diff --git a/src/core/src/renderable/hips/mod.rs b/src/core/src/renderable/hips/mod.rs
index 0dc65b82..1e467f0b 100644
--- a/src/core/src/renderable/hips/mod.rs
+++ b/src/core/src/renderable/hips/mod.rs
@@ -36,7 +36,7 @@ use std::collections::HashSet;
 // Recursively compute the number of subdivision needed for a cell
 // to not be too much skewed
 
-use crate::survey::buffer::ImageSurveyTextures;
+use crate::survey::buffer::HiPS2DBuffer;
 use crate::survey::texture::Texture;
 
 use raytracing::RayTracer;
@@ -210,7 +210,7 @@ pub fn get_raytracer_shader<'a>(
 pub struct HiPS {
     //color: Color,
     // The image survey texture buffer
-    textures: ImageSurveyTextures,
+    textures: HiPS2DBuffer,
 
     // The projected vertices data
     // For WebGL2 wasm, the data are interleaved
@@ -328,7 +328,7 @@ impl HiPS {
             .unbind();
 
         let num_idx = 0;
-        let textures = ImageSurveyTextures::new(gl, config)?;
+        let textures = HiPS2DBuffer::new(gl, config)?;
 
         let gl = gl.clone();
         let footprint_moc = None;
@@ -786,11 +786,6 @@ impl HiPS {
         self.textures.config_mut()
     }
 
-    #[inline]
-    pub fn get_ready_time(&self) -> &Option<Time> {
-        &self.textures.start_time
-    }
-
     pub fn draw(
         &self,
         shaders: &mut ShaderManager,
diff --git a/src/core/src/survey/buffer.rs b/src/core/src/survey/buffer.rs
index ff718eaf..4255768f 100644
--- a/src/core/src/survey/buffer.rs
+++ b/src/core/src/survey/buffer.rs
@@ -10,9 +10,7 @@ use al_api::hips::ImageExt;
 use al_core::webgl_ctx::WebGlRenderingCtx;
 
 use al_core::image::format::ImageFormat;
-#[cfg(feature = "webgl2")]
-use al_core::image::format::{R16I, R32I, R8UI};
-use al_core::image::format::{R32F, R64F, RGB8U, RGBA8U};
+use al_core::image::format::{R16I, R32F, R32I, R64F, R8UI, RGB8U, RGBA8U};
 use al_core::image::Image;
 use al_core::shader::{SendUniforms, ShaderBound};
 use al_core::Texture2DArray;
@@ -124,29 +122,21 @@ impl HEALPixCellHeap {
 }
 
 // Fixed sized binary heap
-pub struct ImageSurveyTextures {
+pub struct HiPS2DBuffer {
     // Some information about the HiPS
-    pub config: HiPSConfig,
+    config: HiPSConfig,
     heap: HEALPixCellHeap,
 
     num_root_textures_available: u8,
     size: usize,
 
-    pub textures: HashMap<HEALPixCell, Texture>,
-    pub base_textures: [Texture; NUM_HPX_TILES_DEPTH_ZERO],
-    //pub cutoff_values_tile: Rc<RefCell<HashMap<HEALPixCell, (f32, f32)>>>,
+    textures: HashMap<HEALPixCell, Texture>,
+    base_textures: [Texture; NUM_HPX_TILES_DEPTH_ZERO],
 
     // Array of 2D textures
-    pub texture_2d_array: Texture2DArray,
-
-    // A boolean ensuring the root textures
-    // have already been loaded
-    //ready: bool,
-    pub start_time: Option<Time>,
+    texture_2d_array: Texture2DArray,
 
     available_tiles_during_frame: bool,
-    //num_base_textures: usize,
-    //exec: Rc<RefCell<TaskExecutor>>,
 }
 
 // Define a set of textures compatible with the HEALPix tile format and size
@@ -189,8 +179,8 @@ fn create_texture_array<F: ImageFormat>(
     )
 }
 
-impl ImageSurveyTextures {
-    pub fn new(gl: &WebGlContext, config: HiPSConfig) -> Result<ImageSurveyTextures, JsValue> {
+impl HiPS2DBuffer {
+    pub fn new(gl: &WebGlContext, config: HiPSConfig) -> Result<HiPS2DBuffer, JsValue> {
         let size = 128 - NUM_HPX_TILES_DEPTH_ZERO;
         // Ensures there is at least space for the 12
         // root textures
@@ -231,12 +221,11 @@ impl ImageSurveyTextures {
             ChannelType::R64F => create_texture_array::<R64F>(gl, &config)?,
         };
         // The root textures have not been loaded
-        //let ready = false;
+
         let num_root_textures_available = 0;
         let available_tiles_during_frame = false;
-        let start_time = None;
-        //let num_base_textures = 0;
-        Ok(ImageSurveyTextures {
+
+        Ok(HiPS2DBuffer {
             config,
             heap,
 
