Questions tagged [scale-factor]
The scale-factor tag has no usage guidance.
35 questions
0
votes
0
answers
12
views
Landsat 8 C2 L2 FOR NDVI
When I download Landsat 8 C2 L2 image from USGS and apply directly NDVI formula the value is ok it is in range -1,+1 while where I am applying scale factor which is (0.0000275)-(0.2) for each band ...
1
vote
1
answer
161
views
Scale features based on field value [duplicate]
I have a polygon dataset of 100+ tree canopies - all different shapes and sizes, which I am required to scale by a specific factor to project growth over a number of decades. All canopies have ...
- 23
0
votes
0
answers
1k
views
How do we get 0.9996 as scale factor in UTM projection. Want this info to perform grid to ground conversion
I am working on a Site Calibration project that performs grid to ground conversion with some additional calculations. It's almost ready but I am having issue with calculation the scale factor. I am ...
- 21
1
vote
0
answers
109
views
Different NDVI ranges caused by multiplicative scale factor and additive offset
I am trying to calculate NDVI using Landsat 8 Collection 2 Level 2 data. My problem is that, before applying the scale factor and the offset, NDVI range is correct. After applying the scale factor and ...
- 133
1
vote
0
answers
31
views
What are the band units of L8C2L2 before applying the scale factor?
Bellow there is an image which shows "Collection 2 Landsat 8 Level 2 Science Products Band Specifications". When I use the multiplicative scale factor and the additive offset on Band 10, I ...
- 133
0
votes
0
answers
72
views
How do I generate a grid where each cell is equal to 500 px at 1:250k scale?
I worked this out once but I forgot how I did it. Somehow the grid size created a whole number of cells.
I have a map with the following extents:
xmin = -20037508.3427892439067364
xmax = 20037508....
- 21
3
votes
1
answer
187
views
Scaling polygons in vector grid around polygon centers in QGIS
I have a aerial image with a vector grid overlaid in QGIS. Is it possible to scale the individual polygons (scale all of them by the same size) around their individual centroids? For example, to cut ...
- 61
3
votes
1
answer
510
views
Scale Factors application not working on GEE PyQGIS
I'm trying to load some Lansadt 7 Collection 2 images on a QGIS project trought the following script:
import ee
from ee_plugin import Map
ecorregiones = ee.FeatureCollection('users/paullcfias/...
- 65
1
vote
1
answer
71
views
Sizing Diagram pies by quantity
I am using QGIS Zurich 3.12.
I have records for some 35 species. The records (by year), initially, relate to four (point) locations. Two of the points have records for most of the species. The other ...
- 101
3
votes
3
answers
2k
views
Issue with scaling factors for Landsat Collection 2 Level 2 data when calculating NDVI
I'm trying to calculate the NDVI for a scene, and I've downloaded Landsat 8 OLI/TIRS Collection 2 Level 2 data, which means it has already been processed to surface reflectance.
The scaling factors ...
- 31
0
votes
0
answers
966
views
How do I accurately resize a map to match the scale of the next map I want to build a bigger map from?
I have exported a group of maps that I want to tile together in Illustrator. Since the maps are not of the same scale I tried calculating the factors between each scale to the largest number of map ...
3
votes
1
answer
515
views
Statistic for measuring (local) autocorrelation of ordinal data
I have a spatial data set with a bunch of variables in nine-level ordinal scale.
I want to calculate (local) spatial autocorrelation for each of these ordinal scale variables.
I've been using ...
- 53
2
votes
1
answer
380
views
Is having rectangular cell sizes in a raster bad (after resampling)?
I used rasterio to scale a raster I have to a new resolution. It was at (5.0, 5.0) resolution, and I wanted to make it (15.0, 15.0).
However, the resulting resolution is not square anymore.
Here's ...
- 289
1
vote
0
answers
177
views
Scale data upon WCS request?
I am serving a set of GeoTiffs through GeoServer.
In order to save disk space I have multiplied my original 32 bit floating point data by a factor 1000 and then rounded to the nearest integer, so I ...
- 143
3
votes
1
answer
573
views
Relation between scale factor and standard meridians/parallels
Let's use transverse Mercator with a custom zone, with central meridian 30, the zone is 3 degrees wide at the equator, with a scale factor k=1, it means that the cylinder touching the spheroid along ...
- 343
1
vote
0
answers
18
views
Using correct coordinate system in ArcMap? [duplicate]
Im doing fyp on sabah & saraawak map. it came without prj file. i manage projected it and its allign to each other. but now i think the map is too small. as in the whole continent is within few ...
- 11
6
votes
1
answer
1k
views
Scaling more than 1000 polygons in QGIS
I have more than 1000 polygons, but they do not have the correct size and location. I have a table with the correct coordinates (centroid) "x, y" and different scale factor for each polygon....
1
vote
1
answer
1k
views
add scalefactor and offset to NetCDF
I am converting some NetCDF files from Float32 to either 16bit or 8bit to safe space on a server.
