer

I am an environmental engineer and the aim of my QGIS 2.0 project is to visualize the results of a sewage water system inspection. In a first step I included the hoppers from a csv file and added a ...
1
vote
2answers
59 views

Historical maps as cylindrical projections

Objective: I want to overlay old, historical maps on top of Google Maps. According to Wikipedia, Google Maps uses a variant of the Mercator projection, a close relative of cylindrical projections. ...
1
vote
0answers
69 views

QGIS plug-in equivalent of ArcGIS's Spatial Analyst Tools -> Overlay/ Weighted Overlay

Specifically I have 12 .bil raster files that show monthly global mean minimum temperature. I file for each month. I want to combine these to create an ANNUAL global mean minimum temperature. In Arc I ...
1
vote
0answers
115 views

Replace google map MARKER with HTML element

I want to add a custom HTML element (that can become transparent dynamically) instead of a marker. Basically my html object would be a cirle (or rounded pin) with a picture of users in the middle. ...
0
votes
0answers
26 views

Overlapping of two layers in MySQL spacial extensions

I have been into GIS for almost a week now. Right now, I am learning MySQL spacial extensions. I have a question regarding the functions MySQL provides: I have a table that consists of LineString, ...
0
votes
0answers
48 views

Removing multiple categories from GRASS vector feature

Pardon my lingo if this is not entirely correct - I am a software developer, not a GIS person. We're working a project that uses v.overlay to merge a map of slopes with a map of soil tests to produce ...
0
votes
0answers
115 views

How to import AutoCAD .dwg files as overlay on map in Drupal (using OpenLayers)

I am using OpenLayers on my Drupal site. The request is to import AutoCAD .dwg files as an overlay to maps on the site. Is this possible and how? I found the OpenLayers Editor for Drupal, am I on the ...
0
votes
0answers
45 views

Not a valid data source of kml created from image overlay by Google Earth

I did image overlay in Google Earth and saved it as kml file. But it was showing me that it is not a valid data source when add it as vector(kml) in Qgis 1.8.0. Any solutions? Thanks!
0
votes
1answer
39 views

Calculate best area with overlaying multiple layers buffer shapes

I am using QGis and I have a set of 20 layers with buffers. I'm interested in where they overlap most and I want to create a single layer that shows which are the places where they overlap most and ...
3
votes
1answer
230 views

remove land area from marine region polygons

In my pursuit to merge multiple polygons for the purpose of calculating the surface area of marine species distributions, using shapefiles from Marineregions, I am now trying to remove potential land ...
0
votes
0answers
20 views

No values in overlay tab, only in diagram tab

I have basically the same issue like in this post. I joined a table to a .shp with the intention to display those values (integers) as a column overlay. Producing pie charts (Diagram tab) works fine, ...
2
votes
2answers
114 views

Identify parcels that have two types of land use

I have two polygon layers in a geodatabase. One layer is land parcels. The other layer is land use. I want to identify the six largest parcels that contain both "upland forests" and "wetlands" (i.e. ...
2
votes
3answers
198 views

Produce a list of polygons that a line crosses

I have a polyline feature class and a polygon feature class. What I want to do is add a field to the lines that lists all polygons that touch the line. This is effectively performing a ...
1
vote
2answers
82 views

What is the most efficient method to delete points?

I have a script that takes a point featureclass (FC) through the following workflow: Select points that lie within individual polygons From the selected points within each polygon, randomly subset ...
1
vote
2answers
52 views

Why does my gpx layer go to the wrong spot even if they have the same CRS?

Help! I am a QGIS beginner with a big problem! I am trying to load a gpx file from Garmin into my map. The project CRS is WGS 84, and the incoming data is in CRS WGS 84. When I look at the bottom of ...
0
votes
1answer
120 views

How to calculate proportional data for a polygon by taking attributes from other polygon

I have a features class which has polygons in it. I also have a Block group level data for demographic variables like population. Now when I overlay the polygon on the block group level data to find ...
2
votes
2answers
4k views

How do I overlay a KML on leaflet 0.4.4

I am using Leaflet 0.4.4, I have a KML I would like to overlay on the map, how do I go about doing this? Edit: I am already aware of https://github.com/CloudMade/Leaflet/issues/14, which directs ...