@@ -244,12 +233,8 @@ impl ImageSurveyTextures {
             num_root_textures_available,
             textures,
             base_textures,
-            //num_base_textures,
             texture_2d_array,
             available_tiles_during_frame,
-
-            //ready,
-            start_time,
         })
     }
 
@@ -295,7 +280,6 @@ impl ImageSurveyTextures {
         //self.ready = false;
         self.num_root_textures_available = 0;
         self.available_tiles_during_frame = false;
-        self.start_time = None;
 
         Ok(())
     }
@@ -316,18 +300,9 @@ impl ImageSurveyTextures {
             }
         }
 
-        //self.set_ready();
-
         Ok(())
     }
 
-    /*pub fn set_ready(&mut self) {
-        self.ready = true;
-        // The survey is ready
-        self.start_time = Some(Time::now());
-        self.num_root_textures_available = NUM_HPX_TILES_DEPTH_ZERO;
-    }*/
-
     // This method pushes a new downloaded tile into the buffer
     // It must be ensured that the tile is not already contained into the buffer
     pub fn push<I: Image + std::fmt::Debug>(
@@ -355,29 +330,10 @@ impl ImageSurveyTextures {
                     let mut texture = self.textures.remove(&oldest_texture.cell).expect(
                         "Texture (oldest one) has not been found in the buffer of textures",
                     );
-                    // Clear and assign it to tex_cell
-                    /*let idx = if tex_cell_is_root {
-                        self.num_base_textures += 1;
-                        Some(tex_cell.idx() as i32)
-                    } else {
-                        None
-                    };*/
                     texture.replace(&tex_cell, time_request);
 
                     texture
                 } else {
-                    // The heap buffer is not full, let's create a new
-                    // texture with an unique idx
-                    // The idx is computed based on the current size of the buffer
-
-                    /*let idx = if tex_cell_is_root {
-                        self.num_base_textures += 1;
-                        tex_cell.idx() as usize
-                    } else {
-                        //NUM_HPX_TILES_DEPTH_ZERO + (self.heap.len() - self.num_base_textures)
-                        self.heap.len()
-                    };*/
-                    //let idx = NUM_HPX_TILES_DEPTH_ZERO + (self.heap.len() - self.num_base_textures);
                     let idx = NUM_HPX_TILES_DEPTH_ZERO + self.heap.len();
 
                     Texture::new(&tex_cell, idx as i32, time_request)
@@ -411,7 +367,6 @@ impl ImageSurveyTextures {
                 &mut self.base_textures[idx as usize]
             };
 
-            //let missing = image.is_none();
             send_to_gpu(
                 cell,
                 texture,
@@ -423,25 +378,9 @@ impl ImageSurveyTextures {
             texture.append(
                 cell, // The tile cell
                 &self.config,
-                //missing,
             );
 
             self.available_tiles_during_frame = true;
-            //self.ready = true;
-            /*if self.start_time.is_none() {
-                self.start_time = Some(Time::now());
-            }*/
-
-            /*if tex_cell.is_root(self.config.delta_depth()) && texture.is_available() {
-                self.num_root_textures_available += 1;
-                debug_assert!(self.num_root_textures_available <= NUM_HPX_TILES_DEPTH_ZERO);
-
-                if self.num_root_textures_available == NUM_HPX_TILES_DEPTH_ZERO {
-                    self.ready = true;
-                    // The survey is ready
-                    //self.start_time = Some(Time::now());
-                }
-            }*/
         }
 
         Ok(())
@@ -614,33 +553,6 @@ impl ImageSurveyTextures {
         &mut self.config
     }
 