Since I Originally created these NetCDF using GeoTIFF´s this is where I apply the conversion before ...
- 421
1
vote
0
answers
236
views
How can I scale a feature referring to the area? [duplicate]
I'd like to scale features with a scale factor. With the scale tool of the editor toolbar it is possible to define a factor but then every single line of the feature is scaled by this factor. However, ...
- 19
3
votes
1
answer
1k
views
PostGis Scaling for Polygons at a fixed center location
I need to enlarge/expand a 2D polygon at its fixed location (lat,lon) with a constant scale factor in order to retrieve the surrounding area with the same shape as the origin polygon.
What PostGIS ...
- 51
2
votes
1
answer
285
views
Getting more details by zooming in web-client?
today I've setup a qgis server and web client on my windows machine.
Here is my WebClient.
Now I'd like to test out everything.
I tried to zoom in to the map, but it just stops by 1:2257 . I need ...
- 21
1
vote
1
answer
422
views
Standardizing layers in R?
I am using R to develop species distribution maps.
Since I standardized my covariates during the modeling process, I needed to transform the country-wide data (i.e. riv) using the same values.
I ...
- 187
2
votes
1
answer
6k
views
How do I get a specific scale/zoom level in the QGIS canvas?
I have a map project with CRS = NAD83 zone 13N. The canvas will zoom to 1:144,447, 1:288,295, 1:577,790, etc. The values in the dropdown, on the other hand are 1:100,000, 1:250,000, 1:500,000, etc. ...
- 6,043
1
vote
1
answer
2k
views
How to call Legend end points of multiple layers published from Geoserver?
I have map services published from ArcGIS server being called from Angular- Leaflet app and we are displaying the legend (controlled through map controls) from
https://pxxxx.com/arcgis/rest/services/...
- 789
2
votes
1
answer
693
views
QGIS 2.12.1 - Problem with Size Assistant in „data defined override“ Button - Error message
While trying out the Size Assistant feature I encountered a problem.
I´m working with this csv Table:
I tried to resize the Point Size based on the field „Anzahl Objk“ and to do this I went to „...
- 389
1
vote
0
answers
1k
views
reading raster without making QGIS apply the scale factor to the raster
Since QGIS multiplies the image with the scale factor when reading, it messes up the image if the scale factor is not properly defined to the data as QGIS expected. For example, I am reading MODIS ...
- 139
0
votes
1
answer
304
views
LAStools (3D Analyst) scale factor application
I'm trying to use the las2las (transform) module from the LASTools toolset to apply a scale factor to an LAS dataset. The problem is that the client wants us to apply the scale factor from a known XY ...
- 11
1
vote
0
answers
296
views
Query to merge simplified polygons according to the map scale-factor [closed]
I'm trying to construct a view in PostgreSQL that simplify polygons according to the map scale-factor. Basically I was reading this thread http://linfiniti.com/2011/06/scale-dependent-generalization-...
- 325
2
votes
0
answers
285
views
DPI Dependent OSM Tile Rendering
We have built an OSM Tile Server following the instructions at
http://switch2osm.org/serving-tiles/building-a-tile-server-from-packages/
The tile server is rendering tiles, but the street names on ...
1
vote
1
answer
1k
views
Using a Local Datum Plane (LDP) scale factor within ArcMap?
I have a CADD drawing that uses a Local Datum Plane (LDP) scale factor of 0.99991199. When I add the drawing to ArcMap without taking into account the scale factor, the drawing appears to the east of ...
- 9,141
7
votes
2
answers
11k
views
Influence of the scale factor on the projection
I'm currently reading documentation about map projections to understand the source code of the Proj4 project.
The scale factor is named in a variety of sources I read. This sources explained its ...
- 184
1
vote
0
answers
178
views
Scaling features based on an attribute [closed]
I would like to scale polygon features by a specific factor I have calculated for each feature in a feature class.
I know of the Scale tool, however it only allows for manual entry of a scale factor ...
- 3,240
4
votes
2
answers
3k
views
Easy way to render TileMill tiles in retina mode with Leaflet?
I have a few quick little map websites that run straight off TileMill, without pre-exporting. They usually have code like this:
L.tileLayer('http://example.com:20008/tile/MyMap/{z}/{x}/{y}.png',
{})...
- 5,710
1
vote
1
answer
2k
views
Using ogr to calculate distance is returning incorrect results away from equator
In an answer to Looking for Python module to do lat lon calculations @ustroetz provided some sample code for use of ogr to do lat/lon distance and point in polygon calculations.
I've created a Python ...
- 332
0
votes
3
answers
3k
views
maxScale or minScale don't work in vector (from WFS) layer
var options =
{
projection: "EPSG:900913",
displayProjection: "EPSG:4326",
units: 'm'
};
map = new OpenLayers.Map('map', options);
ilceSinir = new OpenLayers....