-    /*pub fn is_ready(&self) -> bool {
-        self.ready
-    }*/
-
-    // Get the textures in the buffer
-    // The resulting array is uniq sorted
-    /*fn get_allsky_textures(&self) -> [Option<&Texture>; NUM_HPX_TILES_DEPTH_ZERO] {
-        //debug_assert!(self.is_ready());
-        /*let mut textures = self.textures.values().collect::<Vec<_>>();
-        textures.sort_unstable();
-        textures*/
-        [
-            self.textures.get(&HEALPixCell(0, 0)),
-            self.textures.get(&HEALPixCell(0, 1)),
-            self.textures.get(&HEALPixCell(0, 2)),
-            self.textures.get(&HEALPixCell(0, 3)),
-            self.textures.get(&HEALPixCell(0, 4)),
-            self.textures.get(&HEALPixCell(0, 5)),
-            self.textures.get(&HEALPixCell(0, 6)),
-            self.textures.get(&HEALPixCell(0, 7)),
-            self.textures.get(&HEALPixCell(0, 8)),
-            self.textures.get(&HEALPixCell(0, 9)),
-            self.textures.get(&HEALPixCell(0, 10)),
-            self.textures.get(&HEALPixCell(0, 11)),
-        ]
-    }*/
-
     pub fn get_texture_array(&self) -> &Texture2DArray {
         &self.texture_2d_array
     }
@@ -678,7 +590,7 @@ fn send_to_gpu<I: Image>(
     Ok(())
 }
 
-impl SendUniforms for ImageSurveyTextures {
+impl SendUniforms for HiPS2DBuffer {
     // Send only the allsky textures
     fn attach_uniforms<'a>(&self, shader: &'a ShaderBound<'a>) -> &'a ShaderBound<'a> {
         // Send the textures
@@ -707,7 +619,7 @@ impl SendUniforms for ImageSurveyTextures {
     }
 }
 
-impl Drop for ImageSurveyTextures {
+impl Drop for HiPS2DBuffer {
     fn drop(&mut self) {
         // Cleanup the heap
         self.heap.clear();
diff --git a/src/js/MOC.js b/src/js/MOC.js
index b2263b1c..fda717a3 100644
--- a/src/js/MOC.js
+++ b/src/js/MOC.js
@@ -94,6 +94,10 @@ export let MOC = (function() {
     /**
      *  Return a value between 0 and 1 denoting the fraction of the sky
      *  covered by the MOC
+     * 
+     * @memberof MOC
+     * 
+     * @returns {number} The sky fraction covered by the MOC 
      */
     MOC.prototype.skyFraction = function() {
         return this.skyFrac;
@@ -190,6 +194,11 @@ export let MOC = (function() {
         }
     };
 
+    /**
+     * Show the MOC object 
+     *
+     * @memberof MOC
+     */
     MOC.prototype.show = function() {
         if (this.isShowing) {
             return;
@@ -198,6 +207,11 @@ export let MOC = (function() {
         this.reportChange();
     };
 
+    /**
+     * Hide the MOC object 
+     *
+     * @memberof MOC
+     */
     MOC.prototype.hide = function() {
         if (! this.isShowing) {
             return;
@@ -206,9 +220,15 @@ export let MOC = (function() {
         this.reportChange();
     };
 
-    // Tests whether a given (ra, dec) point on the sky is within the current MOC object
-    //
-    // returns true if point is contained, false otherwise
+    /**
+     * Tests whether a given (ra, dec) point on the sky is within the current MOC object
+     *
+     * @memberof MOC
+     * @param {number} ra - Right-Ascension of the location in degrees and ICRS frame
+     * @param {number} dec - Declination of the location in degrees and ICRS frame
+     *
+     * @returns {boolean} True if the point is contained, false otherwise
+     */
     MOC.prototype.contains = function(ra, dec) {
         if (!this.ready) {
             throw this.name + " is not yet ready, either because it has not been downloaded yet or because it has not been added to the aladin instance."
diff --git a/src/js/Overlay.js b/src/js/Overlay.js
index fc961b7b..eb9fc325 100644
--- a/src/js/Overlay.js
+++ b/src/js/Overlay.js
@@ -75,6 +75,11 @@ export let GraphicOverlay = (function() {
 
 
     // TODO : show/hide methods should be integrated in a parent class
+    /**
+     * Show the graphic overlay
+     *
+     * @memberof GraphicOverlay
+     */
     GraphicOverlay.prototype.show = function() {
         if (this.isShowing) {
             return;
@@ -86,6 +91,11 @@ export let GraphicOverlay = (function() {
         this.reportChange();
     };
 
+     /**
+     * Hide the graphic overlay
+     *
+     * @memberof GraphicOverlay
+     */
     GraphicOverlay.prototype.hide = function() {
         if (! this.isShowing) {
             return;
@@ -97,6 +107,11 @@ export let GraphicOverlay = (function() {
         this.reportChange();
     };
 
+     /**
+     * Toggle on/off the graphic overlay
+     *
+     * @memberof GraphicOverlay
+     */
     GraphicOverlay.prototype.toggle = function() {
         if (! this.isShowing) {
             this.show()
@@ -106,6 +121,13 @@ export let GraphicOverlay = (function() {
     };
 
     // return an array of Footprint from a STC-S string
+    /**
+     * Parse a STCS string and returns a list of footprints (only circles, polygons and ellipses given in ICRS frame are handled).
+     *
+     * @memberof GraphicOverlay
+     * 
+     * @returns {Circle[]|Polyline[]|Ellipse[]} The list of mixed circles, polygons and ellipses
+     */
     GraphicOverlay.parseSTCS = function(stcs, options) {
         options = options || {};
 
@@ -188,7 +210,13 @@ export let GraphicOverlay = (function() {
         return footprints;
     };
 
-    // ajout d'un tableau d'overlays (= objets Footprint, Circle ou Polyline)
+     /**
+     * Add an array (or single) shapes (i.e. Footprint, Circle, Polyline, Ellipse, Vector, ...)
+     *
+     * @memberof GraphicOverlay
+     * 
+     * @param {Footprint[]|Circle[]|Polyline[]|Ellipse[]|Vector[]} overlaysToAdd - a list (or single) shapes to add to the overlay 
+     */
     GraphicOverlay.prototype.addFootprints = function(overlaysToAdd) {
         overlaysToAdd = [].concat(overlaysToAdd)
 
@@ -215,7 +243,15 @@ export let GraphicOverlay = (function() {
     };
 
 
-    // return a footprint by index
+    /**
+     * Returns a shape by an index
+     *
+     * @memberof GraphicOverlay
+     * 
+     * @param {number} idx - The index of the shape to retrieve
+     * 
+     * @returns {Footprint|Circle|Polyline|Ellipse|Vector} The shape
+     */
     GraphicOverlay.prototype.getFootprint = function(idx) {
         if (idx<this.footprints.length) {
             return this.footprints[idx];
@@ -232,6 +268,11 @@ export let GraphicOverlay = (function() {
         this.view.insertOverlay(this, idx);
     };
 
+    /**
+     * Clear the overlay of all its shapes
+     *
+     * @memberof GraphicOverlay
+     */
     GraphicOverlay.prototype.removeAll = function() {
         // TODO : RAZ de l'index
         //this.overlays = [];
@@ -279,6 +320,16 @@ export let GraphicOverlay = (function() {
         ctx.restore();
     };
 
+    /**
+     * Increase the brightness of a color by a percentage
+     *
+     * @memberof GraphicOverlay
+     * 
+     * @param {string} hex - The color given in hexadecimal e.g. '#ffa0bb'
+     * @param {number} percent - The percentage to increase the brightness of
+     * 
+     * @returns {string} The new color given as an hexadecimal string
+     */
     GraphicOverlay.increaseBrightness = function(hex, percent){
         // strip the leading # if it's there
         hex = hex.replace(/^\s*#|\s*$/g, '');
@@ -298,16 +349,37 @@ export let GraphicOverlay = (function() {
                 ((0|(1<<8) + b + (256 - b) * percent / 100).toString(16)).substr(1);
     };
 
+    /**
+     * Set the color of the shapes inside the overlay
+     *
+     * @memberof GraphicOverlay
+     * 
+     * @param {string} color - the new color in hexadecimal e.g. '#ff00ff'
+     */
     GraphicOverlay.prototype.setColor = function(color) {
         this.color = color;
         this.reportChange();
     };
 
+    /**
+     * Set the line width of the shapes inside the overlay
+     *
+     * @memberof GraphicOverlay
+     * 
+     * @param {number} lineWidth - the new line width in pixels
+     */
     GraphicOverlay.prototype.setLineWidth = function(lineWidth) {
         this.lineWidth = lineWidth;
         this.reportChange();
     };
 
+    /**
+     * Set the dash line property
+     *
+     * @memberof GraphicOverlay
+     * 
+     * @param {Array.<number>} [lineDash=[]] - See the segments property {@link https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/setLineDash#segments| here}
+     */
     GraphicOverlay.prototype.setLineDash = function(lineDash) {
         this.lineDash = lineDash;
         this.reportChange();